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Displaying record number 2124

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MAb ID	PG9
HXB2 Location	gp160	gp160 Epitope Map
Author Location	gp120(126-196)
Epitope	(Discontinuous epitope)
Subtype	A
Ab Type	gp120 V2 // V2 glycan(V2g) // V2 apex, quaternary structure
Neutralizing	P (tier 2) View neutralization details
Contacts and Features	View contacts and features
Species (Isotype)	human(IgG1)
Patient	Donor 24
Immunogen	HIV-1 infection
Keywords	acute/early infection, ADCC, antibody binding site, antibody gene transfer, antibody generation, antibody interactions, antibody lineage, antibody polyreactivity, antibody sequence, assay or method development, autoantibody or autoimmunity, binding affinity, broad neutralizer, chimeric antibody, computational epitope prediction, elite controllers, escape, genital and mucosal immunity, germline, glycosylation, immunoprophylaxis, immunotherapy, junction or fusion peptide, memory cells, mother-to-infant transmission, neutralization, polyclonal antibodies, rate of progression, review, structure, subtype comparisons, vaccine antigen design, vaccine-induced immune responses, variant cross-reactivity

Notes

Showing 174 of 174 notes.

PG9: Analyses of all PDB HIV1-Env trimer (prefusion, closed) structures fulfilling certain parameters of resolution were performed to classify them on the basis of (a) antibody class which was informed by parental B cells as well as structural recognition, and (b) Env residues defining recognized HIV epitopes. Structural features of the 206 HIV epitope and bNAb paratopes were correlated with functional properties of the breadth and potency of neutralization against a 208-strain panel. bNAbs with >25% breadth of neutralization belonged to 20 classes of antibody with a large number of protruding loops and somatic hypermutation (SHM). HIV epitopes recognized placed the bNAbs into 6 categories (viz. V1V2, Glycan-V3, CD4-binding site, Silent face center, Fusion peptide and Subunit Interface). The epitopes contained high numbers of independent sequence segments and glycosylated surface area. PG9-Env formed a distinct group within the V1V2 category, Class PG9 and it has extensive D-gene contribution. Crystal structure data on B-cell culture identified PG9 Fab complexed to V1V2 region of strain ZM109 was found in PDB ID: 3U2S. Chuang2019 (antibody binding site, antibody interactions, neutralization, binding affinity, antibody sequence, structure, antibody lineage, broad neutralizer)
PG9: In an effort to identify new Env immunogens able to elicit bNAbs, this study looked at Envs derived from rare individuals who possess bNAbs and are elite viral suppressors, hypothesizing that in at least some people the antibodies may mediate durable virus control. The Env proteins recovered from these individuals may more closely resemble the Envs that gave rise to bNAbs compared to the highly diverse viruses isolated from normal progressors. This study identified a treatment-naive elite suppressor, EN3, whose serum had broad neutralization. The Env sequences of EN3 had much fewer polymorphisms, compared to those of a normal progressor, EN1, who also had broad serum neutralization. This result confirmed other reports of slower virus evolution in elite suppressors. EN3 Envelope proteins were unusual in that most possessed two extra cysteines within an elongated V1 region. The impact of the extra cysteines on the binding to bNAbs, virus infectivity, and sensitivity to neutralization suggested that structural motifs in V1 can affect infectivity, and that rare viruses may be prevented from developing escape. As part of this study, the neutralization of pseudotype viruses for EN3 Env clones was assayed for several bnAbs (PG9, PG16, PGT145, PGT121, PGT128, VRC01, 4E10, and 35O22). Hutchinson2019 (elite controllers, neutralization, vaccine antigen design, polyclonal antibodies)
PG9: The Chinese HIV Reference Laboratory produced 124 pseudoviruses from patients with subype B, BC, and CRF01 infections. These viruses were assigned to tiers based on their neutralization by a panel of patient sera. Their neutralization sensitivities were also measured against a panel of well-characterized mAbs (2F5, b12, 2G12, 4E10, 10E8, VRC01, VRC-CH31, CH01, PG9, PG16, PGT121, PGT126). Nie2020 (assay or method development, neutralization)
PG9: Extensive structural and biochemical analyses demonstrated that PGT145 achieves recognition and neutralization by targeting quaternary structure of the cationic trimer apex with long and unusually stabilized anionic β-hairpin HCDR3 loops. Compared to PGT145, PG9 showed increased breadth, neutralization potency, and maximum percentage neutralization (MPN) in the presence of complex/hybrid glycans. In BG505.Env.C2 alanine-scanning neutralization assays, PG9 had similar results as CH01, consistent with both CH01 and PG9 being representatives of hammerhead-class, and very dissimilar results to PGT145-like antibodies. Lee2017 (antibody binding site, neutralization)
PG9: Three vaccine regimens administered in guinea pigs over 200 weeks were compared for ability to elicit NAb polyclonal sera. While tier 1 NAb responses did increase with vaccination, tier 2 NAb heterologous responses did not. The 3 regimens were C97 (monovalent, Clade C gp140), 4C (tetravalent, 4 Clade C mosaic gp140s), ABCM (tetravalent, Clades A, B, C and mosaic gp140s). Polyclonal sera generated from the 4C and ABCM regimens, compared to the C97 regimen, were able to more successfully outcompete PG9 binding to gp140 antigens. Bricault2018 (antibody generation, vaccine-induced immune responses, polyclonal antibodies)
PG9: Novel Env pseudoviruses were derived from 22 patients in China infected with subtype CRF01_AE viruses. Neutralization IC50 was determined for 11 bNAbs: VRC01, NIH45-46G54W, 3BNC117, PG9, PG16, 2G12, PGT121, 10-1074, 2F5, 4E10, and 10E8. The CRF01_AE pseudoviruses exhibited different susceptibility to these bNAbs. Overall, 4E10, 10E8, and 3BNC117 neutralized all 22 env-pseudotyped viruses, followed by NIH45-46G54W and VRC01, which neutralized more than 90% of the viruses. 2F5, PG9, and PG16 showed only moderate breadth, while the other three bNAbs neutralized none of these pseudoviruses. Specifically, 10E8, NIH45-46G54Wand 3BNC117 showed the highest efficiency, combining neutralization potency and breadth. Mutations at position 160, 169, 171 were associated with resistance to PG9 and PG16, while loss of a potential glycan at position 332 conferred insensitivity to V3-glycan-targeting bNAbs. These results may help in choosing bNAbs that can be used preferentially for prophylactic or therapeutic approaches in China. Wang2018a (assay or method development, neutralization, subtype comparisons)
PG9: The authors mutated two conserved tyrosine (Y) residues within the V2 loop of gp120 Y177 and Y173, individually or in combination, by replacing them with either phenylalanine (F) or alanine (A) in a clade B, tier 1B HIV-1 Env protein (BaL), and in a number of tier 2 HIV-1 Envs from different clades, namely, BG505 (clade A), JR-FL and JR-CSF (clade B), and CM244 (clade E). A consistent hierarchy of neutralization sensitivity was seen among the mutants, with a greater impact of Y177 over Y173 single mutations, of double over single mutations, and of A over F substitutions. The double-alanine mutation in mutant HIV-1 BaL, Y173A Y177A, increased sensitivity to all the weakly neutralizing MAbs tested and even rendered the virus sensitive to non-neutralizing antibodies against the CD4 binding site, such as F105, 654-30D, and b13. When tested against bNAbs instead, there was a trend to decrease neutralization sensitivity compared to WT, with the exception of N6, PGT151, 10E8, and 2G12, for which there was no change, and of 2F5 and 4E10, which were more effective against the mutant compared to the WT. Guzzo2018 (antibody binding site, binding affinity)
PG9: To reduce local V2 flexibility and improve the binding of V2-dependent bNAbs and germline precursor bNAbs, the authors designed BG505 SOSIP.664 trimer variants whose V1 and V2 domains were stabilized by introducing disulfide bonds either within the V2 loop or between the V1 and V2 loops. The resulting SOSIP trimer variants — E153C/K178C, E153C/K178C/G152E and I184C/E190C — have improved reactivity with V2 bNAbs and their inferred germline precursors and are more sensitive to neutralization by V2 bNAbs. PGT121, PG9, PG16, and CH01 bound better to the E153C/R178C/G152E mutant than to SOSIP.664. The I184C/E190C mutant bound all the V2 bNAbs (PG9, PG16, PGT145, VRC26.09, and CH01) better than SOSIP.664. I184C/E190C was more sensitive to neutralization by V2 bNAbs compared with BG505 (by 5-fold for PG9, 3-fold for PG16, 6-fold for CH01, and 3-fold for PGDM1400). deTaeye2019 (antibody interactions, variant cross-reactivity, binding affinity, structure, broad neutralizer)
PG9: The authors used genome-editing techniques (CRISPR-Cas9) to modify HIV specific B cell receptors. In particular, they replaced the heavy chain variable region in B cell lines with that from the HIV broadly neutralizing antibody PG9. The chimeric PG9 antibodies they created could neutralized one or more of the PG9-sensitive viruses, and most neutralized multiple viruses from different clades in a global panel, although none of the chimeric antibodies were as broadly neutralizing as the original PG9 HC/LC pair. Voss2019 (neutralization, antibody sequence, broad neutralizer, chimeric antibody)
PG9: This study looks at the role of somatic mutations within antibody variable and framework regions (FWR) in bNAbs and how these mutations alter thermostability and neutralization as the Ab lineage reaches maturation. The emergence and selection of different mutations in the complementarity-determining and framework regions are necessary to maintain a balance between antibody function and stability. The study shows that all major classes of bnAbs (DH2070, CH103, CH235 etc.) have lower thermostability than their corresponding inferred UCA antibodies. Henderson2019 (neutralization, antibody lineage, broad neutralizer)
PG9: Two HIV-1-infected individuals, VC10014 and VC20013, were monitored from early infection until well after they had developed broadly neutralizing activity. The bNAb activity developed about 1 year after infection and mapped to a single epitope in both subjects. Isolates from each subject, taken at five different time points, were tested against monoclonal bNAbs: VRC01, B12, 2G12, PG9, PG16, 4E10, and 2F5. In subject VC10014, the bNAb activity developed around 1 year postinfection and targeted an epitope that overlaps the CD4-BS and is similar to (but distinct from) bNAb HJ16. In the case of VC20013, the bNAb activity targeted a novel epitope in the MPER that is critically dependent on residue 677 (mutation K677N). Sather2014 (neutralization, broad neutralizer)
PG9: This study demonstrated that bNAb signatures can be utilized to engineer HIV-1 Env vaccine immunogens eliciting Ab responses with greater neutralization breadth. Data from four large virus panels were used to comprehensively map viral signatures associated with bNAb sensitivity, hypervariable region characteristics, and clade effects. The bNAb signatures defined for the V2 epitope region were then employed to inform immunogen design in a proof-of-concept exploration of signature-based epitope targeted (SET) vaccines. V2 bNAb signature-guided mutations were introduced into Env 459C to create a trivalent vaccine which resulted in increased breadth of NAb responses compared with Env 459C alone. PG9 was used as V2 Ab and Clade B was resistant to PG9. Based on structural contacts for PG9, phylogenetically corrected signatures and statistical support for other V2 Abs contacts were analyzed. Bricault2019 (antibody binding site, vaccine antigen design, computational epitope prediction, broad neutralizer)
PG9: The influence of a V2 State 2/3-stabilizing Env mutation, L193A, on ADCC responses mediated by sera from HIV-1-infected individuals was evaluated. Conformations spontaneously sampled by the Env trimer at the surface of infected cells had a significant impact on ADCC. State 1-preferring ligand PG9 recognized L193A variants of CH58 and CH77 IMCs with less efficiently compared to the WT. Prevost2018 (ADCC)
PG9: A simple method to quantify and compare serum neutralization probabilities in described. The method uses logistic regression to model the probability that a serum neutralizes a virus with an ID50 titer above a cutoff. The neutralization potency (NP) identifies where the probabilities of neutralizing and not neutralizing a virus are equal and is not absolute as it depends on the ID50 cutoff. It provides a continuous measure for sera, which builds upon established tier categories now used to rate virus sensitivity. These potency comparisons are similar to comparing geometric mean neutralization titers, but instead are represented in tier-like terms. Increasing the number of bNAbs increases NP and slope, where the higher the slope, the sharper the boundary (lower scatter) between viruses neutralized and not neutralized. PG9 was used in analysis of monoclonal bNAb combinations. Hraber2018 (assay or method development, neutralization)
PG9: This review summarizes current advances in antibody lineage-based design and epitope-based vaccine design. Antibody lineage-based design is described for VRC01, PGT121 and PG9 antibody classes, and epitope-based vaccine design is described for the CD4-binding site, as well as fusion peptide and glycan-V3 cites of vulnerability. Kwong2018 (antibody binding site, vaccine antigen design, vaccine-induced immune responses, review, antibody lineage, broad neutralizer, junction or fusion peptide)
PG9: This review discusses the identification of super-Abs, where and how such Abs may be best applied and future directions for the field. PG9, a prototype super-Ab, was isolated from direct functional screening of B cell clones from an HIV elite neutralizer and was an order of magnitude more potent than first-generation bNAbs. Recently recombinant native-like HIV Env trimers have enabled the identification of exceptionally potent ‘PG9-class’ bNAbs e.g., PG16, PGT141-144, CH01-04, PGDM1400–1412 and CAP256-VRC26.01-12. Antigenic region V2 apex (Table:1) Walker2018 (antibody binding site, review, broad neutralizer)
PG9: The authors selected an optimal panel of diverse HIV-1 envelope glycoproteins to represent the antigenic diversity of HIV globally in order to be used as antigen candidates. The selection was based on genetic and geographic diversity, and experimentally and computationally evaluated humoral responses. The eligibility of the envelopes as vaccine candidates was evaluated against a panel of antibodies for breadth, affinity, binding and durability of vaccine-elicited responses. The antigen panel was capable of detecting the spectrum of V2-specific antibodies that target epitopes from the V2 strand C (V2p), the integrin binding motif in V2 (V2i), and the quaternary epitope at the apex of the trimer (V2q). Yates2018 (vaccine antigen design, vaccine-induced immune responses, binding affinity)
PG9: The effects of 16 glycoengineering (GE) methods on the sensitivities of 293T cell-produced pseudoviruses (PVs) to a large panel of bNAbs were investigated. Some bNAbs were dramatically impacted. PG9 and were up to 30-fold more potent against PVs produced with co-transfected α-2,6 sialyltransferase. PGT151 and PGT121 were more potent against PVs with terminal SA removed. 35O22 and CH01 were more potent against PV produced in GNT1-cells. The effects of GE on bNAbs VRC38.01, VRC13 and PGT145 were inconsistent between Env strains, suggesting context-specific glycan clashes. Overexpressing β-galactosyltransferase during PV production 'thinned' glycan coverage, by replacing complex glycans with hybrid glycans. This impacted PV sensitivity to some bNAbs. Maximum percent neutralization by excess bnAb was also improved by GE. Remarkably, some otherwise resistant PVs were rendered sensitive by GE. Germline-reverted versions of some bnAbs usually differed from their mature counterparts, showing glycan indifference or avoidance, suggesting that glycan binding is not germline-encoded but rather, it is gained during affinity maturation. Overall, these GE tools provided new ways to improve bnAb-trimer recognition that may be useful for informing the design of vaccine immunogens to try to elicit similar bnAbs. Crooks2018 (vaccine antigen design, antibody lineage)
PG9: A panel of bnAbs were studied to assess ongoing adaptation of the HIV-1 species to the humoral immunity of the human population. Resistance to neutralization is increasing over time, but concerns only the external glycoprotein gp120, not the MPER, suggesting a high selective pressure on gp120. Almost all the identified major neutralization epitopes of gp120 are affected by this antigenic drift, suggesting that gp120 as a whole has progressively evolved in less than 3 decades. Bouvin-Pley2014 (neutralization)
PG9: A rare glycan hole at the V2 apex is enriched in HIV isolates neutralized by inferred precursors of prototype V2-apex bNAbs. To investigate whether this feature could focus neutralizing responses onto the apex bnAb region, rabbits were immunized with soluble trimers adapted from these Envs. Potent autologous tier 2 neutralizing responses targeting basic residues in strand C of the V2 region, which forms the core epitope for V2-apex bnAbs, were observed. Neutralizing monoclonal antibodies (mAbs) derived from these animals display features promising for subsequent broadening of the response. Four human anti-V2 bnAbs (PG9, CH01, PGT145, and CAP256.09) were used as a basis of comparison. Voss2017 (vaccine antigen design)
PG9: This study describes the generation of CHO cell lines stably expressing the following vaccine Env Ags: CRF01_AE A244 Env gp120 protein (A244.AE) and 6240 Env gp120 protein (6240.B). The antigenic profiles of the molecules were assessed with a panel of well-characterized mAbs recognizing critical epitopes and glycosylation analysis confirming previously identified sites and revealing unknown sites at non-consensus motifs. A244.AE gp120 showed low level of binding to PG9 in ELISA EC50 and Surface Plasmon Resonance (SPR) assays. 6240.B gp120 exhibited binding to PG9. Wen2018 (glycosylation, vaccine antigen design)
PG9: The prophylactic and therapeutic potential of an engineered single gene–encoded tandem bispecific immunoadhesin (IA) molecule BiIA-SG was studied. Before engineering BiIAs, codon-optimized scFvs of bNAbs PG9, PG16, PGT128, VRC01, and Hu5A8 were synthesized. The VL/VH domain of each scFv was engineered as a corresponding IA by fusion with human IgG1-Fc to generate IA-PG9, IA-PG16, IA-PGT128, IA-VRC01, and IA-Hu5A8. While all IAs exhibited specific anti–HIV-1 activity, only IA-PGT128 displayed similar potency and the same sigmoidal slope of 100% neutralization as previously described for the native PGT128, and IA-PGT128 in combination with IA-Hu5A8 exhibited the best synergistic effect based on computational synergy volumes. IA-PGT128 and IA-Hu5A8 were therefore used for BiIA construction. Wu2018
PG9: Assays of poly- and autoreactivity demonstrated that broadly neutralizing NAbs are significantly more poly- and autoreactive than non-neutralizing NAbs. PG9 is polyreactive, but not autoreactive. Liu2015a (autoantibody or autoimmunity, antibody polyreactivity)
PG9: Panels of C clade pseudoviruses were computationally downselected from the panel of 200 C clade viruses defined by Rademeyer et al. 2016. A 12-virus panel was defined for the purpose of screening sera from vaccinees. Panels of 50 and 100 viruses were defined as smaller sets for use in testing magnitude and breadth against C clade. Published neutralization data for 16 mAbs was taken from CATNAP for the computational selections: 10-1074, 10-1074V, PGT121, PGT128, VRC26.25, VRC26.08, PGDM1400, PG9, PGT145, VRC07-523, 10E8, VRC13, 3BNC117, VRC07, VRC01, 4E10. Hraber2017 (assay or method development, neutralization)
PG9: A panel of 14 pseudoviruses of subtype CRF01_AE was developed to assess the neutralization of several neutralizing antibodies (b12, PG9, PG16, 4E10, 10E8, 2F5, PGT121, PGT126, 2G12). Neutralization was assessed in both TZM-bl and A3R5 cell-based assays. Most viruses were more susceptible to mAb-neutralization in A3R5 than in the TZM-bl cell-based assay. The increased neutralization sensitivity observed in the A3R5 assay was not linked to the year of virus transmission or to the stages of infection, but chronic viruses from the years 1990-92 were more sensitive to neutralization than the more current viruses, in both assays. Chenine2018 (assay or method development, neutralization, subtype comparisons)
PG9: The immunologic effects of mutations in the Env cytoplasmic tail (CT) that included increased surface expression were explored using a vaccinia prime/protein boost protocol in mice. After vaccinia primes, CT- modified Envs induced up to 7-fold higher gp120-specific IgG, and after gp120 protein boosts, they elicited up to 16-fold greater Tier-1 HIV-1 neutralizing antibody titers. Hogan2018 (vaccine antigen design)
PG9: Env trimers were engineered with selective deglycosylation around the CD4 binding site to see if they could be useful vaccine antigens. The neutralization of glycan-deleted trimers was tested for a set of bnAbs (PG9, PGT122, PGT135, b12, CH103, HJ16, VRC01, VRC13, PGT151, 8ANC195, 35O22), and the antigens elicited potent neutralization based on the CD4 supersite. A crystal structure was made of one of these Env trimers bound to Fabs 35O22 and 3H+109L. Guinea pigs vaccinated with these antigens achieved neutralization of deglycosylated Envs. Glycan-deleted Env trimers may be useful as priming antigens to increase the frequency of CD4 site-directed antibodies. Zhou2017 (glycosylation, neutralization, vaccine antigen design, vaccine-induced immune responses)
PG9: Env from of a highly neutralization-resistant isolate, CH120.6, was shown to be very stable and conformationally-homogeneous. Its gp140 trimer retains many antigenic properties of the intact Env, while its monomeric gp120 exposes more epitopes. Thus trimer organization and stability are important determinants for occluding epitopes and conferring resistance to antibodies. Among a panel of 21 mAbs, CH120.6 was resistant to neutralization by all non-neutralizing and strain-specific mAbs, regardless of the location of their epitopes. It was weakly neutralized by several broadly-neutralizing mAbs (VRC01, NIH45-46, 12A12, PG9, PG16, PGT128, 4E10, and 10E8), and well neutralized by only 2 (PGT145 and 10-1074). Cai2017 (neutralization)
PG9: A panel of mAbs (2G12, VRC01, HJ16, 2F5, 4E10, 35O22, PG9, PGT121, PGT126, 10-1074) was tested to compare their efficacy in cell-free versus cell-cell transmission. Almost all bNAbs (with the exception of anti-CD4 mAb Leu3a) blocked cell-free infection with greater potency than cell-cell infection, and showed greater potency in neutralization of cell-free viruses. The lower effectiveness on neutralization was particularly pronounced for transmitted/founder viruses, and less pronounced for chronic and lab-adapted viruses. The study highlights that the ability of an antibody to inhibit cell-cell transmission may be an important consideration in the development of Abs for prophylaxis. Li2017 (immunoprophylaxis, neutralization)
PG9: The next generation of a computational neutralization fingerprinting (NFP) being used as a way to predict polyclonal Ab responses to HIV infection is presented. A new panel of 20 pseudoviruses, termed f61, was developed to aid in the assessment of experimental neutralization. This panel was used to assess 22 well-characterized bNAbs and mixtures thereof (HJ16, VRC01, 8ANC195, IGg1b12, PGT121, PGT128, PGT135, PG9, PGT151, 35O22, 10E8, 2F5, 4E10, VRC27, VRC-CH31, VRC-PG20, PG04, VRC23, 12A12, 3BNC117, PGT145, CH01). The new algorithms accurately predicted VRC01-like and PG9-like antibody specificities. Doria-Rose2017 (neutralization, computational epitope prediction)
PG9: This review focuses on the potential role of HIV-1-specific NAbs in preventing HIV-1 infection. Several NAbs have provided protection from infection in SHIV challenge studies in primates: b12, VRC01, VRC07-523LS, 3BNC117, PG9, PGT121, PGT126, 10-1074, 2G12, 4E10, 2F5, 10E8. Pegu2017 (immunoprophylaxis, review)
PG9: The ability of neutralizing and nonneutralizing mAbs to block infection in models of mucosal transmission was tested. Neutralization potency did not fully predict activity in mucosal tissue. CD4bs-specific bNAbs, in particular VRC01, blocked HIV-1 infection across all cellular and tissue models. MPER (2F5) and outer domain glycan (2G12) bNAbs were also efficient in preventing infection of mucosal tissues, while bNAbs targeting V1-V2 glycans (PG9 and PG16) were more variable. Non-nAbs alone and in combinations, were poorly protective against mucosal infection. The protection provided by specific bNAbs demonstrates their potential over that of nonneutralizing antibodies for preventing mucosal entry. PG9 and PG16 were selected to represent mAbs of the V1-V2 glycan class. Cheeseman2017 (genital and mucosal immunity, immunoprophylaxis)
PG9: To understand HIV neutralization mediated by the MPER, antibodies and viruses were studied from CAP206, a patient known to produce MPER-targeted neutralizing mAbs. 41 human mAbs were isolated from CAP206 at various timepoints after infection, and 4 macaque mAbs were isolated from animals immunized with CAP206 Env proteins. Two rare, naturally-occuring single-residue changes in Env were identified in transmitted/founder viruses (W680G in CAP206 T/F and Y681D in CH505 T/F) that made the viruses less resistant to neutralization. The results point to the role of the MPER in mediating the closed trimer state, and hence the neutralization resistance of HIV. CH58 was one of several mAbs tested for neutralization of transmitted founder viruses isolated from clade C infected individuals CAP206 and CH505, compared to T/F viruses containing MPER mutations that confer enhanced neutralization sensitivity. Bradley2016a (neutralization)
PG9: This study performed cyclical permutation of the V1 loop of JRFL in order to develop better gp120 trimers to elicit neutralizing antibodies. Some mutated trimers showed improved binding to several mAbs, including VRC01, VRC03, VRC-PG04, PGT128, PGT145, PGDM1400, b6, and F105. Guinea pigs immunized with prospective trimers showed improved neutralization of a panel of HIV-1 pseudoviruses. Binding of PG9 to JRFL was abolished by mutations N156K or N160K. Kesavardhana2017 (vaccine antigen design, vaccine-induced immune responses)
PG9: This study investigated the ability of native, membrane-expressed JR-FL Env trimers to elicit NAbs. Rabbits were immunized with virus-like particles (VLPs) expressing trimers (trimer VLP sera) and DNA expressing native Env trimer, followed by a protein boost (DNA trimer sera). N197 glycan- and residue 230- removal conferred sensitivity to Trimer VLP sera and DNA trimer sera respectively, showing for the first time that strain-specific holes in the "glycan fence" can allow the development of tier 2 NAbs to native spikes. All 3 sera neutralized via quaternary epitopes and exploited natural gaps in the glycan defenses of the second conserved region of JR-FL gp120. A bioinformatics analysis suggested shared features of one of the trimer VLP sera and monoclonal antibody PG9, consistent with its trimer-dependency. PG9 was 1 of 2 reference PG9-like bNAbs - PG9 and PGT145. Crooks2015 (glycosylation, neutralization)
PG9: Env residue N197 on the BG505-SOSIP trimer was mutated to test the effect of its glycosylation on the binding kinetics of CD4BS and other mAbs. Removal of the glycan had little effect on the overall structure of the molecule. Its removal resulted in increased binding of CD4 and CD4BS antibodies (VRC01, VRC03, V3-3074), but little effect on bNAbs targeting other epitopes (PG9, PG16, PGT145, 17b, A32, 2G12, PGT121, PGT126). Two CD4BS-binding antibodies tested (b12, F105) had insufficient breadth to bind the BG505-SOSIP trimer. Removal of the N197 glycan may allow for the development of better SOSIP immunogens, particularly to elicit CD4BS-specific Abs. Liang2016 (glycosylation, vaccine antigen design)
PG9: Binding of PG9 to properly folded and glycosylated fragments of Env V1/V2 (scaffolds) is described. Scaffolds from 3 different clades of HIV-1 bound to PG9 with high affinity. Mutations I169K, E172V, T161M, N156I, S164G, D167G (includng those outside of the antibody contact region) improved binding. Morales2016 (antibody binding site, vaccine antigen design)
PG9: Chimeric antigen receptors (CAR), i.e., fusion proteins made from single-chain antibodies, may be a useful approach to immunotherapy. A set of mAbs were chosen based on their binding to a variety of sites on Env and availability of antibody sequences. The chimeric receptors were created by fusing the antibody's heavy chain, light chain, and two signaling domains into a single molecule. All 7 antibodies used to make the chimeric receptors (10E8, 3BNC117, PGT126, VRC01, X5, PGT128, PG9) showed specific killing of HIV-1 infected cells and suppression of viral replication against a panel of HIV-1 strains. Ali2016 (immunotherapy, chimeric antibody)
PG9: This review classified and mapped the binding regions of 32 bNAbs isolated 2010-2016. Wu2016 (review)
PG9: This study produced Env SOSIP trimers for clades A (strain BG505), B (strain JR-FL), and G (strain X1193). Based on simulations, the MAb-trimer structures of all MAbs tested needed to accommodate at least one glycan, including both antibodies known to require specific glycans (PG9, PGT121, PGT135, 8ANC195, 35O22) and those that bind the CD4-binding site (b12, CH103, HJ16, VRC01, VRC13). A subset of monoclonal antibodies bound to glycan arrays assayed on glass slides (VRC26.09, PGT121, 2G12, PGT128, VRC13, PGT151, 35O22), while most of the antibodies did not have affinity for oligosaccharide in the context of a glycan array (PG9, PGT145, PGDM1400, PGT135, b12, CH103, HJ16, VRC16, VRC01, VRC-PG04, VRC-CH31, VRC-PG20, 3BNC60, 12A12, VRC18b, VRC23, VRC27, 1B2530, 8ANC131, 8ANC134, 8ANC195). Stewart-Jones2016 (antibody binding site, glycosylation, structure)
PG9: This study assessed the ADCC activity of antibodies of varied binding types, including CD4bs (b6, b12, VRC01, PGV04, 3BNC117), V2 (PG9, PG16), V3 (PGT126, PGT121, 10-1074), oligomannose (2G12), MPER (2F5, 4E10, 10E8), CD4i (17b, X5), C1/C5 (A32, C11), cluster I (240D, F240), and cluster II (98-6, 126-7). ADCC activity was correlated with binding to Env on the surfaces of virus-infected cells. ADCC was correlated with neutralization, but not always for lab-adapted viruses such as HIV-1 NLA-3. vonBredow2016 (ADCC)
PG9: This review summarizes representative anti-HIV MAbs of the first generation (2G12, b12, 2F5, 4E10) and second generation (PG9, PG16, PGT145, VRC26.09, PGDM1400, PGT121, PGT124, PGT128, PGT135, 10-1074, VRC01, 3BNC117, CH103, PGT151, 35O22, 8ANC195, 10E8). Structures, epitopes, VDJ usage, CDR usage, and degree of somatic hypermutation are compared among these antibodies. The use of SOSIP trimers as immunogens to elicit B-cell responses is discussed. Burton2016 (review, structure)
PG9: HIV-1 bNAb eptiope networks were predicted using 4 algorithms informed by neutralization assays using 282 Env from multiclade viruses. Patch clusters of possible Ab epitope regions were tested for significant sensitivity by site-directed mutagenesis. Epitope (Ab binding site) networks of critical Env residues for 21 bNAb (b12, PG9, PG16, PGT121, PGT122, PGT123, PGT125, PGT126, PGT127, PGT128, PGT130, PGT131, PGT135, PGT136, PGT137, PGT141, PGT142, PGT143, PGT144, PGT145 and PGV04) were delineated and found to be located mostly in variable loops of gp120, particularly in V1/V2. Evans2014 (antibody binding site, computational epitope prediction)
PG9: Two stable homogenous gp140 Env trimer spikes, Clade A 92UG037.8 Env and Clade C C97ZA012 Env, were identified. 293T cells stably transfected with either presented fully functional surface timers, 50% of which were uncleaved. A panel of neutralizing and non-neutralizing Abs were tested for binding to the trimers. V1/V2 glycan bNAb PG9 bound cell surface tightly whether the trimer contained its C-terminal or not, and was competed out by sCD4. It was able to neutralize the 92UG037.8 HIV-1 isolate. Chen2015 (neutralization, binding affinity)
PG9: Factors that independently affect bNAb induction and evolution were identified as viral load, length of untreated infection and viral diversity. Ethnically, black subjects induced bNAbs more than white subjects, but this did not correlate with type of Ab response. Fingerprint analyses of induced bNAbs showed strong subtype-dependency, with subtype B inducing significantly higher levels of CD4bs Abs and non-subtype B inducing V2-glycan specific Abs. Of the 239 bNAb antibody inducers found from 4,484 HIV-1 infected subjects,the top 105 inducers' neutralization fingerprint and epitope specificity was determined by comparison to the following antibodies - PG9, PG16, PGDM1400, PGT145 (V2 glycan); PGT121, PGT128, PGT130 (V3 glycan); VRC01, PGV04 (CD4bs) and PGT151 (interface) and 2F5, 4E10, 10E8 (MPER). Rusert2016 (neutralization, broad neutralizer)
PG9: PGT145 was used to positively isolate a subtype B Env trimer immunogen, B41 SOSIP.664-D7324, that exists in two conformations, closed and partially open. bNAbs tested against the trimer were able to neutralize the B41 pseudovirus with a wide range of potencies. All tested non-NAbs did not neutralize B41 (IC₅₀ >50µg/ml). V1/V2 glycan bNAb, PG9, neutralized B41 psuedovirus and bound B41 trimer well. Pugach2015
PG9: The first generation of HIV trimer soluble immunogens, BG505 SOSIP.664 were tested in a mouse model for generation of nAb to neutralization-resistant circulating HIV strains. No such NAbs were induced, as mouse Abs targeted the bottom of soluble Env trimers, suggesting that the glycan shield of Env trimers is impenetrable to murine B cell receptors and that epitopes at the trimer base should be obscured in immunogen design in order to avoid non-nAb responses. Association and dissociation of known anti-trimer bNAbs (VRC01, PGT121, PGT128, PGT151, PGT135, PG9, 35O22, 3BC315 and PGT145) were found to be far greater than murine generated non-NAbs. Hu2015
PG9: A comprehensive antigenic map of the cleaved trimer BG505 SOSIP.664 was made by bNAb cross-competition. Epitope clusters at the CD4bs, quaternary V1/V2 glycan, N332-oligomannose patch and new gp120-gp41 interface and their interactions were delineated. Epitope overlap, proximal steric inhibition, allosteric inhibition or reorientation of glycans were seen in Ab cross-competition. Thus bNAb binding to trimers can affect surfaces beyond their epitopes. PG9, PG16 and PG145, all V1/V2 glycan trimer apex bNAbs, were strongly, reciprocally competitive with one another. V3 glycan bNAbs PGT121, PGT122, PGT123 inhibited binding of PG9 strongly, but in a non-reciprocal manner. Derking2015 (antibody interactions, neutralization, binding affinity, structure)
PG9: Two clade C recombinant Env glycoprotein trimers, DU422 and ZM197M, with native-like structural and antigenic properties involving epitopes against all known classes of bNAbs, were produced and characterized. These Clade C trimers (10-15% of which are in a partially open form) were more like B41 Clade B trimers which have 50-75% trimers in the partially open configuration than like B505 Clade B trimers, almost 100% in the closed, prefusion state. The Clade C trimers are weakly reactive with the V1/V2 glycan bNAb, PG9, and while neutralization of the DU422 pseudotyped virus is robust, that of the ZM197M pseudovirus is moderate. Julien2015 (assay or method development, structure)
PG9: HIV-1 escape from the N332-glycan dependent bNAb, PGT135, developed in an elite controller but without change to the PGT135-binding Env epitope itself. Instead an insertion increasing V1 length by up to 21 residues concomitant with an additional 1-3 glycans and 2-4 cysteines shields the epitope from PGT135. The majority of viruses tested developed a 14-fold resistance to PGT135 from month 7 to 11. In comparison, no significant difference in HIV-1 against bNAb PG9 was seen. vandenKerkhof2016 (elite controllers, neutralization, escape)
PG9: A new trimeric immunogen, BG505 SOSIP.664 gp140, was developed that bound and activated most known neutralizing antibodies but generally did not bind antibodies lacking neuralizing activity. This highly stable immunogen mimics the Env spike of subtype A transmitted/founder (T/F) HIV-1 strain, BG505. Anti-V1/V2 glycan bNAb PG9, neutralized BG505.T332N, the pseudoviral equivalent of the immunogen BG505 SOSIP.664 gp140, and was shown to recognize and bind the immunogen too. Sanders2013 (assay or method development, neutralization, binding affinity)
PG9: This review discusses an array of methods to engineer more effective bNAbs for immunotherapy. Antibody PG9 was mentioned as an example of engineering through rational mutations; PG9-N100(F)Y stabilizes the CDR-H3 in the active conformation, thus improving neutralization. Hua2016 (immunotherapy, review)
PG9: Site-specific analysis of N-glycosylation sites of a soluble recombinant trimerBG505 SOSIP.664 is presented. Neutralization profiles for V1V2 Ab, PG9, to multiple epitopes were determined. Removing the N156 or N160 glycans from either of the BG505 test viruses reduced the neutralization activities of PG9. Behrens2016 (antibody binding site, glycosylation)
PG9: A mathematical model was developed to predict the Ab concentration at which antibody escape variants outcompete their ancestors, and this concentration was termed the mutant selection window (MSW). The MSW was determined experimentally for 12 pairings of diverse HIV strains against 7 bnAbs (b12, 2G12, PG9, PG16, PGT121, PGT128, 2F5). The neutralization of of PG9 was assayed against 5 resistant and 5 sensitive strains. Magnus2016 (neutralization, escape)
PG9: A panel of Env-specific mAbs was isolated from 6 HIV1-infected lactating women. Antibodies in colostrum may help prevent mucosal infection of the infant, so this study aimed to define milk IgGs for future vaccination strategies to reduce HIV transmission during lactation. Despite the high rate of VH_1-69 usage among colostrum Env specific B cells, it did not correlate with distinct gp120 epitope specificity or function. PG9 was compared to the newly-derived mAbs; it had no cross-reactivity with gut bacteria, and tested negative in two tests of autoreactivity. Jeffries2016 (antibody polyreactivity)
PG9: The study detailed binding kinetics of the interaction between BG505 SOSIP.664 trimer or its variants (gp120 monomer; first study of disulfide-stabilized variant gp120-gp41_ECTO protomer) and several mAbs, both neutralizing (VRC01, PGV04, PG9, PG16, PGT121, PGT122, PGT123, PGT145, PGT151, 2G12) and non-neutralizing (b6, b12, 14e, 19b, F240). V1V2 quarternary-dependent epitope-binding bNAb, PG9, bound trimer best, but less well to protomer and BG505 gp120's monomer. Yasmeen2014 (antibody binding site, assay or method development)
PG9: Neutralization breadth in 157 antiretroviral-naive individuals infected for less than 1 year post-infection was studied and compared to a cohort of 170 untreated chronic patients. A range of neutralizing activities was observed with a panel of six recombinant viruses from five different subtypes. Some sera were broadly reactive, predominantly targeting envelope epitopes within the V2 glycan-dependent region. The Env neutralization breadth was positively associated with time post infection. PG9 has been used as a control in detection of glycan-dependent HIV-1 neutralizing sera. Sanchez-Merino2016 (neutralization, acute/early infection)
PG9: A new, current, mostly tier2 panel of 200 C-clade Env-psuedotyped viruses from early (< 100d) infection in southern Africa was used to assess antibody responses to natural infection and to vaccines. Viruses were assayed with bNAbs targeting the V2 glycan (PG9, VRC26.25), the MPER site (4E10), the CD4 binding site (VRC01), and the V3/C3 glycan site (PGT128). For 4E10 (and all other Abs besides PGT128) there was no significant difference in neutralization between pre-seroconversion and post-seroconversion viruses. Viruses collected pre-seroconversion were more resistant to neutralization by serum than those post-seroconversion. As the epidemic matured over 13 years, viruses also became more resistant to mAbs tested. Rademeyer2016 (assay or method development, neutralization)
PG9: The sequential development of three distinct bnAb responses within a single host, CAP257, over 4.5 years of infection has been described. It showed how escape from the first wave of Abs targeting V2 exposed a second site that was the stimulus for a new wave of glycan dependent bnAbs against the CD4 binding site. These data highlighted how Ab evolution in response to viral escape mutations served to broaden the host immune response to two epitopes. A third wave of neutralization targeting an undefined epitope that did not appear to overlap with the four known sites of vulnerability on the HIV-1 envelope has been reported. These data supported the design of templates for sequential immunization strategies. Wibmer2013 (escape)
PG9: This study examined the neutralization of group N, O, and P primary isolates of HIV-1 by diverse antibodies. Cross-group neutralization was observed only with the bNAbs targeting the N160 glycan-V1/V2 site. Four group O isolates, 1 group N isolate, and the group P isolates were neutralized by PG9 and/or PG16 or PGT145 at low concentrations. None of the non-M primary isolates were neutralized by bNAbs targeting other regions, except 10E8, which weakly neutralized 2 group N isolates, and 35O22 which neutralized 1 group O isolate. Bispecific bNAbs (PG9-iMab and PG16-iMab) very efficiently neutralized all non-M isolates with IC₅₀ below 1 ug/mL, except for 2 group O strains. Anti V1/V2 bNAb PG9 was able to neutralize 5/16 tested non-M primary isolates at an IC₅₀< 10µg/ml, 2 of them highly with a value under 1 µg/ml and 3 moderately. Morgand2015 (neutralization, subtype comparisons)
PG9: The neutralization of 14 bnAbs was assayed against a global panel of 12 or 17 Env pseudoviruses. From IC₅₀, IC₈₀, IC₉₀, and IC₉₉ values, the slope of the dose-response curve was calculated. Each class of Ab had a fairly consistent slope. Neutralization breadth was strongly correlated with slope. An IIP (Instantaneous Inhibitory Potential) value was calculated, based on both the slope and IC50, and this value may be predictive of clinical efficacy. PG9, a V2-glycan bnAb belonged to a group with slopes <1. Webb2015 (neutralization)
PG9: This study evaluated the binding of 15 inferred germline (gl) precursors of bNAbs that are directed to different epitope clusters, to 3 soluble native-like SOSIP.664 Env trimers - BG505, B41 and ZM197M. The trimers bound to some gl precursors, particularly those of V1V2-targeted Abs. These trimers may be useful for designing immunogens able to target gl precursors. V1/V2 apex-binding gl-PG9 precursor bound to 2/3 trimers, BG505 and ZM197M. Sliepen2015 (binding affinity, antibody lineage)
PG9: Computational modeling was used to examine antibody recognition of glycans, using a V1V2 bNAb (PG9) and a V3 bnAb (PGT128). Both PG9 and PGT128 have a long CDR H3 loop that can penetrate the glycan shield and form interactions with gp120. The modeling results showed that the tip of the CDR H3 loop is flexible in the free antibodies and is able to move within the bound conformation, which likely increases the penetrability of the glycan shield. Qi2016 (glycosylation)
PG9: To test whether NAbs can inhibit viral transmission through mucosal tissue, 4 bNAbs (PG9, PG16, VRC01, 4E10) were tested in tissue culture models of human colonic and ectocervical tissues. All 4 nAbs reduced HIV transmission, with a relative efficacy of PG16 > PG9 > VRC01 >> 4E10. The nAbs had a good safety profile and were not affected by the presence of semen. Scott2015 (immunotherapy)
PG9: The study's goal was to produce modified SOSIP trimers that would reduce the exposure - and, by inference, the immunogenicity - of non-NAb epitopes such as V3. The binding of several modified SOSIP trimers was compared among 12 neutralizing (PG9, PG16, PGT145, PGT121, PGT126, 2G12, PGT135, VRC01, CH103, CD4, IgG2, PGT151, 35O22) and 3 non-neutralizing antibodies (14e, 19b, b6). The V3 non-NAbs 447-52D, 39F, 14e, and 19b bound less well to all A316W variant trimers compared to wild-type trimers. Mice and rabbits immunized with modified, stabilized SOSIP trimers developed fewer V3 Ab responses than those immunized with native trimers. deTaeye2015 (antibody binding site)
PG9: Deep-sequencing and computational methods were used to identify HCDR3 sequences in HIV-naïve donors that mediated binding and neutralization of HIV by mimicking the bnAb PG9 long HCDR3 region when expressed in the context of the rest of the PG9 antibody sequence. 2 naturally occurring HCDR3 sequences from 2 different donors of 70 studied were predicted to adopt a PG9-like hammerhead conformation and were able to bind and neutralize PG9-susceptible viruses. In addition, computational design was used to mimic the process of maturation by somatic mutation of HCDR3 sequences from the HIV-1–naïve repertoire that were predicted to adopt a PG9-like hammerhead conformation. Two to seven mutations in eight different HCDR3 sequences facilitated neutralization of HIV when grafted on a PG9 Ab background. Willis2016 (antibody lineage)
PG9: HIV-1 strains were isolated from 60 patients infected with CRFs 01_AE, 07_BC, and 08_BC. Eight CRF01 strains that produced high-titer Env pseudoviruses were studied further. All were sensitive to neutralization by VRC01, PG9, PG16, and NIH45-46, but insensitive to 2G12. The PG9 have affinity for epitopes located in the conserved regions of the V2-V3 loop. Binding of PG9 and PG16 with the virus was largely dependent on the same residues, although PG16 was more sensitive to V3 loop substitutions than PG9. Sequence analysis of PG9- and PG16-resistant viruses revealed complex mutation patterns associated with residues that are critical for PG9/PG16 binding. CNAE14 was shown to be resistant to both PG9 and PG16. It is likely that substitutions S158T, S162T, K305T, and I307T jointly contribute to this resistance phenotype. Chen2016 (neutralization, subtype comparisons)
PG9: A large cross-sectional study of sera from 205 ART-naive patients infected with different HIV clades was tested against a panel of 219 cross-clade Env-pseudotyped viruses. Their neutralization was compared to the neutralization of 10 human bNAbs (10E8, 4E10, VRC01, PG9, PGT145, PGT128, 2F5, CH01, b12, 2G12) tested with a panel of 119 Env-pseudotyped viruses. Results from b12 and 2G12 suggested that these bnAbs may not be as broadly neutralizing as previously thought. PG9 neutralized 86% of the 199 viruses tested. Hraber2014 (neutralization)
PG9: The study compared binding and neutralization of 4 V2 apex bnAbs (PG9, CH01, PGT145, and CAP256.VRC26.09). All recognized a core epitope on V1/V2 (the N-linked glycan at N160 and cysteine-linked lysine rich, HXB2:126-196), which includes residue N160 as well as N173. The lysine rich region on strand C of HIV-1 V2 that is key for binding to the nAb contains the sequence (168)KKQK(171). Inferred germline versions of three of the prototype bnAbs were able to neutralize specific Env isolates. Soluble Env derived from one of these isolates was shown to form a well-ordered Env trimer that could serve as an immunogen to initiate a V2-apex bnAb response. Escape from bnAb PG9 was seen in patient Donor_64 by mutations K169T and K171E. 99% amino acid sequence identity exists between PG9 and CAP256.09 in VH-germline gene. Andrabi2015 (antibody binding site, neutralization, vaccine antigen design, escape, antibody lineage)
PG9: Double, triple or quadruple combinations of fifteen bNAbs that target 4 distinct epitope regions: the CD4 binding site (3BNC117, VRC01, VRC07, VRC07-523, VRC13), the V3-glycan supersite (10–1074, 10-1074V, PGT121, PGT128), the V1/V2-glycan site (PG9, PGT145, PGDM1400, CAP256-VRC26.08, CAP256-VRC26.25), and the gp41 MPER epitope (10E8) were studied. Their neutralization potency and breadth were assayed against a panel of 200 acute/early subtype C strains, and compared to a novel, highly accurate predictive mathematical model (no-overlap Bliss Hill model, CombiNaber tool, LANL HIV Immunology database). These data were used to predict the best combinations of bNAbs for immunotherapy. Wagh2016 (neutralization, immunotherapy)
PG9: An atomic-level understanding of V1V2-directed bNAb recognition in a donor was used in the design of V1V2 scaffolds capable of interacting with quaternary-specific V1V2-directed bNAbs. The cocrystal structure of V1V2 with antibody CH03 from a second donor is reported and Env interactions of antibody CAP256-VRC26 from a third donor are modeled. V1V2-directed bNAbs used strand-strand interactions between a protruding Ab loop and a V1V2 strand but differed in their N-glycan recognition. Ontogeny analysis indicated that protruding loops develop early, and glycan interactions mature over time. Combination of the atomic-level information and negative-stain EM of PG9 in complex with a soluble trimeric Env mimic, BG505 SOSIP.664, suggest that the quaternary dependency of PG9 arises from its recognition of glycan N160 from a neighboring protomer24. Gorman2016 (glycosylation, structure, antibody lineage)
PG9: The human Ab gene repertoires of uninfected and HIV-1-infected individuals were studied at genomic DNA (gDNA) and cDNA levels to determine the frequencies of putative germline Ab genes of known HIV-1 bnAbs. All libraries were deep sequenced and analysed using IMGT/HighV-QUEST software (http://imgt.org/HighV-QUEST/index. The human gDNA Ab libraries were more diverse in heavy and light chain V-gene lineage usage than the cDNA libraries. This implied that the human gDNA Ab gene repertoires may have more potential than the cDNA repertoires to develop HIV-1 bnmAbs. Relatively high frequencies of the VH and VKs and VLs that used the same V-genes and had the same CDR3 lengths as known HIV-1 bnmAbs regardless of (D)J-gene usage. Frequencies of the VLs with the identical VJ recombinations to PG9 were relatively high. The putative germline genes were determined for a set of mAbs (b12, VRC01, VRC03, NIH45-46, 3BNC60, PG9, PGT127, and X5). Zhang2013 (antibody lineage, germline)
PG9: Galactosyl ceramide (Galcer), a glycosphingolipid, is a receptor for the HIV-1 Env glycoprotein. This study has mimicked this interaction by using an artificial membrane containing synthetic Galcer and recombinant HIV-1 Env proteins to identify antibodies that would block the HIV-1 Env-Galcer interaction. HIV-1 ALVAC/AIDSVAX vaccinee-derived MAbs specific for the gp120 C1 region blocked Galcer binding of a transmitted/founder HIV-1 Env gp140. The antibody-dependent cellular cytotoxicity-mediating CH38 IgG and its natural IgA isotype were the most potent blocking antibodies. PG9 exhibited moderate Env-Galcer blocking. Dennison2014 (ADCC, antibody binding site, antibody interactions, glycosylation)
PG9: A unified convergent strategy for the rapid production of bi-, tri-, and tetra-antennary complex type N-glycans with and without terminal N-acetylneuraminic acid residues connected via the α-2,6 or α-2,3 linkages is reported which may facilitate the design of carbohydrate-based immunogens. A glycan microarray-based profiling of PG9 was used to understand the binding specificity. No detectable binding for PG9, probably due to (1) very weak binding affinity toward protein/peptide free glycans, (2) the requirement of closely spaced Man5GlcNAc2 (N160) and complex type glycan (N156/163) as PG9 epitopes, and (3) the heterogeneous distribution of NHS groups on glass slides resulting in uneven and low-density glycan arrays. Shivatare2013 (glycosylation, structure)
PG9: The effect of PNGS on viral infectivity and antibody neutralization (2F5, 4E10, b12, VRC01, VRC03, PG9, PG16, 3869) was evaluated through systemic mutations of each PNGS on CRF07_BC strain. Mutations at N197 (C2), N301 (V3), N442 (C4), and N625 (gp41) rendered the virus more susceptible to neutralization by MAbs that recognize the CD4 binding site or gp41. Generally, mutations on V4/V5 loops, C2/C3/C4 regions, and gp41 reduced the neutralization sensitivity to PG16. However, mutation of N289 (C2) made the virus more sensitive to both PG9 and PG16. Mutations at N142 (V1), N355 (C3) and N463 (V5) conferred resistance to neutralization by anti-gp41 MAbs. Available structural information of HIV Env and homology modeling was used to provide a structural basis for the observed biological effects of these mutations. Wang2013 (neutralization, structure)
PG9: Incomplete neutralization may decrease the ability of bnAbs to protect against HIV exposure. In order to determine the extent of non-sigmoidal slopes that plateau at <100% neutralization, a panel of 24 bnMAbs targeting different regions on Env was tested in a quantitative pseudovirus neutralization assay on a panel of 278 viral clones. All bNAbs had some viruses that they neutralized with a plateau <100%, but those targeting the V2 apex and MPER did so more often. All bnMAbs assayed had some viruses for which they had incomplete neutralization and non-sigmoidal neutralization curves. bNAbs were grouped into 3 groups based on their neutralization curves: group 1 antibodies neutralized more than 90% of susceptible viruses to >95% (PGT121-123, PGT125-128, PGT136, PGV04); group 2 was less effective, resulting in neutralization of 60-84% of susceptible viruses to >95% (b12, PGT130-131, PGT135, PGT137, PGT141-143, PGT145, 2G12, PG9); group 3 neutralized only 36-60% of susceptible viruses to >95% (PG16, PGT144, 2F5, 4E10). McCoy2015 (neutralization)
PG9: The neutralization abilities of Abs were enhanced by bioconjugation with aplaviroc, a small-molecule inhibitor of virus entry into host cells. Diazonium hexafluorophosphate was used. The conjugated Abs blocked HIV-1 entry through two mechanisms: by binding to the virus itself and by blocking the CCR5 receptor on host cells. Chemical modification did not significantly alter the potency and the pharmacokinetics. The PG9-aplaviroc conjugate was tested against a panel of 117 HIV-1 strains and was found to neutralize 100% of the viruses. PG9-aplaviroc conjugate IC50s were lower than those of PG9 in neutralization studies of 36 of the 117 HIV-1 strains. Gavrilyuk2013 (neutralization)
PG9: This study investigated the immunogenicity of three ΔV1V2 deleted variants of the HIV-1 Env protein. The mutant ΔV1V2.9.VK induced a prominent response directed to epitopes effectively bound and neutralized the ΔV1V2 Env virus. This Env variant efficiently neutralized tier 1 virus SF162.This did not result in broad neutralization of neutralization-resistant virus isolates. BG505 SOSIP.664 trimers bind very efficiently to quaternary structure dependent, broadly neutralizing PG9 against the V1V2 domain. Bontjer2013 (vaccine antigen design, structure)
PG9: This review surveyed the Vectored Immuno Prophylaxis (VIP) strategy, which involves passive immunization by viral vector-mediated delivery of genes encoding bnAbs for in vivo expression. Recently published studies in humanized mice and macaques were discussed as well as the pros and cons of VIP towards clinical applications to control HIV endemics. Yang2014 (immunoprophylaxis, review, antibody gene transfer)
PG9: The ability of bNAbs to inhibit the HIV cell entry was tested for b12, VRC01,VRC03, PG9, PG16, PGT121, 2F5, 10E8, 2G12. Among them, PGT121, VRC01, and VRC03 potently inhibited HIV entry into CD4+ T cells of infected individuals whose viremia was suppressed by ART. Chun2014 (immunotherapy)
PG9: Pairwise combinations of 6 NAbs (4E10, 2F5, 2G12, b12, PG9, PG16) were tested for neutralization of pseudoviruses and transmitted/founder viruses. Each of the NAbs tested targets a different region of gp120 or gp41. Some pairwise combinations enhanced neutralization synergistically, suggesting that combinations of NAbs may enhance clinical effectiveness. Miglietta2014 (neutralization)
PG9: The infectious virion (iVirions) capture index (IVCI) of different Abs have been determined. bnAbs captured higher proportions of iVirions compared to total virus particles (rVirions) indicating the capacity, breadth and selectively of bnAbs to capture iVirions. IVCI was additive with a mixture of Abs, providing proof of concept for vaccine-induced effect of improved capacity. bnAb PG9 showed significantly high IVCI and captured 100% of CRF01_A/E infectious virions AE.92TH023 and AE.CM244, as well as subtype B MN virus. Liu2014 (binding affinity)
PG9: Study evaluated 4 gp140 Env protein vaccine immunogens derived from an elite neutralizer donor VC10042, an HIV+ African American male from Vanderbilt cohort. Env immunogens, VC10042.05, VC10042.05RM, VC10042.08 and VC10042.ela, elicited high titers of cross-reactive Abs recognizing V1/V2 regions. PG9 exhibited very weak binding with trimeric VC10042.ela and moderate binding with monomeric form of all 4 immunogens. Carbonetti2014 (elite controllers, vaccine-induced immune responses)
PG9: The study compared various factors affecting the accessibility of epitopes for antibodies targeting the V2 integrin (V2i) region, versus the V3 region. CD4 treament of BaL and JRFL pseudoviruses increased their neutralization sensitivity to V3 MAbs, but not to V2i MAbs. Viruses grown in a glycosidase inhibitor were more sensitive to neutralization by V3, but not V2i, MAbs. Increasing the time of virus-MAb interaction increased virus neutralization by some V2i MAbs and all V3 MAbs. The structural dynamics of V2i and V3 epitopes has important effects in neutralization. Some experiments also included V2p antibodies CH58, CH59, and PG9 for comparison. Upadhyay2014 (glycosylation, neutralization)
PG9: A gp140 trimer mosaic construct (MosM) was produced based on M group sequences. MosM bound to CD4 as well as multiple bNAbs, including VRC01, 3BNC117, PGT121, PGT126, PGT145, PG9 and PG16. The immunogenicity of this construct, both alone and mixed together with a clade C Env protein vaccine, suggest a promising approach for improving NAb responses. Nkolola2014 (vaccine antigen design)
PG9: Cross-group neutralization of HIV-1 isolates from groups M, N, O, and P was tested with diverse patient sera and bNAbs PG9, PG16, 4E10, b12, 2F5, 2G12, VRC01, VRC03, and HJ16. The primary isolates displayed a wide spectrum of sensitivity to neutralization by the human sera, with some cross-group neutralization clearly observed. Among the bNAbs, only PG9 and PG16 showed any cross-group neutralization. The group N prototype strain YBF30 was highly sensitive to neutralization by PG9, and the interaction between their key residues was confirmed by molecular modeling. The conservation of the PG9/PG16 epitope within groups M and N suggests its relevance as a vaccine immunogen. Braibant2013 (neutralization, variant cross-reactivity)
PG9: The V2 region where PG9, an anti-V1V2 bNAb binds exists as a beta-strand. Haynes2013 (review)
PG9: PG9 was one of 10 MAbs used to study chronic vs. consensus vs. transmitted/founder (T/F) gp41 Envs for immunogenicity. Consensus Envs were the most potent eliciters of response but could only neutralize tier 1 and some tier 2 viruses. T/F Envs elicited the greatest breadth of NAb response; and chronic Envs elicited the lowest level and narrowest response. This V1V2 conformational loop binding Nab bound well at <10 nM to 3/5 chronic Envs, 2/6 Consensus Envs and 2/7 T/F Envs. Liao2013c (antibody interactions, binding affinity)
PG9: Design, synthesis and antigenic evaluation of novel cyclic V1V2 glycopeptides carrying defined N-linked glycans, N160 and N156/N173 has been reported in terms of PG9 and PG16 binding and neutralization. A Man₅GlcNAc₂ glycan at N160 and a sialyted N-glycan are crtical for antigen binding. Amin2013 (glycosylation)
PG9: Binding properties of a synthesized V1V2 glycopeptide immunogen that selectively targets bnAbs' naive B cells is reported. The unmutated common ancestor (UCA) of PG9 showed nanomolar affinity to V1V2 bearing Man₅GlcNAc₂ glycan units. Binding of PG9 was undetectable however in the absence of the V2 backbone peptide suggesting a very weak binding affinity to oligomannose glycan alone. Disulfide-linked dimer formation was also required for PG9 binding to V1V2. Alam2013
PG9: PG9 in combination with NAbs NH45-46m2 and NIH46-42m7 was able to control viremia as well as to reduce routes to escape of YU-2 HIV-1. Diskin2013
PG9: This study showed that the inability of Env to elicit the production of broadly neutralizing Abs is due to the inability of diverse Env to engage the germ line B cell receptor forms of known bNAbs. PG9 showed binding to 61% of the recombinant Envs tested including 7 out of 17 clade B Envs, 11 of 16 clade C Envs, 6 of 7 clade A Envs and the gp120 form of A/E A244 Env. The predicted germ line version of PG9 did not exhibit any detectable binding against these Envs. Ca²⁺ influx through the PG9 BCR was also tested as a function of binding affinity. McGuire2014 (antibody interactions, antibody lineage)
PG9: The neutralization profile of 1F7, a human CD4bs mAb, is reported and compared to other bnNAbs. 1F7 exhibited extreme potency against primary HIV-1, but limited breadth across clades. PG9 neutralized 83% of a cross-clade panel of 157 HIV-1 isolates (Fig. S1) while 1F7 neutralized only 20% of the isolates. Gach2013 (neutralization)
PG9: This study reports the development of a new cell-line (A3R5)-based highly sensitive Ab detection assay. This T-lymphoblastoid cell-line stably expreses CCR5 and recognizes CCR5-tropic circulating strains of HIV-1. A3R5 cells showed greater neutralization potency compared to the current cell-line of choice TZM-bl. PG9 was used as a reference Ab in neutralization assay comparing A3R5 and TZM-bl. McLinden2013 (assay or method development)
PG9: A highly conserved mechanism of exposure of ADCC epitopes on Env is reported, showing that binding of Env and CD4 within the same HIV-1 infected cell effectively exposes these epitopes. The mechanism might explain the evolutionary advantage of downregulation of cell surface CD4v by the Vpu and Nef proteins. PG9 was used in CD4 coexpression and competitive binding assay. Veillette2014 (ADCC)
PG9: Clade A Env sequence, BG505, was identified to bind to bNAbs representative of most of the known NAb classes. This sequence is the best natural sequence match (73%) to the MRCA sequence from 19 Env sequences derived from PG9 and PG16 MAbs' donor. A point mutation at position L111A of BG505 enabled more efficient production of a stable gp120 monomer, preserving the major neutralization epitopes. The antisera produced by this adjuvanted formulation of gp120 competed with bnAbs from 3 classes of non-overlapping epitopes. PG9 showed very high neutralization titer against BG505 pseudovirus in a competitive binding assay as shown in Table 1. Env sequence from PG9 donor showed potential N glycosylation (PNG) sites at position 160 and 156, suggesting that a substitution at one of these sites is not the primary cause of neutralization resistance to PG9 (Table 4). This emphasizes that the BG505 L111Agp120 immunogen can elicit a robust Ab response to PG9. Hoffenberg2013 (antibody interactions, glycosylation, neutralization)
PG9: High affinity binding of PG9 with a soluble SOSIP.664 gp140 trimer constructed from the Clade A BG505 sequence was demonstrated. This enabled structural and biophysical characterization of the PG9:Env trimer complex. Electron microscopy (EM) and other assays indicate that only a single PG9-Fab binds to the Env trimer. EM reconstruction also demonstrated that PG9 recognized the trimer asymmetrically at its apex via contact with 2 of the 3 gp120 protomers. In addition to N156 and N160 glycan interactions with a scaffolded V1/V2 domain, PG9 also makes secondary interactions with an N160 glycan from an adjacent gp120 protomer in the Ab-trimer complex. A glycan mutation to PG9 caused a >10fold reduction of Fab affinity for the BG505 SOSIP.664 gp 140 trimer reflecting adverse effects on trimer binding and virus neutralization. PG9 recognized glycosylated Env proteins with much higher affinity compared to non-glycosylated ones. Julien2013 (antibody interactions, glycosylation, structure)
PG9: To focus immune responses to sites of NAb vulnerability while avoiding immune-evasion by the rest of Env, MPER, V1/V2, and V3 glycan sites were transplanted onto algorithm-identified acceptor scaffolds (proteins with a backbone geometry that recapitulates the antigenicity of the transplanted site). The V1/V2-transplant was not successful in eliciting a robust PG9 response. Zhou2014 (vaccine antigen design)
PG9: This is a review of identified bNAbs, including the ontogeny of B cells that give rise to these antibodies. Breadth and magnitude of neutralization, unique features and similar bNAbs are listed. PG9 is a V1/V2-directed Ab, with breadth 70%, IC₅₀ 0.31 μg per ml, and its unique feature is its extended CDR H3, which is often tyrosine-sulfated. Similar MAbs include PG16 and CH01-04. Kwong2013 (review)
PG9: 8 bNAbs (PGT151 family) were isolated from an elite neutralizer. The new bNAbs bind a previously unknown glycan-dependent epitope on the prefusion conformation of gp41. These MAbs are specific for the cleaved Env trimer and do not recognize uncleaved Env trimer. PGT151 family Abs showed 1 log higher neutralization potency than PG9. Falkowska2014
PG9: A statistical model selection method was used to identify a global panel of 12 reference Env clones among 219 Env-pseudotyped viruses that represent the spectrum of neutralizing activity seen with sera from 205 chronically HIV-1-infected individuals. This small final panel was also highly sensitive for detection of many of the known bNAbs, including this one. The small panel of 12 Env clones should facilitate assessments of vacine-elicited NAbs. Decamp2014 (assay or method development)
PG9: The conserved central region of gp120 V2 contains sulfated tyrosines (Tys173 and Tys177) that in the CD4-unbound prefusion state mediate intramolecular interaction between V2 and the conserved base of the third variable loop (V3), functionally mimicking sulfated tyrosines in CCR5 and anti-coreceptor-binding-site antibodies such as 412d. Enhancement of tyrosine sulfation decreased binding and neutralization of HIV-1 BaL by monomeric sCD4, 412d, and anti-V3 antibodies and increased recognition by the trimer-preferring antibodies PG9, PG16, CH01, and PGT145. Conversely, inhibition of tyrosine sulfation increased sensitivity to soluble CD4, 412d, and anti-V3 antibodies and diminished recognition by trimer-preferring antibodies. These results identify the sulfotyrosine-mediated V2-V3 interaction as a critical constraint that stabilizes the native HIV-1 envelope trimer and modulates its sensitivity to neutralization. Cimbro2014
PG9:X-ray crystallography, surface plasmon resonance and pseudovirus neutralization were used to characterize a heavy chain only llama antibody, named JM4. The full-length IgG2b version of JM4 neutralizes over 95% of circulating HIV-1 isolates. JM4 targets a hybrid epitope on gp120 that combines elements from both the CD4 binding region and the coreceptor binding surface. JM4 IgG2b was able to potently neutralize the HIV-1 isolates that were resistant to PG9. Acharya2013 (neutralization)
PG9: 12 somatically related nAbs were isolated from donor CAP256. All nAbs of CAP256-VRC26 lineage had long CDRH3 regions necessary to penetrate the glycan shield and engage the V1V2 epitope. Both CAP256-VRC26 Abs and PG9 class nAbs showed similarity in recognizing the trimeric V1V2 cap. Unlike PG9, the CAP256-VRC26 Abs were only partially and variably sensitive to loss of glycans at N160 and N156. Doria-Rose2014 (glycosylation)
PG9: This is a review of a satellite symposium at the AIDS Vaccine 2012 conference, focusing on antibody gene transfer. Phil Johnson presented results comparing an immunoadhesin form of the antibody PG9 with the native IgG architecture in which he found that the native IgG architecture had a neutralization potency tenfold greater than that of the immunoadhesin, suggesting that natural antibody architectures are more preferable for further clinical development. Balazs2013 (immunoprophylaxis)
PG9: A computational method to predict Ab epitopes at the residue level, based on structure and neutralization panels of diverse viral strains has been described. This method was evaluated using 19 Env-Abs, including PG9, against 181 diverse HIV-1 strains with available Ab-Ag complex structures. Chuang2013 (computational epitope prediction)
PG9: This study reports the glycan binding specificities and atomic level details of PG16 epitope and somatic mechanisms of clonal antibody diversification. Three PG16 specific residues Arg94_LC,Ser95_LC and His95_LC (RSH) are found to be critical for sialic acid binding on complex glycan. RSH residues were introduced into PG9 to produce a chimeric antibody with enhanced neutralization. The co-crystal structure of PG9 bound to V1-V2 is discussed and compared to PG16 and PG9-PG16-RSH chimeric Ab based on its ability to recognize a combination of N-linked glycans and envelop polypeptide. Pancera2013 (antibody binding site, glycosylation, structure, chimeric antibody)
PG9: Four V2 MAbs CH58, CH59, HG107 and HG120 were isolated from RV144 Thai HIV-1 vaccinees. These MAbs recognized residue 169, neutralized laboratory HIV-1 (tier 1 strains) and mediated ADCC. PG9 was used in the study as a V1-V2 bnAb control to study the binding of the new mAb isolates. While PG9, PG16 and CH01 binding was abrogated by N160K and N156Q mutations and also by native glycosylation, the binding of CH58 and CH59 was not affected. Crystal structures revealed that CH58, CH59, and PG9 recognize overlapping V2 epitopes in dramatically different conformations, ranging from helical to beta strands. Liao2013b (ADCC, structure)
PG9: The complexity of the epitopes recognized by ADCC responses in HIV-1 infected individuals and candidate vaccine recipients is discussed in this review. PG9 is discussed as the V2 region-targeting, anti-gp120 BNAb exhibiting ADCC activity and having a discontinuous epitope. RV144 vaccine induced mAbs CH58 and CH59 also bind to the same region of PG9, but do not display preferential binding to gp120 and don't bind to glycans in position 156 and 160. Pollara2013 (ADCC, review)
PG9: "Neutralization fingerprints" for 30 neutralizing antibodies were determined using a panel of 34 diverse HIV-1 strains. 10 antibody clusters were defined: VRC01-like, PG9-like, PGT128-like, 2F5-like, 10E8-like and separate clusters for b12, CD4, 2G12, HJ16, 8ANC195. Georgiev2013 (neutralization)
PG9: ADCC mediated by CD4i mAbs (or anti-CD4i-epitope mAbs) was studied using a panel of 41 novel mAbs. Three epitope clusters were classified, depending on cross-blocking in ELISA by different mAbs: Cluster A - in the gp120 face, cross-blocking by mAbs A32 and/or C11; Cluster B - in the region proximal to CoRBS (co-receptor binding site) involving V1V2 domain, cross-blocking by E51-M9; Cluster C - CoRBS, cross-blocking by 17b and/or 19e. The ADCC half-maximal effective concentrations of the Cluster A and B mAbs were generally 0.5^-1 log lower than those of the Cluster C mAbs, and none of the Cluster A or B mAbs could neutralize HIV-1. Cluster A's A32- and C11-blockable mAbs were suggested to recognize conformational epitopes within the inner domain of gp120 that involve the C1 region. Neutralization potency and breadth were also assessed for these mAbs. No correlation was found between ADCC and neutralization Abs' action or functional responses. Guan2013 (ADCC, antibody interactions)
PG9: This study describes an ˜11 Angstrom cryo-EM structure of the trimeric HIV-1 Env precursor in its unliganded state. The three gp120 and gp41 subunits form a cage like structure with an interior void surrounding the trimer axis which restricts Ab access. crystal structure of PG9 was referred in the context of gp120 V1/V2 binding domains. Mao2012 (structure)
PG9: Emergence and evolution of the earliest cross-reactive neutralizing antibody responses were studied in B clade-infected individual, Two distinct epitopes on Env were targeted. First specificity appeared at 3 years post infection and targeted the CD4-binding site. Second specificity appeared a year later. It was due to PG9-like antibodies, which were able to neutralize those viruses not susceptible to the anti-CD4-BS antibodies in AC053. Mikell2012 (neutralization, rate of progression, polyclonal antibodies)
PG9: Neutralization profiles of 7 bnAbs were analyzed against 45 Envs (A, C, D clades), obtained soon after infection (median 59 days). The transmitted variants have distinct characteristics compared to variants from chronic patients, such as shorter variable loops and fewer potential N-linked glycosylation sites (PNGS). PG9 neutralized 49% of these viruses. Goo2012 (neutralization, rate of progression)
PG9: A computational tool (Antibody Database) identifying Env residues affecting antibody activity was developed. As input, the tool incorporates antibody neutralization data from large published pseudovirus panels, corresponding viral sequence data and available structural information. The model consists of a set of rules that provide an estimated IC₅₀ based on Env sequence data, and important residues are found by minimizing the difference between logarithms of actual and estimated IC₅₀. The program was validated by analysis of MAb 8ANC195, which had unknown specificity. Predicted critical N-glycosylation for 8ANC195 were confirmed in vitro and in humanized mice. The key associated residues for each MAb are summarized in the Table 1 of the paper and also in the Neutralizing Antibody Contexts & Features tool at Los Alamos Immunology Database. West2013 (glycosylation, computational epitope prediction)
PG9: Identification of broadly neutralizing antibodies, their epitopes on the HIV-1 spike, the molecular basis for their remarkable breadth, and the B cell ontogenies of their generation and maturation are reviewed. Ontogeny and structure-based classification is presented, based on MAb binding site, type (structural mode of recognition), class (related ontogenies in separate donors) and family (clonal lineage). This MAb's classification: gp120 V1V2 site, penetrating CDR H3 binds two glycans and strand, PG9 class, PG9 family. Kwong2012 (review, structure, broad neutralizer)
PG9: This review discusses the new research developments in bnAbs for HIV-1, Influenza, HCV. Models of the HIV-1 Env spike and of Influenza visrus spike with select bnAbs bound are shown. Burton2012 (review)
PG9: This review discusses how analysis of infection and vaccine candidate-induced antibodies and their genes may guide vaccine design. This MAb is listed as V1/V2 conformational epitope bnAb, isolated after 2009 by neutralization screening of cultured, unselected IgG+ memory B cells. Bonsignori2012b (vaccine antigen design, vaccine-induced immune responses, review)
PG9: Antigenic properties of 2 biochemically stable and homogeneous gp140 trimers (A clade 92UG037 and C clade CZA97012) were compared with the corresponding gp120 monomers derived from the same percursor sequences. The trimers had nearly all the antigenic properties expected for native viral spikes and were markedly different from monomeric gp120. Both trimers, but not monomers, bound to PG9 and PG16. Kovacs2012 (antibody binding site, neutralization, binding affinity)
PG9: Glycan shield of HIV Env protein helps to escape the Ab recognition. Several of the PGT BnAbs interact directly with the HIV glycan coat. Crystal structures of Fabs PGT127 and PGT128 showed that the high neutralizing potency was mediated by cross-linking Env trimers on the viral surface. PGT128 was compared and referred as an order of magnitude more potent than PG9. Pejchal2011 (glycosylation, structure, broad neutralizer)
PG9: PG9 and PG9-like V1V2-directed MAbs, that require an N-linked glycan at Env 160, were analyzed for gain-of-function mutations. 21 PG9-resistant HIV-1 isolates were analyzed by mutagenesis and neutralization assays. E to K mutations at positions 168, 169, 171 led to the most dramatic improvements on sensitivity to these MAbs (PG9, PG16, CH01, CH04, PGT141, PGT145). Doria-RoseNA2012 (escape)
PG9: The study used the swarm of quasispecies representing Env protein variants to identify mutants conferring sensitivity and resistance to BnAbs. Libraries of Env proteins were cloned and in vitro mutagenesis was used to identify the specific AA responsible for altered neutralization/resistance, which appeared to be associated with conformational changes and exposed epitopes in different regions of gp160. The result showed that sequences in gp41, the CD4bs, and V2 domain act as global regulator of neutralization sensitivity. PG9 was used as BnAb to screen Env clones. wtR clone was weakly sensitive to PG9. ORourke2012 (neutralization)
PG9: Glycan Asn332-targeting broadly cross-neutralizing (BCN) antibodies were studied in 2 C-clade infected women. The ASn332 glycan was absent on infecting virus, but the BCN epitope with Asn332 evolved within 6 months though immune escape from earlier antibodies. Plasma from the subject CAP177 neutralized 88% of a large multi-subtype panel of 225 heterologous viruses, whereas CAP 314 neutralized 46% of 41 heterologous viruses but failed to neutralize viruses that lack glycan at 332. PG9 was referred to have second BCN Ab epitopes at AA 156 and 160 in addition to 332. Moore2012 (neutralization, escape)
PG9: Crystal structures of unliganded core gp120 from HIV-1 clade B, C, and E were determined to understand the mechanism of CD4 binding capacity of unliganded HIV-1. The results suggest that the CD4 bound conformation represents "a ground state" for the gp120 core with variable loop. PG9 was used as a control to prove whether the purified and crystallized gp120 is in the CD4 bound conformational state or not. Kwon2012 (structure)
PG9: Vaccination efficacy of RV144 is described. The authors proposed that RV144 induced antibodies against Env V1/V2. The relationship between vaccine status and V1/V2 sequence have been characterized. The estimated cumulative HIV-1 incidence curve in the vaccine and placebo groups showed immunogenicity for K169 and 1181X genotypes and no immunogenicity for the opposite residues. PG9 was discussed as the quaternary-structure-preferring (QSP) antibody and mutations at positions 169 and 181 were associated with significant alteration in neutralization. Rolland2012 (vaccine-induced immune responses)
PG9: The use of computationally derived B cell clonal lineages as templates for HIV-1 immunogen design is discussed. PG9 has been discussed in terms of immunogenic and functional characteristics of representative HIV-1 BnAbs and their reactions to antigens. Haynes2012 (antibody interactions, memory cells, vaccine antigen design, review, antibody polyreactivity, broad neutralizer)
PG9: Polyclonal B cell responses to conserved neutralization epitopes are reported. Cross-reactive plasma samples were identified and evaluated from 308 subjects tested. PG9 was used as a control mAb in the comprehensive set of assays performed. C1-0763 targeted a region similar to PG9 and PG16 recognizing a V1/V2 loop dependent epitope. Tomaras2011 (neutralization, polyclonal antibodies)
PG9: Several antibodies including 10-1074 were isolated from B-cell clone encoding PGT121, from a clade A-infected African donor using YU-2 gp140 trimers as bait. These antibodies were segregated into PGT121-like (PGT121-123 and 9 members) and 10-1074-like (20 members) groups distinguished by sequence, binding affinity, carbohydrate recognition, neutralizing activity, the V3 loop binding and the role of glycans in epitope formation. PG9 was used as a control. Detail information on the binding and neutralization assays are described in the figures S2-S11. Mouquet2012a (glycosylation, neutralization, binding affinity)
PG9: YU2 gp140 bait was used to characterize 189 new MAbs representing 51 independent IgG memory B cell clones from 3 clade A or B HIV infected patients exhibiting broad neutralizing activity. PG9 was referred to in discussing the efficiency of YU-2 gp140 trimer as a bait for Ab capture. Mouquet2011 (neutralization)
PG9: The rational design of vaccines to elicit broadly neutralizing antibodies to HIV-1 is discussed in relation to understanding of vaccine recognition sites, the structural basis of interaction with HIV-1 env and vaccine developmental pathways. Role of PG9 has been discussed in terms of humoral immune response during HIV1 infection. The vulnerability sites on the viral spike shows quaternary structural constraints, and maps to the second and third variable regions of gp120 (variable loops V2 and V3). PG9 recognizes these regions and neutralizes 70%–80% of current circulating isolates. Kwong2011 (antibody binding site, neutralization, vaccine antigen design, review)
PG9: A panel of glycan deletion mutants was created by point mutation into HIV gp160, showing that glycans are important targets on HIV-1 glycoproteins for broad neutralizing responses in vivo. Enrichment of high mannose N-linked glycan(HM-glycan) of HIV-1 glycoprotein enhanced neutralizing activity of sera from 8/9 patients. PG9 was used as a control to compare the neutralizing activity of patients' sera. Lavine2012 (neutralization)
PG9: Ab-driven escape and Ab role in infection control and prevention are reviewed. Main focus is on NAbs, but Ab acting through effector mechanisms are also discussed. PG9 is discussed in the context of developing broadly cross-neutralizing antibodies. Overbaugh2012 (escape, review)
PG9: Neutralization activity was compared against MAb 10E8 and other broad and potent neutralizers in a 181-isolate Env-pseudovirus panel. PG9 neutralized 78% of viruses at IC50<50 μg/ml and 65% of viruses at IC50<1 μg/ml, compared with 98% and 72% of MAb 10E8, respectively. Huang2012a (neutralization)
PG9: Antigenic properties of undigested VLPs and endo H-digested WT trimer VLPs were compared. Binding to E168K+ N189A WT VLPs was dramatic compared to the parent WT VLPs, uncleaved VLPs. There was no significant correlation between E168K+N189A WT VLP binding and PG9 neutralization, while trimer VLP ELISA binding and neutralization exhibited a significant correlation. BN-PAGE shifts using digested E168K + N189A WT trimer VLPs exhibited prominence compared to WT VLPs. Tong2012 (neutralization, binding affinity)
PG9: Broadly neutralizing antibodies circulating in plasma were studied by affinity chromatography and isoelectric focusing. The Abs fell in 2 groups. One group consisted of antibodies with restricted neutralization breadth that had neutral isoelectric points. These Abs bound to envelope monomers and trimers versus core antigens from which variable loops and other domains have been deleted. Another minor group consisted of broadly neutralizing antibodies consistently distinguished by more basic isoelectric points and specificity for epitopes shared by monomeric gp120, gp120 core, or CD4-induced structures. The pI values estimated for neutralizing plasma IgGs were compared to those of human anti-gp120 MAbs, including 5 bnMAbs (PG9, PG16, VRC01, b12, and 2G12), 2 narrowly neutralizing MAbs (17b and E51), and 3 nonneutralizing MAbs (A32, C11, and 19e). bnMAbs PG9 and PG16 exhibited more-neutral pIs (around 7.8), matching the more-neutral end of the plasma-derived fraction series, showing broadly neutralizing, but not most potent activity. Sajadi2012 (polyclonal antibodies)
PG9: Sensitivity to neutralization was studied in 107 full-length Env molecular clones from multiple risk groups in various locations in China. Neutralization sensitivity to plasma pools and bNAbs was not correlated. PG9 neutralized 81% (25/31) and PG16 neutralized 71% (22/31) of the viruses tested. Viruses insensitive to PG9 were all equally insensitive to PG16 but not the other way around, suggesting that PG9 can tolerate more viral glycoprotein amino acid substitutions than PG16. Shang2011 (glycosylation, neutralization, subtype comparisons)
PG9: The sensitivity to PG9 and PG16 of pseudotyped viruses was analysed carrying envelope glycoproteins from the viral quasispecies of three HIV-1 clade CRF01_AE-infected patients. It was confirmed that an acidic residue or a basic residue at position 168 in the V2 loop is a key element determining the sensitivity to PG9 and PG16. In addition, evidence is provided of the involvement of a conserved residue at position 215 of the C2 region in the PG9/PG16 epitopes. Sensitivity to PG9 in 10 Env-pseudotyped viruses was analyzed. Five clones from case 0377 presented a broad and continuous range of sensitivity to PG9. A broader range of sensitivity was observed in case 0978, clone 0978-M3 being resistant to PG9 whereas two other clones, 0978-M1 and 0978-M2, were highly sensitive. Similarly, two clones from case 0858 displayed peculiar patterns of neutralization: clone 0858-M1 was sensitive to neutralization by PG9 only whereas clone 0858-M2 was resistant to PG9. These results showed the broad heterogeneity in sensitivity to PG9 of closely genetically related envelope glycoproteins derived from single viral quasispecies. Clone 0978-M3 from case 0978 was resistant to PG9, whereas clones 0978-M1/M2 were highly sensitive to PG9. 0978-M3 E168K resulted in a high sensitivity to PG9. In contrast, 0978-M2 K168E conferred resistance to PG9. 0858-M2 M215I conferred sensitivity to PG9, whereas the mutant 0858-M2 M475I remained highly resistant to PG9. I215M diminished the sensitivity of all clones to PG9, except that of clone 5008CL2 for PG9. Thenin2012a (neutralization)
PG9: The interaction of CD4bs-binding MAbs (VRC01, VRC-PG04) and V1V2 glycan-dependent MAbs (PG9, PG16) was analyzed. MAb binding and neutralization studies showed that these two Env targets to not cross-compete and that their combination can mediate additive neutralization. The combination of MAbs VRC01 and PG9 provides a predicted coverage of 97% of 208 isolates at IC50 < 50 μg/ml and of 91% at IC50 < 50 μg/ml. In contrast, the combination of PG9 and PG16 (or the combination of VRC01 and VRC-PG04) was only marginally better than either MAb alone. Doria-Rose2012 (antibody interactions)
PG9: The study showed that alteration between a rare lysine K and a common N-linked glycan at position 160 of HIV-1 gp120 is primarily responsible for toggling between 2909 and PG16/PG9 neutralization sensitivity. These neutralization profiles were mutually exclusive (160K for MAb 2909, 160N for PG16/PG9); there was no case of a virus that was sensitive to both 2909 and PG16/PG9 neutralization. Several more positions were studied: both the PG and 2909 MAbs do not require an asparagine at position 156 for neutralization, both the PG and 2909 antibodies tolerate amino acid variation at position 165, and neither the PG nor the 2909 MAb could tolerate a glutamic acid at position 168. Wu2011a (antibody binding site, escape)
PG9:The reason for natural resistance of a patient Env obtained from plasma of a slow progressing Indian patient to PG9/PG16 MAbs in sharp contrast to its contemporaneous autologous Envs was investigated. Based on the experiments conducted for neutralization and glycosylation, it is suggested that the overall neutralization sensitivity of an Env is the outcome of characteristic molecular features of the V2 loop and neutralization by PG9/16 is balanced by the glycans, net positive charge in β sheet C region of the V2 loop against PG9/16 and possibly the length of the V2 loop. Ringe2012 (glycosylation, neutralization)
PG9: The neutralization activities of IA versus IgG and Fab versions of three broadly neutralizing antibodies: PG9, PG16, and VRC01 was compared to more fully understand the potential trade-offs in vector and construct design. The potential to combine VCR01 and PG9/PG16 activities to produce a single reagent with two gp120 specificities was also explored. In an Env-pseudotyped HIV-1 neutralization assay against a panel of 30 strains, PG9 neutralized 22 strains in IgG form, 18 stains in Fab form, 20 strains in IA form and 10 strains in scFv form. It was found that the PG9, PG16, and VRC01 IAs were severalfold less potent than their IgG forms. West2012 (neutralization)
PG9: The biological properties of 17 Env-pseudotyped viruses derived from variants of mother–infant pairs infected by HIV-1 strains of the CRF01_AE clade were compared, in order to explore their association with the restrictive transmission of the virus. Maternal clones issued from MIPs (mother-infant pairs) 0377, 0978 and 1021 displayed a broad and continuous range of sensitivity to both PG9 and PG16 whereas all infant clones were highly sensitive to both mAbs PG9 and PG16. When the four MIPs were considered in aggregate, infant clones were significantly more sensitive to PG9 and PG16 compared to maternal clones. Thenin2012 (neutralization, mother-to-infant transmission)
PG9: gp120 was cyclically permuted and new N- and C-termini were created within the V1, V3, and V4 loop regions to reduce the length of the linker joining gp120 and M9. Addition of trimerization domains at the V1 loop of cyclic permutants of gp120 resulted in the formation of predominantly trimeric species, which bound CD4 and neutralizing antibodies b12, PG9, and PG16 with higher affinity. Saha2012 (binding affinity)
PG9: The role of envelope expression context and producer cell type was characterized for nine novel replication-competent chimeric HIV-1 isolates from the dominant circulating HIV-1 subtypes in Africa, where most new HIV-1 infections are occurring. Pseudoviruses generated in 293T cells were the most sensitive to antibody neutralization. There was no difference in the neutralization sensitivity of PBMC versus 293T-derived viruses using the MAb PG9. Provine2012 (neutralization)
PG9: Phenotypic activities of a single transmitted/founder (T/F) virus from 24 acute individuals were compared to that of 17 viruses from chronics. There was a trend towards enhanced sensitivity to neutralization by PG9 of T/F Envs compared to chronic Envs. Wilen2011 (neutralization)
PG9: HIV-1 adaptation to neutralization by MAbs VRC01, PG9, PG16 was studied using HIV-1 variants from historic (1985-1989) and contemporary (2003-2006) seroconverters. PG9 neutralized 52% of contemporary viruses at IC50 < 1 μ g/ml. The median IC50s of PG9 for viruses from historical and contemporary seroconverters were not significantly different. There was no clear correlation between the sensitivity to PG9 and presence or absence of certain amino acids, but more mutations were observed in viruses from contemporary seroconverters than from historical ones, and the absence of a potential N-linked glycosylation site at position 160 of V2 coincided with resistance to PG9. Euler2011 (glycosylation, neutralization, escape)
PG9: Using U87 target cells, PGV04 neutralized 88% of 162 viruses, with IC50<50 μm/mg, with U87 target cells compared to 75% neutralized by PG9. The potency of neutralization was comparable. On the 97-virus panel, using TZM-bl target cells, the breadth of neutralization was similar, but PGV04 had increased potency. The neutralization potency of PG9, PG16, VRC01 and PGV04 was approximately 10-fold greater than that of MAbs b12, 2G12, 2F5 and 4E10. Alanine substitutions D279A, I420A and I423A abrogated PGV04 neutralization, but varied in their effects on VRC01, CD4-IgG and b12. Falkowska2012 (neutralization, broad neutralizer)
PG9: Neutralizing antibody repertoires of 4 HIV-infected donors with remarkably broad and potent neutralizing responses were probed. 17 new monoclonal antibodies that neutralize broadly across clades were rescued. All MAbs exhibited broad cross-clade neutralizing activity, but several showed exceptional potency. Although PG9 neutralized 77% of 162 isolates at IC50<50 μg/ml, it was almost 10-fold less potent than several new antibodies PGT 121-123 and 125-128, for which the median antibody concentration required to inhibit HIV activity by 50% or 90% (IC50 and IC90 values) was almost 10-fold lower than that of PG9, VRC01 and PGV04. Walker2011 (neutralization, broad neutralizer)
PG9: Atomic-level structure of V1/V2 in complex with PG9 is reported. Instead of being confounded by the N-linked glycan that shields most of gp120 from immune recognition, PG9 uses N-linked glycan for binding through a mechanism shared by a number of antibodies capable of effective HIV neutralization. The structure shows that the antibody recognizes glycopeptide conjugates and avoids diversity in V1/V2 by making sequence-independent interactions, such as hydrogen bonds. The structure of PG9 is consistent with published mutational data: some residues such as Phe 176 are critical because they form part of the hydrophobic core on the concave face of the V1/V2 sheet. Others form direct contacts: for example, the tyrosine sulphate at residue 100H of PG9 interacts with residue 168 when it is an Arg (strain ZM109) or Lys (strain CAP45), but would be repelled by a Glu (as in strain JR-FL); JR-FL is resistant to neutralization by PG9, but becomes sensitive if Glu 168 is changed to Lys10. V1/V2–PG9 interaction observed in the scaffolded V1/V2–PG9 crystal structures encompasses much of the PG9/PG16 epitope, and the structural integrity of this epitope is sensitive to appropriate assembly of the viral spike. With both CAP45 and ZM109 strains of gp120, the V1/V2 site recognized by PG9 consists primarily of two glycans and a strand. Minor interaction with strand B and with the B–C connecting loop complete the epitope, with the entire PG9-recognized surface of V1/V2 contained within the B–C hairpin. McLellan2011 (antibody binding site, structure)
PG9: CDR H3 domains derived from 4 anti-HIV mAbs, PG16, PG9, b12, E51, and anti-influenza MAb AVF were genetically linked to glycosil-phosphatidylinositol (GPI) attachment signal of decay-accelerating factor (DAF) to determine whether the exceptionally long and unique structure of the CDR H3 subdomain of PG16 is sufficient for epitope recognition and neutralization. Similar degrees of cell surface expression of CDR H3(PG9)/hinge/His tag/DAFs (GPI-CDR H3(PG9)) was observed compared with those of the other GPI-CDR H3 constructs (PG16, AVF, and E51). GPI-CDR H3(PG9) exhibited the same degree of inhibition against 5 representative HIV-1 pseudotypes as that of GPI-CDR H3(PG16 and E51). Liu2011 (neutralization, variant cross-reactivity, structure)
PG9: One Env clone (4–2.J45) obtained from a recently infected Indian patient (NARI-IVC4) had exceptional neutralization sensitivity compared to other Envs obtained at the same time point from the same patient. 4–2.J45 Env expressing M424 showed relative resistance to PG9 over 4–2.J45 expressing I424, wherein comparable sensitivities were found of other Envs to PG9 except YU2, which showed approximately 8 fold increase in neutralization sensitivity to PG9. The indistinctness in PG9/PG16 sensitivities of 4–2.J45 and YU2 Envs expressing M424 was possibly due to some compensatory and conformational changes elsewhere within Env. Ringe2011 (neutralization)
PG9: Several soluble gp140 Env proteins recognized by PG9 and PG16 were identified, and the effect of Env trimerization, the requirement for specific amino acids at position 160 within the V2 loop, and the importance of proper gp120-gp41 cleavage for MAb binding to soluble gp140s were investigated along with whether and how the kinetics of PG9 and PG16 binding to soluble gp140 correlates with the neutralizing potencies of these MAbs. It is reported that the presence of the extracellular part of gp41 on certain gp140 constructs improves the recognition of the PG9 epitope on the gp120 subunit and the trimerization of soluble gp140 may lead to the partial occlusion of the PG9 epitope. PG9 most efficiently recognized modified SF162 Env, SF162K160N of the small number of soluble gp140 Envs tested. The absence of SF162 neutralization by PG9 is the presence of a lysine at position 160 instead of an asparagine. PG16 recognized a smaller number of gp140s tested here than PG9. It is suggested that any structural differences between the virion-associated Env form and the soluble gp140 form have a greater impact on the PG16 epitope than on the PG9 epitope. Davenport2011 (antibody binding site, neutralization, binding affinity, structure)
PG9: The characteristics of HIV-1-specific NAbs were evaluated in 100 breast-fed infants of HIV-1-positive mothers who were HIV-1 negative at birth and they were monitored until age 2. A panel of eight viruses that included variants representative of those in the study region as well as more diverse strains was used to determine the breadth of the infant NAbs. PG9 had low neutralization potency for 2 (QD435.100 M.ENV.A4 and THRO4156.18) out of 8 pseudoviruses in the panel but high for the rest of them. For maternal variants, PG9 had low neutralization potency for 3 (MF535.B1, MJ613.A2 and MK184.E4) out of 12 variants and high for the rest of them. Lynch2011 (neutralization, variant cross-reactivity, mother-to-infant transmission)
PG9: CAP256, an HIV-1 subtype C-infected (and subsequently superinfected) participant enrolled in the CAPRISA Acute Infection cohort was studied. A subset of mutants were tested for neutralization by PG9/PG16 along with neutralization of ConC by CAP256 plasma nAb. The epitope recognized by CAP256 is distinct from but overlaps that of PG9/PG16.Like CAP256 plasma, both PG9 and PG16 were heavily dependent on K169 and somewhat dependent on K171. A V2 mutation (N160A) had a profound affect on PG9 and PG16 but a more moderate affect on CAP256. The adjacent D167N residue also impacted CAP256 neutralization but not PG9/PG16, and a K168A mutation reduced CAP256 neutralization but in fact enhanced the neutralization of ConC by PG9/16. Both PG9/16 and CAP256, in the context of the ConC backbone, were slightly affected by mutations in the V3 loop (I305, I309, and F317) with mild effect on neutralization sensitivity. The I307A mutation affected both PG9/PG16 slightly but had no discernible effect on CAP256 neutralization. Some similarities between CAP256 and PG9/16 neutralization along with significant differences suggest that the epitopes recognized by these Abs overlapped but were not identical. Moore2011 (neutralization)
PG9: The impact of specific changes at distal sites on antibody binding and neutralization was examined on Q461 variants. The changes at position 675 in conjunction with Thr to Ala at position 569 resulted in a dramatic increase in the neutralization sensitivity to some gp41 and gp120 MAbs and plasma but had less effect on the more potent MAb VRC01. There was an increase in VRC01 neutralization sensitivity to viruses with both mutations with intermediate effect for the individual mutants. There was some detectable PG9 neutralization of the variant bearing the T569A mutation alone but PG9 neutralization was not achieved with a change at position 675 only. Lovelace2011 (antibody binding site, neutralization, variant cross-reactivity)
PG9: This review discusses current understanding of Env neutralization by antibodies in relation to epitope exposure and how this insight might benefit vaccine design strategies. This MAb is in the list of current MAbs with notable cross-neutralizing activity. Pantophlet2010 (neutralization, variant cross-reactivity, review)
PG9: This review outlines the general structure of the gp160 viral envelope, the dynamics of viral entry, the evolution of humoral response, the mechanisms of viral escape and the characterization of broadly neutralizing Abs. It is noted that this MAb shows a significant breadth of neutralization across all clades and extraordinary potency. Gonzalez2010 (neutralization, variant cross-reactivity, escape, review)
PG9: This review discusses recent rational structure-based approaches in HIV vaccine design that helped in understanding the link between Env antigenicity and immunogenicity. PG9 was isolated from a clade A infected donor using a high-throughput functional screening approach. This MAb was mentioned in the context of immunogens based on the epitopes recognized by bNAbs. Walker2010a (neutralization, review)
PG9: This review discusses the types of B-cell responses desired by HIV-1 vaccines and various methods used for eliciting HIV-1 inhibitory antibodies that include induction and characterization of vaccine-induces B-cell responses. PG9 was mentioned among new MAbs generated by isolating single Env-specific B cells by either single cell sorting by flow cytometry or from memory B-cell cultures coupled with high-throughput neutralization screening assays of B-cell supernatants. PG9 recognizes conserved regions of the variable loops in gp120 and is potent and broadly reactive against approximately 73-79% of HIV-1 strains. Tomaras2010 (review)
PG9: This review discusses strategies for design of neutralizing antibody-based vaccines against HIV-1 and recent major advances in the field regarding isolation of potent broadly neutralizing Abs. Sattentau2010 (review)
PG9: This review focuses on recent vaccine design efforts and investigation of broadly neutralizing Abs and their epitopes to aid in the improvement of immunogen design. NAb epitopes, NAbs response to HIV-1, isolation of novel mAbs, and vaccine-elicited NAb responses in human clinical trials are discussed in this review. Mascola2010 (review)
PG9: Unlike the MPER MAbs tested, PG9 did not show any Env-independent virus capture in the conventional or in the modified version of the virus capture assay. Leaman2010
PG9: Some of the key challenges for the development of an Ab-based HIV vaccine are discussed, such as challenges in identification of epitopes recognized by broadly neutralizing epitopes, the impact of biological mechanisms in addition to Ab neutralization, and the poor persistence of anti-Env Ab responses in the absence of continuous antigenic stimulation. Lewis2010 (review)
PG9: The role of HIV-1 envelope spike density on the virion and the effect it has on MAb avidity, and neutralization potencies of MAbs presented as different isotypes, are reviewed. Engineering approaches and design of immunogens able to elicit intra-spike cross-linking Abs are discussed. Klein2010 (review)
PG9: Novel techniques for generation of broadly neutralizing Abs and how these Ab can aid in development of an effective vaccine are discussed. Joyce2010 (review)
PG9: The review describes several different methods that have been used to isolate and characterize HIV MAbs within the human Ab repertoire. Relative advantages and limitations of methods such as EBV transformation, human hybridoma, non-immortalized B cell culture, combinatorial libraries from B cells and clonal sorting are discussed. Hammond2010 (review)
PG9: This review summarizes novel techniques recently developed for isolation of broadly neutralizing monoclonal Abs from HIV-infected donors. Future challenges and importance of these techniques for development of HIV vaccines is also discussed. Burton2010 (review)
PG9: PG9 epitope structure is reviewed. This review also summarizes data on the evolution of HIV neutralizing Abs, principles of Env immunogen design to elicit broadly neutralizing Abs, and future critical areas of research for development of an Ab-based HIV vaccine. Hoxie2010 (vaccine antigen design, review)
PG9: Novel methods for generation of broadly neutralizing Abs, such as PG9 and PG16 are reviewed. This review also summarizes PG9 and PG16 MAbs, and their similarity to 2909 MAb. Kwong2009 (review)
PG9: Removal of N-linked glycosylation sites was shown to generally lead to a reduction in neutralization sensitivity to PG9, however, the position of the N-linked glycosylation site removed and the magnitude of the effect was isolate dependent. Loss of glycosylation sites in the V1, V2 and V3 loops had greatest effect on reduced neutralization sensitivity. Removal of the N160 glycan was the only substitution that universally eliminated sensitivity to neutralization by PG9. Binding of PG9 to Env transfected cells and to gp120 was not competed by monosaccharides indicating that PG9 sensitivity to glycosylation was due to the effect of glycans on gp120 conformation and PG9 epitope accessibility. Doores2010 (antibody binding site, glycosylation, neutralization, binding affinity)
PG9: The CDR H3 region was shown critical for neutralization activity of the Ab. Affinity maturation of PG9 correlated with Ab neutralization breadth, as light chain V-gene reversion produced chimeric Abs with less neutralization. N-linked glycosylation of PG9 was not required for neutralization. Fab and IgG formats of PG9 had comparable neutralization potencies. The likely site of PG9 reaction with Env was determined to consist of CDR L1 and L2 and the CDR H3 elements. Pancera2010 (glycosylation, neutralization)
PG9: Broadly neutralizing sera from elite neutralizers exhibited significant sensitivities to mutations I165A, N332A, and N160K. PG9 neutralization activity was tested for pseudoviruses with the mutations relative to the WT. PG9 was shown to require N160K glycosylation for potent neutralizing activity. Pseudoviruses produced in cells treated with kifunensine were found resistant to PG9 neutralization. Donor sera that exhibited sensitivity to N160K showed diminished neutralizing activity against kifunensine-treated pseudoviruses, indicating that PG16 and PG9 MAbs mediate most of the sera neutralizing activity. PG16 and PG9 - like Ab were found in 21% of the donors. Walker2010 (glycosylation, neutralization)
PG9: Crystal structure of PG9 light chain was determined and a homology model of Fab PG9 was constructed for comparison to PG16 MAb. PG9 was shown to have a long CDR H3 that forms a unique stable subdomain. A 7-residue specificity loop within CDR H3 was shown to confer fine specificity of PG16 and PG9 MAbs, and to contain important contacts to gp120 as replacement of the 7 residues abolished PG9 neutralization. CDR H3 tyrosine for PG9 was doubly sulfated, and tyrosine sulfation was shown to play a role in both binding and neutralization. Glycosylation of PG9 light chain did not have a significant effect on neutralization. Pejchal2010 (glycosylation, neutralization, binding affinity, structure)
PG9: This MAb was derived from clade A infected patient. PG9 failed to bind to recombinant gp120 or gp41 but exhibited high neutralization breadth and potency, neutralizing 127 out of 162 cross-clade viruses with a potency exceeding that of b12, 2G12, and 2F5. PG9 also potently neutralized IAVI-C18 virus, that is neutralization resistant to all four bNAbs. PG9 competed for gp120 binding with Abs against V2, V3 and CD4i. N-glycosylation sites N156 and N160 in the V2 region were critical in forming PG9 epitope. PG9 preferred binding to trimeric Env due to subunit presentation in this form. This Ab had a long CDRH3 loop. Walker2009a (antibody generation, glycosylation, neutralization, variant cross-reactivity, binding affinity)

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Bradley2016a Todd Bradley, Ashley Trama, Nancy Tumba, Elin Gray, Xiaozhi Lu, Navid Madani, Fatemeh Jahanbakhsh, Amanda Eaton, Shi-Mao Xia, Robert Parks, Krissey E. Lloyd, Laura L. Sutherland, Richard M. Scearce, Cindy M. Bowman, Susan Barnett, Salim S. Abdool-Karim, Scott D. Boyd, Bruno Melillo, Amos B. Smith, 3rd., Joseph Sodroski, Thomas B. Kepler, S. Munir Alam, Feng Gao, Mattia Bonsignori, Hua-Xin Liao, M Anthony Moody, David Montefiori, Sampa Santra, Lynn Morris, and Barton F. Haynes. Amino Acid Changes in the HIV-1 gp41 Membrane Proximal Region Control Virus Neutralization Sensitivity. EBioMedicine, 12:196-207, Oct 2016. PubMed ID: 27612593. Show all entries for this paper.

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Cimbro2014 Raffaello Cimbro, Thomas R. Gallant, Michael A. Dolan, Christina Guzzo, Peng Zhang, Yin Lin, Huiyi Miao, Donald Van Ryk, James Arthos, Inna Gorshkova, Patrick H. Brown, Darrell E. Hurt, and Paolo Lusso. Tyrosine Sulfation in the Second Variable Loop (V2) of HIV-1 gp120 Stabilizes V2-V3 Interaction and Modulates Neutralization Sensitivity. Proc. Natl. Acad. Sci. U.S.A., 111(8):3152-3157, 25 Feb 2014. PubMed ID: 24569807. Show all entries for this paper.

Crooks2015 Ema T. Crooks, Tommy Tong, Bimal Chakrabarti, Kristin Narayan, Ivelin S. Georgiev, Sergey Menis, Xiaoxing Huang, Daniel Kulp, Keiko Osawa, Janelle Muranaka, Guillaume Stewart-Jones, Joanne Destefano, Sijy O'Dell, Celia LaBranche, James E. Robinson, David C. Montefiori, Krisha McKee, Sean X. Du, Nicole Doria-Rose, Peter D. Kwong, John R. Mascola, Ping Zhu, William R. Schief, Richard T. Wyatt, Robert G. Whalen, and James M. Binley. Vaccine-Elicited Tier 2 HIV-1 Neutralizing Antibodies Bind to Quaternary Epitopes Involving Glycan-Deficient Patches Proximal to the CD4 Binding Site. PLoS Pathog, 11(5):e1004932, May 2015. PubMed ID: 26023780. Show all entries for this paper.

Crooks2018 Ema T. Crooks, Samantha L. Grimley, Michelle Cully, Keiko Osawa, Gillian Dekkers, Kevin Saunders, Sebastian Ramisch, Sergey Menis, William R. Schief, Nicole Doria-Rose, Barton Haynes, Ben Murrell, Evan Mitchel Cale, Amarendra Pegu, John R. Mascola, Gestur Vidarsson, and James M. Binley. Glycoengineering HIV-1 Env Creates `Supercharged' and `Hybrid' Glycans to Increase Neutralizing Antibody Potency, Breadth and Saturation. PLoS Pathog., 14(5):e1007024, May 2018. PubMed ID: 29718999. Show all entries for this paper.

Davenport2011 Thaddeus M. Davenport, Della Friend, Katharine Ellingson, Hengyu Xu, Zachary Caldwell, George Sellhorn, Zane Kraft, Roland K. Strong, and Leonidas Stamatatos. Binding Interactions between Soluble HIV Envelope Glycoproteins and Quaternary-Structure-Specific Monoclonal Antibodies PG9 and PG16. J. Virol., 85(14):7095-7107, Jul 2011. PubMed ID: 21543501. Show all entries for this paper.

Decamp2014 Allan deCamp, Peter Hraber, Robert T. Bailer, Michael S. Seaman, Christina Ochsenbauer, John Kappes, Raphael Gottardo, Paul Edlefsen, Steve Self, Haili Tang, Kelli Greene, Hongmei Gao, Xiaoju Daniell, Marcella Sarzotti-Kelsoe, Miroslaw K. Gorny, Susan Zolla-Pazner, Celia C. LaBranche, John R. Mascola, Bette T. Korber, and David C. Montefiori. Global Panel of HIV-1 Env Reference Strains for Standardized Assessments of Vaccine-Elicited Neutralizing Antibodies. J. Virol., 88(5):2489-2507, Mar 2014. PubMed ID: 24352443. Show all entries for this paper.

Dennison2014 S. Moses Dennison, Kara M. Anasti, Frederick H. Jaeger, Shelley M. Stewart, Justin Pollara, Pinghuang Liu, Erika L. Kunz, Ruijun Zhang, Nathan Vandergrift, Sallie Permar, Guido Ferrari, Georgia D. Tomaras, Mattia Bonsignori, Nelson L. Michael, Jerome H Kim, Jaranit Kaewkungwal, Sorachai Nitayaphan, Punnee Pitisuttithum, Supachai Rerks-Ngarm, Hua-Xin Liao, Barton F. Haynes, and S. Munir Alam. Vaccine-Induced HIV-1 Envelope gp120 Constant Region 1-Specific Antibodies Expose a CD4-Inducible Epitope and Block the Interaction of HIV-1 gp140 with Galactosylceramide. J. Virol., 88(16):9406-9417, Aug 2014. PubMed ID: 24920809. Show all entries for this paper.

Derking2015 Ronald Derking, Gabriel Ozorowski, Kwinten Sliepen, Anila Yasmeen, Albert Cupo, Jonathan L. Torres, Jean-Philippe Julien, Jeong Hyun Lee, Thijs van Montfort, Steven W. de Taeye, Mark Connors, Dennis R. Burton, Ian A. Wilson, Per-Johan Klasse, Andrew B. Ward, John P. Moore, and Rogier W. Sanders. Comprehensive Antigenic Map of a Cleaved Soluble HIV-1 Envelope Trimer. PLoS Pathog, 11(3):e1004767, Mar 2015. PubMed ID: 25807248. Show all entries for this paper.

deTaeye2015 Steven W. de Taeye, Gabriel Ozorowski, Alba Torrents de la Peña, Miklos Guttman, Jean-Philippe Julien, Tom L. G. M. van den Kerkhof, Judith A. Burger, Laura K. Pritchard, Pavel Pugach, Anila Yasmeen, Jordan Crampton, Joyce Hu, Ilja Bontjer, Jonathan L. Torres, Heather Arendt, Joanne DeStefano, Wayne C. Koff, Hanneke Schuitemaker, Dirk Eggink, Ben Berkhout, Hansi Dean, Celia LaBranche, Shane Crotty, Max Crispin, David C. Montefiori, P. J. Klasse, Kelly K. Lee, John P. Moore, Ian A. Wilson, Andrew B. Ward, and Rogier W. Sanders. Immunogenicity of Stabilized HIV-1 Envelope Trimers with Reduced Exposure of Non-Neutralizing Epitopes. Cell, 163(7):1702-1715, 17 Dec 2015. PubMed ID: 26687358. Show all entries for this paper.

deTaeye2019 Steven W. de Taeye, Eden P. Go, Kwinten Sliepen, Alba Torrents de la Peña, Kimberly Badal, Max Medina-Ramírez, Wen-Hsin Lee, Heather Desaire, Ian A. Wilson, John P. Moore, Andrew B. Ward, and Rogier W. Sanders. Stabilization of the V2 Loop Improves the Presentation of V2 Loop-Associated Broadly Neutralizing Antibody Epitopes on HIV-1 Envelope Trimers. J. Biol. Chem., 294(14):5616-5631, 5 Apr 2019. PubMed ID: 30728245. Show all entries for this paper.

Diskin2013 Ron Diskin, Florian Klein, Joshua A. Horwitz, Ariel Halper-Stromberg, D. Noah Sather, Paola M. Marcovecchio, Terri Lee, Anthony P. West, Jr., Han Gao, Michael S. Seaman, Leonidas Stamatatos, Michel C. Nussenzweig, and Pamela J. Bjorkman. Restricting HIV-1 Pathways for Escape Using Rationally Designed Anti-HIV-1 Antibodies. J. Exp. Med., 210(6):1235-1249, 3 Jun 2013. PubMed ID: 23712429. Show all entries for this paper.

Doores2010 Katie J. Doores and Dennis R. Burton. Variable Loop Glycan Dependency of the Broad and Potent HIV-1-Neutralizing Antibodies PG9 and PG16. J. Virol., 84(20):10510-10521, Oct 2010. PubMed ID: 20686044. Show all entries for this paper.

Doria-Rose2012 Nicole A. Doria-Rose, Mark K. Louder, Zhongjia Yang, Sijy O'Dell, Martha Nason, Stephen D. Schmidt, Krisha McKee, Michael S. Seaman, Robert T. Bailer, and John R. Mascola. HIV-1 Neutralization Coverage Is Improved by Combining Monoclonal Antibodies That Target Independent Epitopes. J. Virol., 86(6):3393-3397, Mar 2012. PubMed ID: 22258252. Show all entries for this paper.

Doria-Rose2014 Nicole A. Doria-Rose, Chaim A. Schramm, Jason Gorman, Penny L. Moore, Jinal N. Bhiman, Brandon J. DeKosky, Michael J. Ernandes, Ivelin S. Georgiev, Helen J. Kim, Marie Pancera, Ryan P. Staupe, Han R. Altae-Tran, Robert T. Bailer, Ema T. Crooks, Albert Cupo, Aliaksandr Druz, Nigel J. Garrett, Kam H. Hoi, Rui Kong, Mark K. Louder, Nancy S. Longo, Krisha McKee, Molati Nonyane, Sijy O'Dell, Ryan S. Roark, Rebecca S. Rudicell, Stephen D. Schmidt, Daniel J. Sheward, Cinque Soto, Constantinos Kurt Wibmer, Yongping Yang, Zhenhai Zhang, NISC Comparative Sequencing Program, James C. Mullikin, James M. Binley, Rogier W. Sanders, Ian A. Wilson, John P. Moore, Andrew B. Ward, George Georgiou, Carolyn Williamson, Salim S. Abdool Karim, Lynn Morris, Peter D. Kwong, Lawrence Shapiro, and John R. Mascola. Developmental Pathway for Potent V1V2-Directed HIV-Neutralizing Antibodies. Nature, 509(7498):55-62, 1 May 2014. PubMed ID: 24590074. Show all entries for this paper.

Doria-Rose2017 Nicole A. Doria-Rose, Han R. Altae-Tran, Ryan S. Roark, Stephen D. Schmidt, Matthew S. Sutton, Mark K. Louder, Gwo-Yu Chuang, Robert T. Bailer, Valerie Cortez, Rui Kong, Krisha McKee, Sijy O'Dell, Felicia Wang, Salim S. Abdool Karim, James M. Binley, Mark Connors, Barton F. Haynes, Malcolm A. Martin, David C. Montefiori, Lynn Morris, Julie Overbaugh, Peter D. Kwong, John R. Mascola, and Ivelin S. Georgiev. Mapping Polyclonal HIV-1 Antibody Responses via Next-Generation Neutralization Fingerprinting. PLoS Pathog., 13(1):e1006148, Jan 2017. PubMed ID: 28052137. Show all entries for this paper.

Doria-RoseNA2012 Nicole A. Doria-Rose, Ivelin Georgiev, Sijy O'Dell, Gwo-Yu Chuang, Ryan P. Staupe, Jason S. McLellan, Jason Gorman, Marie Pancera, Mattia Bonsignori, Barton F. Haynes, Dennis R. Burton, Wayne C. Koff, Peter D. Kwong, and John R. Mascola. A Short Segment of the HIV-1 gp120 V1/V2 Region Is a Major Determinant of Resistance to V1/V2 Neutralizing Antibodies. J. Virol., Aug 2012. PubMed ID: 22623764. Show all entries for this paper.

Euler2011 Zelda Euler, Evelien M. Bunnik, Judith A. Burger, Brigitte D. M. Boeser-Nunnink, Marlous L. Grijsen, Jan M. Prins, and Hanneke Schuitemaker. Activity of Broadly Neutralizing Antibodies, Including PG9, PG16, and VRC01, against Recently Transmitted Subtype B HIV-1 Variants from Early and Late in the Epidemic. J. Virol., 85(14):7236-7245, Jul 2011. PubMed ID: 21561918. Show all entries for this paper.

Evans2014 Mark C. Evans, Pham Phung, Agnes C. Paquet, Anvi Parikh, Christos J. Petropoulos, Terri Wrin, and Mojgan Haddad. Predicting HIV-1 Broadly Neutralizing Antibody Epitope Networks Using Neutralization Titers and a Novel Computational Method. BMC Bioinformatics, 15:77, 19 Mar 2014. PubMed ID: 24646213. Show all entries for this paper.

Falkowska2012 Emilia Falkowska, Alejandra Ramos, Yu Feng, Tongqing Zhou, Stephanie Moquin, Laura M. Walker, Xueling Wu, Michael S. Seaman, Terri Wrin, Peter D. Kwong, Richard T. Wyatt, John R. Mascola, Pascal Poignard, and Dennis R. Burton. PGV04, an HIV-1 gp120 CD4 Binding Site Antibody, Is Broad and Potent in Neutralization but Does Not Induce Conformational Changes Characteristic of CD4. J. Virol., 86(8):4394-4403, Apr 2012. PubMed ID: 22345481. Show all entries for this paper.

Falkowska2014 Emilia Falkowska, Khoa M. Le, Alejandra Ramos, Katie J. Doores, Jeong Hyun Lee, Claudia Blattner, Alejandro Ramirez, Ronald Derking, Marit J. van Gils, Chi-Hui Liang, Ryan Mcbride, Benjamin von Bredow, Sachin S. Shivatare, Chung-Yi Wu, Po-Ying Chan-Hui, Yan Liu, Ten Feizi, Michael B. Zwick, Wayne C. Koff, Michael S. Seaman, Kristine Swiderek, John P. Moore, David Evans, James C. Paulson, Chi-Huey Wong, Andrew B. Ward, Ian A. Wilson, Rogier W. Sanders, Pascal Poignard, and Dennis R. Burton. Broadly Neutralizing HIV Antibodies Define a Glycan-Dependent Epitope on the Prefusion Conformation of gp41 on Cleaved Envelope Trimers. Immunity, 40(5):657-668, 15 May 2014. PubMed ID: 24768347. Show all entries for this paper.

Gach2013 Johannes S. Gach, Heribert Quendler, Tommy Tong, Kristin M. Narayan, Sean X. Du, Robert G. Whalen, James M. Binley, Donald N. Forthal, Pascal Poignard, and Michael B. Zwick. A Human Antibody to the CD4 Binding Site of gp120 Capable of Highly Potent but Sporadic Cross Clade Neutralization of Primary HIV-1. PLoS One, 8(8):e72054, 2013. PubMed ID: 23991039. Show all entries for this paper.

Gavrilyuk2013 Julia Gavrilyuk, Hitoshi Ban, Hisatoshi Uehara, Shannon J. Sirk, Karen Saye-Francisco, Angelica Cuevas, Elise Zablowsky, Avinash Oza, Michael S. Seaman, Dennis R. Burton, and Carlos F. Barbas, 3rd. Antibody Conjugation Approach Enhances Breadth and Potency of Neutralization of Anti-HIV-1 Antibodies and CD4-IgG. J. Virol., 87(9):4985-4993, May 2013. PubMed ID: 23427154. Show all entries for this paper.

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Gonzalez2010 Nuria Gonzalez, Amparo Alvarez, and Jose Alcami. Broadly Neutralizing Antibodies and their Significance for HIV-1 Vaccines. Curr. HIV Res., 8(8):602-612, Dec 2010. PubMed ID: 21054253. Show all entries for this paper.

Goo2012 Leslie Goo, Zahra Jalalian-Lechak, Barbra A. Richardson, and Julie Overbaugh. A Combination of Broadly Neutralizing HIV-1 Monoclonal Antibodies Targeting Distinct Epitopes Effectively Neutralizes Variants Found in Early Infection. J. Virol., 86(19):10857-10861, Oct 2012. PubMed ID: 22837204. Show all entries for this paper.

Gorman2016 Jason Gorman, Cinque Soto, Max M. Yang, Thaddeus M. Davenport, Miklos Guttman, Robert T. Bailer, Michael Chambers, Gwo-Yu Chuang, Brandon J. DeKosky, Nicole A. Doria-Rose, Aliaksandr Druz, Michael J. Ernandes, Ivelin S. Georgiev, Marissa C. Jarosinski, M. Gordon Joyce, Thomas M. Lemmin, Sherman Leung, Mark K. Louder, Jonathan R. McDaniel, Sandeep Narpala, Marie Pancera, Jonathan Stuckey, Xueling Wu, Yongping Yang, Baoshan Zhang, Tongqing Zhou, NISC Comparative Sequencing Program, James C. Mullikin, Ulrich Baxa, George Georgiou, Adrian B. McDermott, Mattia Bonsignori, Barton F. Haynes, Penny L. Moore, Lynn Morris, Kelly K. Lee, Lawrence Shapiro, John R. Mascola, and Peter D. Kwong. Structures of HIV-1 Env V1V2 with Broadly Neutralizing Antibodies Reveal Commonalities That Enable Vaccine Design. Nat. Struct. Mol. Biol., 23(1):81-90, Jan 2016. PubMed ID: 26689967. Show all entries for this paper.

Guan2013 Yongjun Guan, Marzena Pazgier, Mohammad M. Sajadi, Roberta Kamin-Lewis, Salma Al-Darmarki, Robin Flinko, Elena Lovo, Xueji Wu, James E. Robinson, Michael S. Seaman, Timothy R. Fouts, Robert C. Gallo, Anthony L. DeVico, and George K. Lewis. Diverse Specificity and Effector Function Among Human Antibodies to HIV-1 Envelope Glycoprotein Epitopes Exposed by CD4 Binding. Proc. Natl. Acad. Sci. U.S.A., 110(1):E69-E78, 2 Jan 2013. PubMed ID: 23237851. Show all entries for this paper.

Guzzo2018 Christina Guzzo, Peng Zhang, Qingbo Liu, Alice L. Kwon, Ferzan Uddin, Alexandra I. Wells, Hana Schmeisser, Raffaello Cimbro, Jinghe Huang, Nicole Doria-Rose, Stephen D. Schmidt, Michael A. Dolan, Mark Connors, John R. Mascola, and Paolo Lusso. Structural Constraints at the Trimer Apex Stabilize the HIV-1 Envelope in a Closed, Antibody-Protected Conformation. mBio, 9(6), 11 Dec 2018. PubMed ID: 30538178. Show all entries for this paper.

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Haynes2013 Barton F. Haynes and M. Juliana McElrath. Progress in HIV-1 Vaccine Development. Curr. Opin. HIV AIDS, 8(4):326-332, Jul 2013. PubMed ID: 23743722. Show all entries for this paper.

Henderson2019 Rory Henderson, Brian E. Watts, Hieu N. Ergin, Kara Anasti, Robert Parks, Shi-Mao Xia, Ashley Trama, Hua-Xin Liao, Kevin O. Saunders, Mattia Bonsignori, Kevin Wiehe, Barton F. Haynes, and S. Munir Alam. Selection of Immunoglobulin Elbow Region Mutations Impacts Interdomain Conformational Flexibility in HIV-1 Broadly Neutralizing Antibodies. Nat. Commun., 10(1):654, 8 Feb 2019. PubMed ID: 30737386. Show all entries for this paper.

Hoffenberg2013 Simon Hoffenberg, Rebecca Powell, Alexei Carpov, Denise Wagner, Aaron Wilson, Sergei Kosakovsky Pond, Ross Lindsay, Heather Arendt, Joanne DeStefano, Sanjay Phogat, Pascal Poignard, Steven P. Fling, Melissa Simek, Celia LaBranche, David Montefiori, Terri Wrin, Pham Phung, Dennis Burton, Wayne Koff, C. Richter King, Christopher L. Parks, and Michael J. Caulfield. Identification of an HIV-1 Clade A Envelope That Exhibits Broad Antigenicity and Neutralization Sensitivity and Elicits Antibodies Targeting Three Distinct Epitopes. J. Virol., 87(10):5372-5383, May 2013. PubMed ID: 23468492. Show all entries for this paper.

Hogan2018 Michael J. Hogan, Angela Conde-Motter, Andrea P. O. Jordan, Lifei Yang, Brad Cleveland, Wenjin Guo, Josephine Romano, Houping Ni, Norbert Pardi, Celia C. LaBranche, David C. Montefiori, Shiu-Lok Hu, James A. Hoxie, and Drew Weissman. Increased Surface Expression of HIV-1 Envelope Is Associated with Improved Antibody Response in Vaccinia Prime/Protein Boost Immunization. Virology, 514:106-117, 15 Jan 2018. PubMed ID: 29175625. Show all entries for this paper.

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Hraber2014 Peter Hraber, Michael S. Seaman, Robert T. Bailer, John R. Mascola, David C. Montefiori, and Bette T. Korber. Prevalence of Broadly Neutralizing Antibody Responses during Chronic HIV-1 Infection. AIDS, 28(2):163-169, 14 Jan 2014. PubMed ID: 24361678. Show all entries for this paper.

Hraber2017 Peter Hraber, Cecilia Rademeyer, Carolyn Williamson, Michael S. Seaman, Raphael Gottardo, Haili Tang, Kelli Greene, Hongmei Gao, Celia LaBranche, John R. Mascola, Lynn Morris, David C. Montefiori, and Bette Korber. Panels of HIV-1 Subtype C Env Reference Strains for Standardized Neutralization Assessments. J. Virol., 91(19), 1 Oct 2017. PubMed ID: 28747500. Show all entries for this paper.

Hraber2018 Peter Hraber, Bette Korber, Kshitij Wagh, David Montefiori, and Mario Roederer. A Single, Continuous Metric To Define Tiered Serum Neutralization Potency against Hiv. eLife, 7, 19 Jan 2018. PubMed ID: 29350181. Show all entries for this paper.

Hu2015 Joyce K. Hu, Jordan C. Crampton, Albert Cupo, Thomas Ketas, Marit J. van Gils, Kwinten Sliepen, Steven W. de Taeye, Devin Sok, Gabriel Ozorowski, Isaiah Deresa, Robyn Stanfield, Andrew B. Ward, Dennis R. Burton, Per Johan Klasse, Rogier W. Sanders, John P. Moore, and Shane Crotty. Murine Antibody Responses to Cleaved Soluble HIV-1 Envelope Trimers Are Highly Restricted in Specificity. J. Virol., 89(20):10383-10398, Oct 2015. PubMed ID: 26246566. Show all entries for this paper.

Hua2016 Casey K. Hua and Margaret E. Ackerman. Engineering Broadly Neutralizing Antibodies for HIV Prevention and Therapy. Adv. Drug Deliv. Rev., 103:157-173, 1 Aug 2016. PubMed ID: 26827912. Show all entries for this paper.

Huang2012a Jinghe Huang, Gilad Ofek, Leo Laub, Mark K. Louder, Nicole A. Doria-Rose, Nancy S. Longo, Hiromi Imamichi, Robert T. Bailer, Bimal Chakrabarti, Shailendra K. Sharma, S. Munir Alam, Tao Wang, Yongping Yang, Baoshan Zhang, Stephen A. Migueles, Richard Wyatt, Barton F. Haynes, Peter D. Kwong, John R. Mascola, and Mark Connors. Broad and Potent Neutralization of HIV-1 by a gp41-Specific Human Antibody. Nature, 491(7424):406-412, 15 Nov 2012. PubMed ID: 23151583. Show all entries for this paper.

Hutchinson2019 Jennie M. Hutchinson, Kathryn A. Mesa, David L. Alexander, Bin Yu, Sara M. O'Rourke, Kay L. Limoli, Terri Wrin, Steven G. Deeks, and Phillip W. Berman. Unusual Cysteine Content in V1 Region of gp120 from an Elite Suppressor That Produces Broadly Neutralizing Antibodies. Front. Immunol., 10:1021, 2019. PubMed ID: 31156622. Show all entries for this paper.

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Joyce2010 Joseph G. Joyce and Jan ter Meulen. Pushing the Envelope on HIV-1 Neutralization. Nat. Biotechnol., 28(9):929-931, Sep 2010. PubMed ID: 20829830. Show all entries for this paper.

Julien2013 Jean-Philippe Julien, Jeong Hyun Lee, Albert Cupo, Charles D. Murin, Ronald Derking, Simon Hoffenberg, Michael J. Caulfield, C. Richter King, Andre J. Marozsan, Per Johan Klasse, Rogier W. Sanders, John P. Moore, Ian A. Wilson, and Andrew. B Ward. Asymmetric Recognition of the HIV-1 Trimer by Broadly Neutralizing Antibody PG9. Proc. Natl. Acad. Sci. U.S.A., 110(11):4351-4356, 12 Mar 2013. PubMed ID: 23426631. Show all entries for this paper.

Julien2015 Jean-Philippe Julien, Jeong Hyun Lee, Gabriel Ozorowski, Yuanzi Hua, Alba Torrents de la Peña, Steven W. de Taeye, Travis Nieusma, Albert Cupo, Anila Yasmeen, Michael Golabek, Pavel Pugach, P. J. Klasse, John P. Moore, Rogier W. Sanders, Andrew B. Ward, and Ian A. Wilson. Design and Structure of Two HIV-1 Clade C SOSIP.664 Trimers That Increase the Arsenal of Native-Like Env Immunogens. Proc. Natl. Acad. Sci. U.S.A., 112(38):11947-11952, 22 Sep 2015. PubMed ID: 26372963. Show all entries for this paper.

Kesavardhana2017 Sannula Kesavardhana, Raksha Das, Michael Citron, Rohini Datta, Linda Ecto, Nonavinakere Seetharam Srilatha, Daniel DiStefano, Ryan Swoyer, Joseph G. Joyce, Somnath Dutta, Celia C. LaBranche, David C. Montefiori, Jessica A. Flynn, and Raghavan Varadarajan. Structure-Based Design of Cyclically Permuted HIV-1 gp120 Trimers That Elicit Neutralizing Antibodies. J. Biol. Chem., 292(1):278-291, 6 Jan 2017. PubMed ID: 27879316. Show all entries for this paper.

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Kovacs2012 James M. Kovacs, Joseph P. Nkolola, Hanqin Peng, Ann Cheung, James Perry, Caroline A. Miller, Michael S. Seaman, Dan H. Barouch, and Bing Chen. HIV-1 Envelope Trimer Elicits More Potent Neutralizing Antibody Responses than Monomeric gp120. Proc. Natl. Acad. Sci. U.S.A., 109(30):12111-12116, 24 Jul 2012. PubMed ID: 22773820. Show all entries for this paper.

Kwon2012 Young Do Kwon, Andrés Finzi, Xueling Wu, Cajetan Dogo-Isonagie, Lawrence K. Lee, Lucas R. Moore, Stephen D. Schmidt, Jonathan Stuckey, Yongping Yang, Tongqing Zhou, Jiang Zhu, David A. Vicic, Asim K. Debnath, Lawrence Shapiro, Carole A. Bewley, John R. Mascola, Joseph G. Sodroski, and Peter D. Kwong. Unliganded HIV-1 gp120 Core Structures Assume the CD4-Bound Conformation with Regulation by Quaternary Interactions and Variable Loops. Proc. Natl. Acad. Sci. U.S.A., 109(15):5663-5668, 10 Apr 2012. PubMed ID: 22451932. Show all entries for this paper.

Kwong2009 Peter D. Kwong, John R. Mascola, and Gary J. Nabel. Mining the B Cell Repertoire for Broadly Neutralizing Monoclonal Antibodies to HIV-1. Cell Host Microbe, 6(4):292-294, 22 Oct 2009. PubMed ID: 19837366. Show all entries for this paper.

Kwong2011 Peter D. Kwong, John R. Mascola, and Gary J. Nabel. Rational Design of Vaccines to Elicit Broadly Neutralizing Antibodies to HIV-1. Cold Spring Harb. Perspect. Med., 1(1):a007278, Sep 2011. PubMed ID: 22229123. Show all entries for this paper.

Kwong2012 Peter D. Kwong and John R. Mascola. Human Antibodies that Neutralize HIV-1: Identification, Structures, and B Cell Ontogenies. Immunity, 37(3):412-425, 21 Sep 2012. PubMed ID: 22999947. Show all entries for this paper.

Kwong2013 Peter D. Kwong, John R. Mascola, and Gary J. Nabel. Broadly Neutralizing Antibodies and the Search for an HIV-1 Vaccine: The End of the Beginning. Nat. Rev. Immunol., 13(9):693-701, Sep 2013. PubMed ID: 23969737. Show all entries for this paper.

Kwong2018 Peter D. Kwong and John R. Mascola. HIV-1 Vaccines Based on Antibody Identification, B Cell Ontogeny, and Epitope Structure. Immunity, 48(5):855-871, 15 May 2018. PubMed ID: 29768174. Show all entries for this paper.

Lavine2012 Christy L. Lavine, Socheata Lao, David C. Montefiori, Barton F. Haynes, Joseph G. Sodroski, Xinzhen Yang, and NIAID Center for HIV/AIDS Vaccine Immunology (CHAVI). High-Mannose Glycan-Dependent Epitopes Are Frequently Targeted in Broad Neutralizing Antibody Responses during Human Immunodeficiency Virus Type 1 Infection. J. Virol., 86(4):2153-2164, Feb 2012. PubMed ID: 22156525. Show all entries for this paper.

Leaman2010 Daniel P. Leaman, Heather Kinkead, and Michael B. Zwick. In-Solution Virus Capture Assay Helps Deconstruct Heterogeneous Antibody Recognition of Human Immunodeficiency Virus Type 1. J. Virol., 84(7):3382-3395, Apr 2010. PubMed ID: 20089658. Show all entries for this paper.

Lee2017 Jeong Hyun Lee, Raiees Andrabi, Ching-Yao Su, Anila Yasmeen, Jean-Philippe Julien, Leopold Kong, Nicholas C. Wu, Ryan McBride, Devin Sok, Matthias Pauthner, Christopher A. Cottrell, Travis Nieusma, Claudia Blattner, James C. Paulson, Per Johan Klasse, Ian A. Wilson, Dennis R. Burton, and Andrew B. Ward. A Broadly Neutralizing Antibody Targets the Dynamic HIV Envelope Trimer Apex via a Long, Rigidified, and Anionic beta-Hairpin Structure. Immunity, 46(4):690-702, 18 Apr 2017. PubMed ID: 28423342. Show all entries for this paper.

Lewis2010 George K. Lewis. Challenges of Antibody-Mediated Protection against HIV-1. Expert Rev. Vaccines, 9(7):683-687, Jul 2010. PubMed ID: 20624038. Show all entries for this paper.

Li2017 Hongru Li, Chati Zony, Ping Chen, and Benjamin K. Chen. Reduced Potency and Incomplete Neutralization of Broadly Neutralizing Antibodies against Cell-to-Cell Transmission of HIV-1 with Transmitted Founder Envs. J. Virol., 91(9), 1 May 2017. PubMed ID: 28148796. Show all entries for this paper.

Liang2016 Yu Liang, Miklos Guttman, James A. Williams, Hans Verkerke, Daniel Alvarado, Shiu-Lok Hu, and Kelly K. Lee. Changes in Structure and Antigenicity of HIV-1 Env Trimers Resulting from Removal of a Conserved CD4 Binding Site-Proximal Glycan. J. Virol., 90(20):9224-9236, 15 Oct 2016. PubMed ID: 27489265. Show all entries for this paper.

Liao2013b Hua-Xin Liao, Mattia Bonsignori, S. Munir Alam, Jason S. McLellan, Georgia D. Tomaras, M. Anthony Moody, Daniel M. Kozink, Kwan-Ki Hwang, Xi Chen, Chun-Yen Tsao, Pinghuang Liu, Xiaozhi Lu, Robert J. Parks, David C. Montefiori, Guido Ferrari, Justin Pollara, Mangala Rao, Kristina K. Peachman, Sampa Santra, Norman L. Letvin, Nicos Karasavvas, Zhi-Yong Yang, Kaifan Dai, Marie Pancera, Jason Gorman, Kevin Wiehe, Nathan I. Nicely, Supachai Rerks-Ngarm, Sorachai Nitayaphan, Jaranit Kaewkungwal, Punnee Pitisuttithum, James Tartaglia, Faruk Sinangil, Jerome H. Kim, Nelson L. Michael, Thomas B. Kepler, Peter D. Kwong, John R. Mascola, Gary J. Nabel, Abraham Pinter, Susan Zolla-Pazner, and Barton F. Haynes. Vaccine Induction of Antibodies Against a Structurally Heterogeneous Site of Immune Pressure within HIV-1 Envelope Protein Variable Regions 1 and 2. Immunity, 38(1):176-186, 24 Jan 2013. PubMed ID: 23313589. Show all entries for this paper.

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Liu2011 Lihong Liu, Michael Wen, Weiming Wang, Shumei Wang, Lifei Yang, Yong Liu, Mengran Qian, Linqi Zhang, Yiming Shao, Jason T. Kimata, and Paul Zhou. Potent and Broad Anti-HIV-1 Activity Exhibited by a Glycosyl-Phosphatidylinositol-Anchored Peptide Derived from the CDR H3 of Broadly Neutralizing Antibody PG16. J. Virol., 85(17):8467-8476, Sep 2011. PubMed ID: 21715497. Show all entries for this paper.

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Liu2015a Mengfei Liu, Guang Yang, Kevin Wiehe, Nathan I. Nicely, Nathan A. Vandergrift, Wes Rountree, Mattia Bonsignori, S. Munir Alam, Jingyun Gao, Barton F. Haynes, and Garnett Kelsoe. Polyreactivity and Autoreactivity among HIV-1 Antibodies. J. Virol., 89(1):784-798, Jan 2015. PubMed ID: 25355869. Show all entries for this paper.

Lovelace2011 Erica Lovelace, Hengyu Xu, Catherine A. Blish, Roland Strong, and Julie Overbaugh. The Role of Amino Acid Changes in the Human Immunodeficiency Virus Type 1 Transmembrane Domain in Antibody Binding and Neutralization. Virology, 421(2):235-244, 20 Dec 2011. PubMed ID: 22029936. Show all entries for this paper.

Lynch2011 John B. Lynch, Ruth Nduati, Catherine A. Blish, Barbra A. Richardson, Jennifer M. Mabuka, Zahra Jalalian-Lechak, Grace John-Stewart, and Julie Overbaugh. The Breadth and Potency of Passively Acquired Human Immunodeficiency Virus Type 1-Specific Neutralizing Antibodies Do Not Correlate with the Risk of Infant Infection. J. Virol., 85(11):5252-5261, Jun 2011. PubMed ID: 21411521. Show all entries for this paper.

Magnus2016 Carsten Magnus, Lucia Reh, and Alexandra Trkola. HIV-1 Resistance to Neutralizing Antibodies: Determination of Antibody Concentrations Leading to Escape Mutant Evolution. Virus Res., 218:57-70, 15 Jun 2016. PubMed ID: 26494166. Show all entries for this paper.

Mao2012 Youdong Mao, Liping Wang, Christopher Gu, Alon Herschhorn, Shi-Hua Xiang, Hillel Haim, Xinzhen Yang, and Joseph Sodroski. Subunit Organization of the Membrane-Bound HIV-1 Envelope Glycoprotein Trimer. Nat. Struct. Mol. Biol., 19(9):893-899, Sep 2012. PubMed ID: 22864288. Show all entries for this paper.

Mascola2010 John R. Mascola and David C. Montefiori. The Role of Antibodies in HIV Vaccines. Annu. Rev. Immunol., 28:413-444, Mar 2010. PubMed ID: 20192810. Show all entries for this paper.

McCoy2015 Laura E. McCoy, Emilia Falkowska, Katie J. Doores, Khoa Le, Devin Sok, Marit J. van Gils, Zelda Euler, Judith A. Burger, Michael S. Seaman, Rogier W. Sanders, Hanneke Schuitemaker, Pascal Poignard, Terri Wrin, and Dennis R. Burton. Incomplete Neutralization and Deviation from Sigmoidal Neutralization Curves for HIV Broadly Neutralizing Monoclonal Antibodies. PLoS Pathog., 11(8):e1005110, Aug 2015. PubMed ID: 26267277. Show all entries for this paper.

McGuire2014 Andrew T. McGuire, Jolene A. Glenn, Adriana Lippy, and Leonidas Stamatatos. Diverse Recombinant HIV-1 Envs Fail to Activate B Cells Expressing the Germline B Cell Receptors of the Broadly Neutralizing Anti-HIV-1 Antibodies PG9 and 447-52D. J. Virol., 88(5):2645-2657, Mar 2014. PubMed ID: 24352455. Show all entries for this paper.

McLellan2011 Jason S. McLellan, Marie Pancera, Chris Carrico, Jason Gorman, Jean-Philippe Julien, Reza Khayat, Robert Louder, Robert Pejchal, Mallika Sastry, Kaifan Dai, Sijy O'Dell, Nikita Patel, Syed Shahzad-ul-Hussan, Yongping Yang, Baoshan Zhang, Tongqing Zhou, Jiang Zhu, Jeffrey C. Boyington, Gwo-Yu Chuang, Devan Diwanji, Ivelin Georgiev, Young Do Kwon, Doyung Lee, Mark K. Louder, Stephanie Moquin, Stephen D. Schmidt, Zhi-Yong Yang, Mattia Bonsignori, John A. Crump, Saidi H. Kapiga, Noel E. Sam, Barton F. Haynes, Dennis R. Burton, Wayne C. Koff, Laura M. Walker, Sanjay Phogat, Richard Wyatt, Jared Orwenyo, Lai-Xi Wang, James Arthos, Carole A. Bewley, John R. Mascola, Gary J. Nabel, William R. Schief, Andrew B. Ward, Ian A. Wilson, and Peter D. Kwong. Structure of HIV-1 gp120 V1/V2 Domain with Broadly Neutralizing Antibody PG9. Nature, 480(7377):336-343, 15 Dec 2011. PubMed ID: 22113616. Show all entries for this paper.

McLinden2013 Robert J. McLinden, Celia C. LaBranche, Agnès-Laurence Chenine, Victoria R. Polonis, Michael A. Eller, Lindsay Wieczorek, Christina Ochsenbauer, John C. Kappes, Stephen Perfetto, David C. Montefiori, Nelson L. Michael, and Jerome H. Kim. Detection of HIV-1 Neutralizing Antibodies in a Human CD4+/CXCR4+/CCR5+ T-Lymphoblastoid Cell Assay System. PLoS One, 8(11):e77756, 2013. PubMed ID: 24312168. Show all entries for this paper.

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Mikell2012 Iliyana Mikell and Leonidas Stamatatos. Evolution of Cross-Neutralizing Antibody Specificities to the CD4-BS and the Carbohydrate Cloak of the HIV Env in an HIV-1-Infected Subject. PLoS One, 7(11):e49610, 2012. PubMed ID: 23152926. Show all entries for this paper.

Moore2011 Penny L. Moore, Elin S. Gray, Daniel Sheward, Maphuti Madiga, Nthabeleng Ranchobe, Zhong Lai, William J. Honnen, Molati Nonyane, Nancy Tumba, Tandile Hermanus, Sengeziwe Sibeko, Koleka Mlisana, Salim S. Abdool Karim, Carolyn Williamson, Abraham Pinter, Lynn Morris, and CAPRISA 002 Study. Potent and Broad Neutralization of HIV-1 Subtype C by Plasma Antibodies Targeting a Quaternary Epitope Including Residues in the V2 loop. J. Virol., 85(7):3128-3141, Apr 2011. PubMed ID: 21270156. Show all entries for this paper.

Moore2012 Penny L. Moore, Elin S. Gray, C. Kurt Wibmer, Jinal N. Bhiman, Molati Nonyane, Daniel J. Sheward, Tandile Hermanus, Shringkhala Bajimaya, Nancy L. Tumba, Melissa-Rose Abrahams, Bronwen E. Lambson, Nthabeleng Ranchobe, Lihua Ping, Nobubelo Ngandu, Quarraisha Abdool Karim, Salim S. Abdool Karim, Ronald I. Swanstrom, Michael S. Seaman, Carolyn Williamson, and Lynn Morris. Evolution of an HIV Glycan-Dependent Broadly Neutralizing Antibody Epitope through Immune Escape. Nat. Med., 18(11):1688-1692, Nov 2012. PubMed ID: 23086475. Show all entries for this paper.

Morales2016 Javier F. Morales, Bin Yu, Gerardo Perez, Kathryn A. Mesa, David L. Alexander, and Phillip W. Berman. Fragments of the V1/V2 Domain of HIV-1 Glycoprotein 120 Engineered for Improved Binding to the Broadly Neutralizing PG9 antibody. Mol. Immunol., 77:14-25, Sep 2016. PubMed ID: 27449907. Show all entries for this paper.

Morgand2015 Marion Morgand, Mélanie Bouvin-Pley, Jean-Christophe Plantier, Alain Moreau, Elodie Alessandri, François Simon, Craig S. Pace, Marie Pancera, David D. Ho, Pascal Poignard, Pamela J. Bjorkman, Hugo Mouquet, Michel C. Nussenzweig, Peter D. Kwong, Daniel Baty, Patrick Chames, Martine Braibant, and Francis Barin. A V1V2 Neutralizing Epitope Is Conserved in Divergent Non-M Groups of HIV-1. J. Acquir. Immune Defic. Syndr., 21 Sep 2015. PubMed ID: 26413851. Show all entries for this paper.

Mouquet2011 Hugo Mouquet, Florian Klein, Johannes F. Scheid, Malte Warncke, John Pietzsch, Thiago Y. K. Oliveira, Klara Velinzon, Michael S. Seaman, and Michel C. Nussenzweig. Memory B Cell Antibodies to HIV-1 gp140 Cloned from Individuals Infected with Clade A and B Viruses. PLoS One, 6(9):e24078, 2011. PubMed ID: 21931643. Show all entries for this paper.

Mouquet2012a Hugo Mouquet, Louise Scharf, Zelda Euler, Yan Liu, Caroline Eden, Johannes F. Scheid, Ariel Halper-Stromberg, Priyanthi N. P. Gnanapragasam, Daniel I. R. Spencer, Michael S. Seaman, Hanneke Schuitemaker, Ten Feizi, Michel C. Nussenzweig, and Pamela J. Bjorkman. Complex-Type N-Glycan Recognition by Potent Broadly Neutralizing HIV Antibodies. Proc. Natl. Acad. Sci. U.S.A, 109(47):E3268-E3277, 20 Nov 2012. PubMed ID: 23115339. Show all entries for this paper.

Nie2020 Jianhui Nie, Weijin Huang, Qiang Liu, and Youchun Wang. HIV-1 pseudoviruses constructed in China regulatory laboratory. Emerg Microbes Infect, 9(1):32-41 doi, 2020. PubMed ID: 31859609 Show all entries for this paper.

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ORourke2012 Sara M. O'Rourke, Becky Schweighardt, Pham Phung, Kathryn A. Mesa, Aaron L. Vollrath, Gwen P. Tatsuno, Briana To, Faruk Sinangil, Kay Limoli, Terri Wrin, and Phillip W. Berman. Sequences in Glycoprotein gp41, the CD4 Binding Site, and the V2 Domain Regulate Sensitivity and Resistance of HIV-1 to Broadly Neutralizing Antibodies. J. Virol., 86(22):12105-12114, Nov 2012. PubMed ID: 22933284. Show all entries for this paper.

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Pancera2013 Marie Pancera, Syed Shahzad-ul-Hussan, Nicole A. Doria-Rose, Jason S. McLellan, Robert T. Bailer, Kaifan Dai, Sandra Loesgen, Mark K. Louder, Ryan P. Staupe, Yongping Yang, Baoshan Zhang, Robert Parks, Joshua Eudailey, Krissey E. Lloyd, Julie Blinn, S. Munir Alam, Barton F. Haynes, Mohammed N. Amin, Lai-Xi Wang, Dennis R. Burton, Wayne C. Koff, Gary J. Nabel, John R. Mascola, Carole A. Bewley, and Peter D. Kwong. Structural Basis for Diverse N-Glycan Recognition by HIV-1-Neutralizing V1-V2-Directed Antibody PG16. Nat. Struct. Mol. Biol., 20(7):804-813, Jul 2013. PubMed ID: 23708607. Show all entries for this paper.

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Pegu2017 Amarendra Pegu, Ann J. Hessell, John R. Mascola, and Nancy L. Haigwood. Use of Broadly Neutralizing Antibodies for HIV-1 Prevention. Immunol. Rev., 275(1):296-312, Jan 2017. PubMed ID: 28133803. Show all entries for this paper.

Pejchal2010 Robert Pejchal, Laura M. Walker, Robyn L. Stanfield, Sanjay K. Phogat, Wayne C. Koff, Pascal Poignard, Dennis R. Burton, and Ian A. Wilson. Structure and Function of Broadly Reactive Antibody PG16 Reveal an H3 Subdomain That Mediates Potent Neutralization of HIV-1. Proc. Natl. Acad. Sci. U.S.A., 107(25):11483-11488, 22 Jun 2010. PubMed ID: 20534513. Show all entries for this paper.

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Pollara2013 Justin Pollara, Mattia Bonsignori, M. Anthony Moody, Marzena Pazgier, Barton F. Haynes, and Guido Ferrari. Epitope Specificity of Human Immunodeficiency Virus-1 Antibody Dependent Cellular Cytotoxicity (ADCC) Responses. Curr. HIV Res., 11(5):378-387, Jul 2013. PubMed ID: 24191939. Show all entries for this paper.

Prevost2018 Jérémie Prévost, Jonathan Richard, Shilei Ding, Beatriz Pacheco, Roxanne Charlebois, Beatrice H Hahn, Daniel E Kaufmann, and Andrés Finzi. Envelope Glycoproteins Sampling States 2/3 Are Susceptible to ADCC by Sera from HIV-1-Infected Individuals. Virology, 515:38-45, Feb 2018. PubMed ID: 29248757. Show all entries for this paper.

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Pugach2015 Pavel Pugach, Gabriel Ozorowski, Albert Cupo, Rajesh Ringe, Anila Yasmeen, Natalia de Val, Ronald Derking, Helen J. Kim, Jacob Korzun, Michael Golabek, Kevin de Los Reyes, Thomas J. Ketas, Jean-Philippe Julien, Dennis R. Burton, Ian A. Wilson, Rogier W. Sanders, P. J. Klasse, Andrew B. Ward, and John P. Moore. A Native-Like SOSIP.664 Trimer Based on an HIV-1 Subtype B env Gene. J. Virol., 89(6):3380-3395, Mar 2015. PubMed ID: 25589637. Show all entries for this paper.

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Ringe2011 Rajesh Ringe, Deepak Sharma, Susan Zolla-Pazner, Sanjay Phogat, Arun Risbud, Madhuri Thakar, Ramesh Paranjape, and Jayanta Bhattacharya. A Single Amino Acid Substitution in the C4 Region in gp120 Confers Enhanced Neutralization of HIV-1 by Modulating CD4 Binding Sites and V3 Loop. Virology, 418(2):123-132, 30 Sep 2011. PubMed ID: 21851958. Show all entries for this paper.

Ringe2012 Rajesh Ringe, Sanjay Phogat, and Jayanta Bhattacharya. Subtle Alteration of Residues Including N-Linked Glycans in V2 Loop Modulate HIV-1 Neutralization by PG9 and PG16 Monoclonal Antibodies. Virology, 426(1):34-41, 25 Apr 2012. PubMed ID: 22314018. Show all entries for this paper.

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Rusert2016 Peter Rusert, Roger D. Kouyos, Claus Kadelka, Hanna Ebner, Merle Schanz, Michael Huber, Dominique L. Braun, Nathanael Hozé, Alexandra Scherrer, Carsten Magnus, Jacqueline Weber, Therese Uhr, Valentina Cippa, Christian W. Thorball, Herbert Kuster, Matthias Cavassini, Enos Bernasconi, Matthias Hoffmann, Alexandra Calmy, Manuel Battegay, Andri Rauch, Sabine Yerly, Vincent Aubert, Thomas Klimkait, Jürg Böni, Jacques Fellay, Roland R. Regoes, Huldrych F. Günthard, Alexandra Trkola, and Swiss HIV Cohort Study. Determinants of HIV-1 Broadly Neutralizing Antibody Induction. Nat. Med., 22(11):1260-1267, Nov 2016. PubMed ID: 27668936. Show all entries for this paper.

Saha2012 Piyali Saha, Sanchari Bhattacharyya, Sannula Kesavardhana, Edward Roshan Miranda, P. Shaik Syed Ali, Deepak Sharma, and Raghavan Varadarajan. Designed Cyclic Permutants of HIV-1 gp120: Implications for Envelope Trimer Structure and Immunogen Design. Biochemistry, 51(9):1836-1847, 6 Mar 2012. PubMed ID: 22329717. Show all entries for this paper.

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Sanders2013 Rogier W. Sanders, Ronald Derking, Albert Cupo, Jean-Philippe Julien, Anila Yasmeen, Natalia de Val, Helen J. Kim, Claudia Blattner, Alba Torrents de la Peña, Jacob Korzun, Michael Golabek, Kevin de los Reyes, Thomas J. Ketas, Marit J. van Gils, C. Richter King, Ian A. Wilson, Andrew B. Ward, P. J. Klasse, and John P. Moore. A Next-Generation Cleaved, Soluble HIV-1 Env Trimer, BG505 SOSIP.664 gp140, Expresses Multiple Epitopes for Broadly Neutralizing but not Non-Neutralizing Antibodies. PLoS Pathog., 9(9):e1003618, Sep 2013. PubMed ID: 24068931. Show all entries for this paper.

Sather2014 D. Noah Sather, Sara Carbonetti, Delphine C. Malherbe, Franco Pissani, Andrew B. Stuart, Ann J. Hessell, Mathew D. Gray, Iliyana Mikell, Spyros A. Kalams, Nancy L. Haigwood, and Leonidas Stamatatos. Emergence of Broadly Neutralizing Antibodies and Viral Coevolution in Two Subjects during the Early Stages of Infection with Human Immunodeficiency Virus Type 1. J. Virol., 88(22):12968-12981, Nov 2014. PubMed ID: 25122781. Show all entries for this paper.

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Shang2011 Hong Shang, Xiaoxu Han, Xuanling Shi, Teng Zuo, Mark Goldin, Dan Chen, Bing Han, Wei Sun, Hao Wu, Xinquan Wang, and Linqi Zhang. Genetic and Neutralization Sensitivity of Diverse HIV-1 env Clones from Chronically Infected Patients in China. J. Biol. Chem., 286(16):14531-14541, 22 Apr 2011. PubMed ID: 21325278. Show all entries for this paper.

Shivatare2013 Sachin S. Shivatare, Shih-Huang Chang, Tsung-I Tsai, Chien-Tai Ren, Hong-Yang Chuang, Li Hsu, Chih-Wei Lin, Shiou-Ting Li, Chung-Yi Wu, and Chi-Huey Wong. Efficient Convergent Synthesis of Bi-, Tri-, and Tetra-Antennary Complex Type N-Glycans and Their HIV-1 Antigenicity. J. Am. Chem. Soc., 135(41):15382-15391, 16 Oct 2013. PubMed ID: 24032650. Show all entries for this paper.

Sliepen2015 Kwinten Sliepen, Max Medina-Ramirez, Anila Yasmeen, John P. Moore, Per Johan Klasse, and Rogier W. Sanders. Binding of Inferred Germline Precursors of Broadly Neutralizing HIV-1 Antibodies to Native-Like Envelope Trimers. Virology, 486:116-120, Dec 2015. PubMed ID: 26433050. Show all entries for this paper.

Stewart-Jones2016 Guillaume B. E. Stewart-Jones, Cinque Soto, Thomas Lemmin, Gwo-Yu Chuang, Aliaksandr Druz, Rui Kong, Paul V. Thomas, Kshitij Wagh, Tongqing Zhou, Anna-Janina Behrens, Tatsiana Bylund, Chang W. Choi, Jack R. Davison, Ivelin S. Georgiev, M. Gordon Joyce, Young Do Kwon, Marie Pancera, Justin Taft, Yongping Yang, Baoshan Zhang, Sachin S. Shivatare, Vidya S. Shivatare, Chang-Chun D. Lee, Chung-Yi Wu, Carole A. Bewley, Dennis R. Burton, Wayne C. Koff, Mark Connors, Max Crispin, Ulrich Baxa, Bette T. Korber, Chi-Huey Wong, John R. Mascola, and Peter D. Kwong. Trimeric HIV-1-Env Structures Define Glycan Shields from Clades A, B, and G. Cell, 165(4):813-826, 5 May 2016. PubMed ID: 27114034. Show all entries for this paper.

Thenin2012 Suzie Thenin, Tanawan Samleerat, Elsa Tavernier, Nicole Ngo-Giang-Huong, Gonzague Jourdain, Marc Lallemant, Francis Barin, and Martine Braibant. Envelope Glycoproteins of Human Immunodeficiency Virus Type 1 Variants Issued from Mother-Infant Pairs Display a Wide Spectrum of Biological Properties. Virology, 426(1):12-21, 25 Apr 2012. PubMed ID: 22310702. Show all entries for this paper.

Thenin2012a Suzie Thenin, Emmanuelle Roch, Tanawan Samleerat, Thierry Moreau, Antoine Chaillon, Alain Moreau, Francis Barin, and Martine Braibant. Naturally Occurring Substitutions of Conserved Residues in Human Immunodeficiency Virus Type 1 Variants of Different Clades Are Involved in PG9 and PG16 Resistance to Neutralization. J. Gen. Virol., 93(7):1495-1505, Jul 2012. PubMed ID: 22492917. Show all entries for this paper.

Tomaras2010 Georgia D. Tomaras and Barton F. Haynes. Strategies for Eliciting HIV-1 Inhibitory Antibodies. Curr. Opin. HIV AIDS, 5(5):421-427, Sep 2010. PubMed ID: 20978384. Show all entries for this paper.

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Tong2012 Tommy Tong, Ema T. Crooks, Keiko Osawa, and James M. Binley. HIV-1 Virus-Like Particles Bearing Pure Env Trimers Expose Neutralizing Epitopes but Occlude Nonneutralizing Epitopes. J. Virol., 86(7):3574-3587, Apr 2012. PubMed ID: 22301141. Show all entries for this paper.

Upadhyay2014 Chitra Upadhyay, Luzia M. Mayr, Jing Zhang, Rajnish Kumar, Miroslaw K. Gorny, Arthur Nádas, Susan Zolla-Pazner, and Catarina E. Hioe. Distinct Mechanisms Regulate Exposure of Neutralizing Epitopes in the V2 and V3 Loops of HIV-1 Envelope. J. Virol., 88(21):12853-12865, Nov 2014. PubMed ID: 25165106. Show all entries for this paper.

vandenKerkhof2016 Tom L. G. M. van den Kerkhof, Steven W. de Taeye, Brigitte D. Boeser-Nunnink, Dennis R. Burton, Neeltje A. Kootstra, Hanneke Schuitemaker, Rogier W. Sanders, and Marit J. van Gils. HIV-1 escapes from N332-directed antibody neutralization in an elite neutralizer by envelope glycoprotein elongation and introduction of unusual disulfide bonds. Retrovirology, 13(1):48, 7 Jul 2016. PubMed ID: 27388013. Show all entries for this paper.

Veillette2014 Maxime Veillette, Anik Désormeaux, Halima Medjahed, Nour-Elhouda Gharsallah, Mathieu Coutu, Joshua Baalwa, Yongjun Guan, George Lewis, Guido Ferrari, Beatrice H. Hahn, Barton F. Haynes, James E. Robinson, Daniel E. Kaufmann, Mattia Bonsignori, Joseph Sodroski, and Andres Finzi. Interaction with Cellular CD4 Exposes HIV-1 Envelope Epitopes Targeted by Antibody-Dependent Cell-Mediated Cytotoxicity. J. Virol., 88(5):2633-2644, Mar 2014. PubMed ID: 24352444. Show all entries for this paper.

vonBredow2016 Benjamin von Bredow, Juan F. Arias, Lisa N. Heyer, Brian Moldt, Khoa Le, James E. Robinson, Susan Zolla-Pazner, Dennis R. Burton, and David T. Evans. Comparison of Antibody-Dependent Cell-Mediated Cytotoxicity and Virus Neutralization by HIV-1 Env-Specific Monoclonal Antibodies. J. Virol., 90(13):6127-6139, 1 Jul 2016. PubMed ID: 27122574. Show all entries for this paper.

Voss2017 James E. Voss, Raiees Andrabi, Laura E. McCoy, Natalia de Val, Roberta P. Fuller, Terrence Messmer, Ching-Yao Su, Devin Sok, Salar N. Khan, Fernando Garces, Laura K. Pritchard, Richard T. Wyatt, Andrew B. Ward, Max Crispin, Ian A. Wilson, and Dennis R. Burton. Elicitation of Neutralizing Antibodies Targeting the V2 Apex of the HIV Envelope Trimer in a Wild-Type Animal Model. Cell Rep., 21(1):222-235, 3 Oct 2017. PubMed ID: 28978475. Show all entries for this paper.

Voss2019 James E. Voss, Alicia Gonzalez-Martin, Raiees Andrabi, Roberta P. Fuller, Ben Murrell, Laura E. McCoy, Katelyn Porter, Deli Huang, Wenjuan Li, Devin Sok, Khoa Le, Bryan Briney, Morgan Chateau, Geoffrey Rogers, Lars Hangartner, Ann J. Feeney, David Nemazee, Paula Cannon, and Dennis R. Burton. Reprogramming the Antigen Specificity of B Cells Using Genome-Editing Technologies. eLife, 8, 17 Jan 2019. PubMed ID: 30648968. Show all entries for this paper.

Wagh2016 Kshitij Wagh, Tanmoy Bhattacharya, Carolyn Williamson, Alex Robles, Madeleine Bayne, Jetta Garrity, Michael Rist, Cecilia Rademeyer, Hyejin Yoon, Alan Lapedes, Hongmei Gao, Kelli Greene, Mark K. Louder, Rui Kong, Salim Abdool Karim, Dennis R. Burton, Dan H. Barouch, Michel C. Nussenzweig, John R. Mascola, Lynn Morris, David C. Montefiori, Bette Korber, and Michael S. Seaman. Optimal Combinations of Broadly Neutralizing Antibodies for Prevention and Treatment of HIV-1 Clade C Infection. PLoS Pathog., 12(3):e1005520, Mar 2016. PubMed ID: 27028935. Show all entries for this paper.

Walker2010 Laura M. Walker, Melissa D. Simek, Frances Priddy, Johannes S. Gach, Denise Wagner, Michael B. Zwick, Sanjay K. Phogat, Pascal Poignard, and Dennis R. Burton. A Limited Number of Antibody Specificities Mediate Broad and Potent Serum Neutralization in Selected HIV-1 Infected Individuals. PLoS Pathog., 6(8), 2010. PubMed ID: 20700449. Show all entries for this paper.

Walker2010a Laura M. Walker and Dennis R. Burton. Rational Antibody-Based HIV-1 Vaccine Design: Current Approaches and Future Directions. Curr. Opin. Immunol., 22(3):358-366, Jun 2010. PubMed ID: 20299194. Show all entries for this paper.

Walker2011 Laura M. Walker, Michael Huber, Katie J. Doores, Emilia Falkowska, Robert Pejchal, Jean-Philippe Julien, Sheng-Kai Wang, Alejandra Ramos, Po-Ying Chan-Hui, Matthew Moyle, Jennifer L. Mitcham, Phillip W. Hammond, Ole A. Olsen, Pham Phung, Steven Fling, Chi-Huey Wong, Sanjay Phogat, Terri Wrin, Melissa D. Simek, Protocol G. Principal Investigators, Wayne C. Koff, Ian A. Wilson, Dennis R. Burton, and Pascal Poignard. Broad Neutralization Coverage of HIV by Multiple Highly Potent Antibodies. Nature, 477(7365):466-470, 22 Sep 2011. PubMed ID: 21849977. Show all entries for this paper.

Walker2018 Laura M. Walker and Dennis R. Burton. Passive Immunotherapy of Viral Infections: `Super-Antibodies' Enter the Fray. Nat. Rev. Immunol., 18(5):297-308, May 2018. PubMed ID: 29379211. Show all entries for this paper.

Wang2013 Wenbo Wang, Jianhui Nie, Courtney Prochnow, Carolyn Truong, Zheng Jia, Suting Wang, Xiaojiang S. Chen, and Youchun Wang. A Systematic Study of the N-Glycosylation Sites of HIV-1 Envelope Protein on Infectivity and Antibody-Mediated Neutralization. Retrovirology, 10:14, 2013. PubMed ID: 23384254. Show all entries for this paper.

Wang2018a Hongye Wang, Ting Yuan, Tingting Li, Yanpeng Li, Feng Qian, Chuanwu Zhu, Shujia Liang, Daniel Hoffmann, Ulf Dittmer, Binlian Sun, and Rongge Yang. Evaluation of Susceptibility of HIV-1 CRF01\_AE Variants to Neutralization by a Panel of Broadly Neutralizing Antibodies. Arch. Virol., 163(12):3303-3315, Dec 2018. PubMed ID: 30196320. Show all entries for this paper.

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Wen2018 Yingxia Wen, Hung V. Trinh, Christine E Linton, Chiara Tani, Nathalie Norais, DeeAnn Martinez-Guzman, Priyanka Ramesh, Yide Sun, Frank Situ, Selen Karaca-Griffin, Christopher Hamlin, Sayali Onkar, Sai Tian, Susan Hilt, Padma Malyala, Rushit Lodaya, Ning Li, Gillis Otten, Giuseppe Palladino, Kristian Friedrich, Yukti Aggarwal, Celia LaBranche, Ryan Duffy, Xiaoying Shen, Georgia D. Tomaras, David C. Montefiori, William Fulp, Raphael Gottardo, Brian Burke, Jeffrey B. Ulmer, Susan Zolla-Pazner, Hua-Xin Liao, Barton F. Haynes, Nelson L. Michael, Jerome H. Kim, Mangala Rao, Robert J. O'Connell, Andrea Carfi, and Susan W. Barnett. Generation and Characterization of a Bivalent Protein Boost for Future Clinical Trials: HIV-1 Subtypes CR01\_AE and B gp120 Antigens with a Potent Adjuvant. PLoS One, 13(4):e0194266, 2018. PubMed ID: 29698406. Show all entries for this paper.

West2012 Anthony P. West, Jr., Rachel P. Galimidi, Priyanthi N. P. Gnanapragasam, and Pamela J. Bjorkman. Single-Chain Fv-Based Anti-HIV Proteins: Potential and Limitations. J. Virol., 86(1):195-202, Jan 2012. PubMed ID: 22013046. Show all entries for this paper.

West2013 Anthony P. West, Jr., Louise Scharf, Joshua Horwitz, Florian Klein, Michel C. Nussenzweig, and Pamela J. Bjorkman. Computational Analysis of Anti-HIV-1 Antibody Neutralization Panel Data to Identify Potential Functional Epitope Residues. Proc. Natl. Acad. Sci. U.S.A., 110(26):10598-10603, 25 Jun 2013. PubMed ID: 23754383. Show all entries for this paper.

Wibmer2013 Constantinos Kurt Wibmer, Jinal N. Bhiman, Elin S Gray, Nancy Tumba, Salim S. Abdool Karim, Carolyn Williamson, Lynn Morris, and Penny L. Moore. Viral Escape from HIV-1 Neutralizing Antibodies Drives Increased Plasma Neutralization Breadth through Sequential Recognition of Multiple Epitopes and Immunotypes. PLoS Pathog, 9(10):e1003738, Oct 2013. PubMed ID: 24204277. Show all entries for this paper.

Wilen2011 Craig B. Wilen, Nicholas F. Parrish, Jennifer M. Pfaff, Julie M. Decker, Elizabeth A. Henning, Hillel Haim, Josiah E. Petersen, Jason A. Wojcechowskyj, Joseph Sodroski, Barton F. Haynes, David C. Montefiori, John C. Tilton, George M. Shaw, Beatrice H. Hahn, and Robert W. Doms. Phenotypic and Immunologic Comparison of Clade B Transmitted/Founder and Chronic HIV-1 Envelope Glycoproteins. J Virol, 85(17):8514-8527, Sep 2011. PubMed ID: 21715507. Show all entries for this paper.

Willis2016 Jordan R. Willis, Jessica A. Finn, Bryan Briney, Gopal Sapparapu, Vidisha Singh, Hannah King, Celia C. LaBranche, David C. Montefiori, Jens Meiler, and James E. Crowe, Jr. Long Antibody HCDR3s from HIV-Naive Donors Presented on a PG9 Neutralizing Antibody Background Mediate HIV Neutralization. Proc. Natl. Acad. Sci. U.S.A., 113(16):4446-4451, 19 Apr 2016. PubMed ID: 27044078. Show all entries for this paper.

Wu2011a Xueling Wu, Anita Changela, Sijy O'Dell, Stephen D. Schmidt, Marie Pancera, Yongping Yang, Baoshan Zhang, Miroslaw K. Gorny, Sanjay Phogat, James E. Robinson, Leonidas Stamatatos, Susan Zolla-Pazner, Peter D. Kwong, and John R. Mascola. Immunotypes of a Quaternary Site of HIV-1 Vulnerability and Their Recognition by Antibodies. J. Virol., 85(9):4578-4585, May 2011. PubMed ID: 21325411. Show all entries for this paper.

Wu2016 Xueling Wu and Xiang-Peng Kong. Antigenic Landscape of the HIV-1 Envelope and New Immunological Concepts Defined by HIV-1 Broadly Neutralizing Antibodies. Curr. Opin. Immunol., 42:56-64, Oct 2016. PubMed ID: 27289425. Show all entries for this paper.

Wu2018 Xilin Wu, Jia Guo, Mengyue Niu, Minghui An, Li Liu, Hui Wang, Xia Jin, Qi Zhang, Ka Shing Lam, Tongjin Wu, Hua Wang, Qian Wang, Yanhua Du, Jingjing Li, Lin Cheng, Hang Ying Tang, Hong Shang, Linqi Zhang, Paul Zhou, and Zhiwei Chen. Tandem bispecific neutralizing antibody eliminates HIV-1 infection in humanized mice. J Clin Invest, 128(6):2239-2251, Jun 1 2018. PubMed ID: 29461979. Show all entries for this paper.

Yang2014 Lili Yang and Pin Wang. Passive Immunization against HIV/AIDS by Antibody Gene Transfer. Viruses, 6(2):428-447, Feb 2014. PubMed ID: 24473340. Show all entries for this paper.

Yasmeen2014 Anila Yasmeen, Rajesh Ringe, Ronald Derking, Albert Cupo, Jean-Philippe Julien, Dennis R. Burton, Andrew B. Ward, Ian A. Wilson, Rogier W. Sanders, John P. Moore, and Per Johan Klasse. Differential Binding of Neutralizing and Non-Neutralizing Antibodies to Native-Like Soluble HIV-1 Env Trimers, Uncleaved Env Proteins, and Monomeric Subunits. Retrovirology, 11:41, 2014. PubMed ID: 24884783. Show all entries for this paper.

Yates2018 Nicole L. Yates, Allan C. deCamp, Bette T. Korber, Hua-Xin Liao, Carmela Irene, Abraham Pinter, James Peacock, Linda J. Harris, Sheetal Sawant, Peter Hraber, Xiaoying Shen, Supachai Rerks-Ngarm, Punnee Pitisuttithum, Sorachai Nitayapan, Phillip W. Berman, Merlin L. Robb, Giuseppe Pantaleo, Susan Zolla-Pazner, Barton F. Haynes, S. Munir Alam, David C. Montefiori, and Georgia D. Tomaras. HIV-1 Envelope Glycoproteins from Diverse Clades Differentiate Antibody Responses and Durability among Vaccinees. J. Virol., 92(8), 15 Apr 2018. PubMed ID: 29386288. Show all entries for this paper.

Zhang2013 Yu Zhang, Tingting Yuan, Jingjing Li, Yanyu Zhang, Jianqing Xu, Yiming Shao, Zhiwei Chen, and Mei-Yun Zhang. The Potential of the Human Immune System to Develop Broadly Neutralizing HIV-1 Antibodies: Implications for Vaccine Development. AIDS, 27(16):2529-2539, 23 Oct 2013. PubMed ID: 24100711. Show all entries for this paper.

Zhou2014 Jing Zhou, Ning Gan, Tianhua Li, Futao Hu, Xing Li, Lihong Wang, and Lei Zheng. A Cost-Effective Sandwich Electrochemiluminescence Immunosensor for Ultrasensitive Detection of HIV-1 Antibody Using Magnetic Molecularly Imprinted Polymers as Capture Probes. Biosens. Bioelectron., 54:199-206, 15 Apr 2014. PubMed ID: 24280050. Show all entries for this paper.

Zhou2017 Tongqing Zhou, Nicole A. Doria-Rose, Cheng Cheng, Guillaume B. E. Stewart-Jones, Gwo-Yu Chuang, Michael Chambers, Aliaksandr Druz, Hui Geng, Krisha McKee, Young Do Kwon, Sijy O'Dell, Mallika Sastry, Stephen D. Schmidt, Kai Xu, Lei Chen, Rita E. Chen, Mark K. Louder, Marie Pancera, Timothy G. Wanninger, Baoshan Zhang, Anqi Zheng, S. Katie Farney, Kathryn E. Foulds, Ivelin S. Georgiev, M. Gordon Joyce, Thomas Lemmin, Sandeep Narpala, Reda Rawi, Cinque Soto, John-Paul Todd, Chen-Hsiang Shen, Yaroslav Tsybovsky, Yongping Yang, Peng Zhao, Barton F. Haynes, Leonidas Stamatatos, Michael Tiemeyer, Lance Wells, Diana G. Scorpio, Lawrence Shapiro, Adrian B. McDermott, John R. Mascola, and Peter D. Kwong. Quantification of the Impact of the HIV-1-Glycan Shield on Antibody Elicitation. Cell Rep., 19(4):719-732, 25 Apr 2017. PubMed ID: 28445724. Show all entries for this paper.

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Displaying record number 2651

Download this epitope record as JSON.

MAb ID	PGT145 (PGT-145)
HXB2 Location	gp160	gp160 Epitope Map
Author Location	gp160(126-196)
Epitope
Subtype	AD
Ab Type	gp120 V2 // V2 glycan(V2g) // V2 apex
Neutralizing	P View neutralization details
Contacts and Features	View contacts and features
Species (Isotype)	human(IgG)
Patient	Donor 84
Immunogen	HIV-1 infection
Keywords	antibody binding site, antibody gene transfer, antibody generation, antibody interactions, antibody lineage, antibody polyreactivity, antibody sequence, assay or method development, autoantibody or autoimmunity, binding affinity, broad neutralizer, computational epitope prediction, elite controllers, escape, glycosylation, immunoprophylaxis, immunotherapy, neutralization, polyclonal antibodies, rate of progression, review, structure, subtype comparisons, therapeutic vaccine, vaccine antigen design, vaccine-induced immune responses, variant cross-reactivity

Notes

Showing 71 of 71 notes.

PGT145: In an effort to identify new Env immunogens able to elicit bNAbs, this study looked at Envs derived from rare individuals who possess bNAbs and are elite viral suppressors, hypothesizing that in at least some people the antibodies may mediate durable virus control. The Env proteins recovered from these individuals may more closely resemble the Envs that gave rise to bNAbs compared to the highly diverse viruses isolated from normal progressors. This study identified a treatment-naive elite suppressor, EN3, whose serum had broad neutralization. The Env sequences of EN3 had much fewer polymorphisms, compared to those of a normal progressor, EN1, who also had broad serum neutralization. This result confirmed other reports of slower virus evolution in elite suppressors. EN3 Envelope proteins were unusual in that most possessed two extra cysteines within an elongated V1 region. The impact of the extra cysteines on the binding to bNAbs, virus infectivity, and sensitivity to neutralization suggested that structural motifs in V1 can affect infectivity, and that rare viruses may be prevented from developing escape. As part of this study, the neutralization of pseudotype viruses for EN3 Env clones was assayed for several bnAbs (PG9, PG16, PGT145, PGT121, PGT128, VRC01, 4E10, and 35O22). Hutchinson2019 (elite controllers, neutralization, vaccine antigen design, polyclonal antibodies)
PGT145: Extensive structural and biochemical analyses demonstrated that PGT145 achieves recognition and neutralization by targeting quaternary structure of the cationic trimer apex required for CCR5/CSCR4 binding through long and unusually stabilized anionic β-hairpin HCDR3 loops. Analysis of generated cryoEM and X-ray Fab structures, BG505.Env.C2 alanine-scanning neutralization assays and glycan knockouts revealed that PGT145 represents a distinct class of apex bNAb that is dependent on N160, indirectly affected by N156 glycan and requires simultaneous recognition of peptide contacts from apex central residues of all 3 gp120 V1V2 loops. Logistic regression sequence analysis revealed that BG505 V2 amino acids important for neutralization included K121, R166, & T162 that directly contact PGT145; K171 that indirectly affect PGT145 via N160 & N156; and L125, I309, L175 & I326 that affect trimer stabilization via hydrophobic packing. Electrostatic pairwise interactions in HCDR3 were also required for neutralizing activity while mutations affecting other extensive electrostatic interactions reduced neutralization potency. Authors predict that PGT145 IgG binding in vivo would prevent CD4 binding through steric interference. 3BNC117-binding induced allosteric effects resulting in greater access to the apical binding site for PGT145. Lee2017 (antibody binding site, antibody interactions, structure, broad neutralizer)
PGT145: Analyses of all PDB HIV1-Env trimer (prefusion, closed) structures fulfilling certain parameters of resolution were performed to classify them on the basis of (a) antibody class which was informed by parental B cells as well as structural recognition, and (b) Env residues defining recognized HIV epitopes. Structural features of the 206 HIV epitope and bNAb paratopes were correlated with functional properties of the breadth and potency of neutralization against a 208-strain panel. bNAbs with >25% breadth of neutralization belonged to 20 classes of antibody with a large number of protruding loops and somatic hypermutation (SHM). HIV epitopes recognized placed the bNAbs into 6 categories (viz. V1V2, Glycan-V3, CD4-binding site, Silent face center, Fusion peptide and Subunit Interface). The epitopes contained high numbers of independent sequence segments and glycosylated surface area. PGT145-Env formed a distinct group within the V1V2 category, Class PGT145, as the recognition site was an Ab loop insertion into a trimeric hole at the spike apex of Env. Data for PGT145 complexed to BG505 SOSIP.664 trimer was found in PDB ID: 5V8L. Chuang2019 (antibody binding site, antibody interactions, binding affinity, antibody sequence, structure, antibody lineage, broad neutralizer)
PGT145: Soluble versions of HIV-1 Env trimers (sgp140 SOSIP.664) stabilized by a gp120-gp41 disulfide bond and a change (I559P) in gp41 have been structurally characterized. Cross-linking/mass spectrometry to evaluate the conformations of functional membrane Env and sgp140 SOSIP.664 has been reported. Differences were detected in the gp120 trimer association domain and C terminus and in the gp41 HR1 region which can guide the improvement of Env glycoprotein preparations and potentially increasing their effectiveness as a vaccine. PGT145 broadly neutralized HIV-1AD8 full-length and cytoplasmic tail-deleted Envs. Castillo-Menendez2019 (vaccine antigen design, structure)
PGT145: Lipid-based nanoparticles for the multivalent display of trimers have been shown to enhance humoral responses to trimer immunogens in the context of HIV vaccine development. After immunization with soluble MD39 SOSIP trimers (a stabilized version of BG505), trimer-conjugated liposomes improved both germinal center B cell and trimer-specific T follicular helper cell responses. In particular, MD39-liposomes showed high levels of binding by bNAbs such as V3 glycan specific PGT121, V1/V2 glycan specific PGT145, gp120/gp41 interface specific PGT151, CD4 binding site specific VRC01, and showed minimal binding by non-NAbs like CD4 binding site specific B6, and V3 specific 4025 or 39F. Tokatlian2018 (vaccine antigen design, binding affinity)
PGT145: Without SOSIP changes, cleaved Env trimers disintegrate into their gp120 and gp41-ectodomain (gp41_ECTO) components. This study demonstrates that the gp41_ECTO component is the primary source of this Env metastability and that replacing wild-type gp41_ECTO with BG505 gp41_ECTO of the uncleaved prefusion-optimized design is a general and effective strategy for trimer stabilization. A panel of 11 bNAbs, including the V2 apex recognized by PGDM1400, PGT145, and PG16, was used to assess conserved neutralizing epitopes on the trimer surface, and the main result was that the substitution was found to significantly improve trimer binding to bNAbs VRC01, PGT151, and 35O22, with P values (paired t test) of 0.0229, 0.0269, and 0.0407, respectively. He2018 (antibody interactions, glycosylation, vaccine antigen design)
PGT145: To reduce local V2 flexibility and improve the binding of V2-dependent bNAbs and germline precursor bNAbs, the authors designed BG505 SOSIP.664 trimer variants whose V1 and V2 domains were stabilized by introducing disulfide bonds either within the V2 loop or between the V1 and V2 loops. The resulting SOSIP trimer variants — E153C/K178C, E153C/K178C/G152E and I184C/E190C — have improved reactivity with V2 bNAbs and their inferred germline precursors and are more sensitive to neutralization by V2 bNAbs. The I184C/E190C mutant bound all the V2 bNAbs (PG9, PG16, PGT145, VRC26.09, and CH01) better than SOSIP.664. deTaeye2019 (antibody interactions, variant cross-reactivity, binding affinity, structure, broad neutralizer)
PGT145: This study demonstrated that bNAb signatures can be utilized to engineer HIV-1 Env vaccine immunogens eliciting Ab responses with greater neutralization breadth. Data from four large virus panels were used to comprehensively map viral signatures associated with bNAb sensitivity, hypervariable region characteristics, and clade effects. The bNAb signatures defined for the V2 epitope region were then employed to inform immunogen design in a proof-of-concept exploration of signature-based epitope targeted (SET) vaccines. V2 bNAb signature-guided mutations were introduced into Env 459C to create a trivalent vaccine which resulted in increased breadth of NAb responses compared with Env 459C alone. PGT145 was used for analyzing clade sensitivity and the V2Ab signature summaries (Table S1). Bricault2019 (antibody binding site, vaccine antigen design, computational epitope prediction, broad neutralizer)
PGT145: This review discusses the identification of super-Abs, where and how such Abs may be best applied and future directions for the field. PGT145, a prototype super-Ab, was isolated from direct functional screening of B cell clones. Antigenic region V2 apex (Table:1) Walker2018 (antibody binding site, review, structure, broad neutralizer)
PGT145: The effects of 16 glycoengineering (GE) methods on the sensitivities of 293T cell-produced pseudoviruses (PVs) to a large panel of bNAbs were investigated. Some bNAbs were dramatically impacted. PG9 and CAP256.09 were up to ˜30-fold more potent against PVs produced with co-transfected α-2,6 sialyltransferase. PGT151 and PGT121 were more potent against PVs with terminal SA removed. 35O22 and CH01 were more potent against PV produced in GNT1-cells. The effects of GE on bNAbs VRC38.01, VRC13 and PGT145 were inconsistent between Env strains, suggesting context-specific glycan clashes. Overexpressing β-galactosyltransferase during PV production 'thinned' glycan coverage, by replacing complex glycans with hybrid glycans. This impacted PV sensitivity to some bNAbs. Maximum percent neutralization by excess bnAb was also improved by GE. Remarkably, some otherwise resistant PVs were rendered sensitive by GE. Germline-reverted versions of some bnAbs usually differed from their mature counterparts, showing glycan indifference or avoidance, suggesting that glycan binding is not germline-encoded but rather, it is gained during affinity maturation. Overall, these GE tools provided new ways to improve bnAb-trimer recognition that may be useful for informing the design of vaccine immunogens to try to elicit similar bnAbs. Crooks2018 (vaccine antigen design, antibody lineage)
PGT145: A panel of bnAbs were studied to assess ongoing adaptation of the HIV-1 species to the humoral immunity of the human population. Resistance to neutralization is increasing over time, but concerns only the external glycoprotein gp120, not the MPER, suggesting a high selective pressure on gp120. Almost all the identified major neutralization epitopes of gp120 are affected by this antigenic drift, suggesting that gp120 as a whole has progressively evolved in less than 3 decades. Bouvin-Pley2014 (neutralization)
PGT145: A rare glycan hole at the V2 apex is enriched in HIV isolates neutralized by inferred precursors of prototype V2-apex bNAbs. To investigate whether this feature could focus neutralizing responses onto the apex bnAb region, rabbits were immunized with soluble trimers adapted from these Envs. Potent autologous tier 2 neutralizing responses targeting basic residues in strand C of the V2 region, which forms the core epitope for V2-apex bnAbs, were observed. Neutralizing monoclonal antibodies (mAbs) derived from these animals display features promising for subsequent broadening of the response. Four human anti-V2 bnAbs (PG9, CH01, PGT145, and CAP256.09) were used as a basis of comparison. Voss2017 (vaccine antigen design)
PGT145: This study describes the generation of CHO cell lines stably expressing the following vaccine Env Ags: CRF01_AE A244 Env gp120 protein (A244.AE) and 6240 Env gp120 protein (6240.B). The antigenic profiles of the molecules were assessed with a panel of well-characterized mAbs recognizing critical epitopes and glycosylation analysis confirming previously identified sites and revealing unknown sites at non-consensus motifs. A244.AE gp120 showed no measurable binding to PGT145 in ELISA EC50 and Surface Plasmon Resonance (SPR) assays. Wen2018 (glycosylation, vaccine antigen design)
PGT145: Assays of poly- and autoreactivity demonstrated that broadly neutralizing NAbs are significantly more poly- and autoreactive than non-neutralizing NAbs. PGT145 is neither autoreactive nor polyreactive. Liu2015a (autoantibody or autoimmunity, antibody polyreactivity)
PGT145: Panels of C clade pseudoviruses were computationally downselected from the panel of 200 C clade viruses defined by Rademeyer et al. 2016. A 12-virus panel was defined for the purpose of screening sera from vaccinees. Panels of 50 and 100 viruses were defined as smaller sets for use in testing magnitude and breadth against C clade. Published neutralization data for 16 mAbs was taken from CATNAP for the computational selections: 10-1074, 10-1074V, PGT121, PGT128, VRC26.25, VRC26.08, PGDM1400, PG9, PGT145, VRC07-523, 10E8, VRC13, 3BNC117, VRC07, VRC01, 4E10. Hraber2017 (assay or method development, neutralization)
PGT145: The immunologic effects of mutations in the Env cytoplasmic tail (CT) that included increased surface expression were explored using a vaccinia prime/protein boost protocol in mice. After vaccinia primes, CT- modified Envs induced up to 7-fold higher gp120-specific IgG, and after gp120 protein boosts, they elicited up to 16-fold greater Tier-1 HIV-1 neutralizing antibody titers. quaternary epitopes in the V1/V2 domain could not be probed using PGT145, as it doesn't bind to WT 89.6 or JRFL. Hogan2018 (vaccine antigen design)
PGT145: SOSIP.664 trimer was modified at V3 positions 306 and 308 by Leucine substitution to create hydrophobic interactions with the tryptophan residue at position 316 and the V1V2 domain. These modifications stabilized the resulting SOSIP.v5.2 S306L R308L trimers. In vivo, the induction of V3 non-NAbs was significantly reduced compared with the SOSIP.v5.2 trimers. S306L plus R308L paired substitutions had no effect on the trimer reactivity of PGT145. deTaeye2018 (broad neutralizer)
PGT145: The DS-SOSIP.4mut is a soluble, closed pre-fusion-state HIV-1 Env trimer that has improved stability and immunogenicity. It has 4 specific alterations at M154, M300, M302 and L320. PGT145 recognizes this trimer antigenically. Chuang2017 (antibody interactions)
PGT145: Three strategies were applied to perturb the structure of Env in order to make the protein more susceptible to neutralization: exposure to cold, Env-activating ligands, and a chaotropic agent. A panel of mAbs (E51, 48d, 17b, 3BNC176, 19b, 447-52D, 39F, b12, b6, PG16, PGT145, PGT126, 35O22, F240, 10E8, 7b2, 2G12) was used to test the neutralization resistance of a panel of subtype B and C pseudoviruses with and without these agents. Both cold and CD4 mimicking agents (CD4Ms) increased the sensitivity of some viruses. The chaotropic agent urea had little effect by itself, but could enhance the effects of cold or CD4Ms. Thus Env destabilizing agents can make Env more susceptible to neutralization and may hold promise as priming vaccine antigens. Johnson2017 (vaccine antigen design)
PGT145: Env from of a highly neutralization-resistant isolate, CH120.6, was shown to be very stable and conformationally-homogeneous. Its gp140 trimer retains many antigenic properties of the intact Env, while its monomeric gp120 exposes more epitopes. Thus trimer organization and stability are important determinants for occluding epitopes and conferring resistance to antibodies. Among a panel of 21 mAbs, CH120.6 was resistant to neutralization by all non-neutralizing and strain-specific mAbs, regardless of the location of their epitopes. It was weakly neutralized by several broadly-neutralizing mAbs (VRC01, NIH45-46, 12A12, PG9, PG16, PGT128, 4E10, and 10E8), and well neutralized by only 2 (PGT145 and 10-1074). Cai2017 (neutralization)
PGT145: The next generation of a computational neutralization fingerprinting (NFP) being used as a way to predict polyclonal Ab responses to HIV infection is presented. A new panel of 20 pseudoviruses, termed f61, was developed to aid in the assessment of experimental neutralization. This panel was used to assess 22 well-characterized bNAbs and mixtures thereof (HJ16, VRC01, 8ANC195, IGg1b12, PGT121, PGT128, PGT135, PG9, PGT151, 35O22, 10E8, 2F5, 4E10, VRC27, VRC-CH31, VRC-PG20, PG04, VRC23, 12A12, 3BNC117, PGT145, CH01). The new algorithms accurately predicted VRC01-like and PG9-like antibody specificities. Doria-Rose2017 (neutralization, computational epitope prediction)
PGT145: The isolation of trimers that mimic native Env by epitope-independent, biochemical methods is reported. Chromatography based approaches were used to isolate NL trimers from nonnative Env species, and the method was validated with SOSIP trimers from HIV-1 clades A and B. The resulting material was homogeneous (>95% pure), fully cleaved, and of the appropriate mol weight and size for SOSIP trimers. Since some isolated Envs, like BS208.b1 and KNH1144 T162A, did not present the glycan/quaternary structure-dependent epitope for PGT145 binding, it suggests that this method of isolation circumvents the limitations of mAb-dependdent affinity methods. Verkerke2016 (vaccine antigen design, structure)
PGT145: This study performed cyclical permutation of the V1 loop of JRFL in order to develop better gp120 trimers to elicit neutralizing antibodies. Some mutated trimers showed improved binding to several mAbs, including VRC01, VRC03, VRC-PG04, PGT128, PGT145, PGDM1400, b6, and F105. Guinea pigs immunized with prospective trimers showed improved neutralization of a panel of HIV-1 pseudoviruses. Kesavardhana2017 (vaccine antigen design, vaccine-induced immune responses)
PGT145: This study investigated the ability of native, membrane-expressed JR-FL Env trimers to elicit NAbs. Rabbits were immunized with virus-like particles (VLPs) expressing trimers (trimer VLP sera) and DNA expressing native Env trimer, followed by a protein boost (DNA trimer sera). N197 glycan- and residue 230- removal conferred sensitivity to Trimer VLP sera and DNA trimer sera respectively, showing for the first time that strain-specific holes in the "glycan fence" can allow the development of tier 2 NAbs to native spikes. All 3 sera neutralized via quaternary epitopes and exploited natural gaps in the glycan defenses of the second conserved region of JR-FL gp120. PGT145 was 1 of 2 reference PG9-like bNAbs - PG9 and PGT145. Crooks2015 (glycosylation, neutralization)
PGT145: Env residue N197 on the BG505-SOSIP trimer was mutated to test the effect of its glycosylation on the binding kinetics of CD4BS and other mAbs. Removal of the glycan had little effect on the overall structure of the molecule. Its removal resulted in increased binding of CD4 and CD4BS antibodies (VRC01, VRC03, V3-3074), but little effect on bNAbs targeting other epitopes (PG9, PG16, PGT145, 17b, A32, 2G12, PGT121, PGT126). Two CD4BS-binding antibodies tested (b12, F105) had insufficient breadth to bind the BG505-SOSIP trimer. Removal of the N197 glycan may allow for the development of better SOSIP immunogens, particularly to elicit CD4BS-specific Abs. Liang2016 (glycosylation, vaccine antigen design)
PGT145: This review classified and mapped the binding regions of 32 bNAbs isolated 2010-2016. Wu2016 (review)
PGT145: This study produced Env SOSIP trimers for clades A (strain BG505), B (strain JR-FL), and G (strain X1193). Based on simulations, the MAb-trimer structures of all MAbs tested needed to accommodate at least one glycan, including both antibodies known to require specific glycans (PG9, PGT121, PGT135, 8ANC195, 35O22) and those that bind the CD4-binding site (b12, CH103, HJ16, VRC01, VRC13). A subset of monoclonal antibodies bound to glycan arrays assayed on glass slides (VRC26.09, PGT121, 2G12, PGT128, VRC13, PGT151, 35O22), while most of the antibodies did not have affinity for oligosaccharide in the context of a glycan array (PG9, PGT145, PGDM1400, PGT135, b12, CH103, HJ16, VRC16, VRC01, VRC-PG04, VRC-CH31, VRC-PG20, 3BNC60, 12A12, VRC18b, VRC23, VRC27, 1B2530, 8ANC131, 8ANC134, 8ANC195). Stewart-Jones2016 (antibody binding site, glycosylation, structure)
PGT145: This review summarizes representative anti-HIV MAbs of the first generation (2G12, b12, 2F5, 4E10) and second generation (PG9, PG16, PGT145, VRC26.09, PGDM1400, PGT121, PGT124, PGT128, PGT135, 10-1074, VRC01, 3BNC117, CH103, PGT151, 35O22, 8ANC195, 10E8). Structures, epitopes, VDJ usage, CDR usage, and degree of somatic hypermutation are compared among these antibodies. The use of SOSIP trimers as immunogens to elicit B-cell responses is discussed. Burton2016 (review, structure)
PGT145: HIV-1 bNAb eptiope networks were predicted using 4 algorithms informed by neutralization assays using 282 Env from multiclade viruses. Patch clusters of possible Ab epitope regions were tested for significant sensitivity by site-directed mutagenesis. Epitope (Ab binding site) networks of critical Env residues for 21 bNAb (b12, PG9, PG16, PGT121, PGT122, PGT123, PGT125, PGT126, PGT127, PGT128, PGT130, PGT131, PGT135, PGT136, PGT137, PGT141, PGT142, PGT143, PGT144, PGT145 and PGV04) were delineated and found to be located mostly in variable loops of gp120, particularly in V1/V2. Evans2014 (antibody binding site, computational epitope prediction)
PGT145: Two stable homogenous gp140 Env trimer spikes, Clade A 92UG037.8 Env and Clade C C97ZA012 Env, were identified. 293T cells stably transfected with either presented fully functional surface timers, 50% of which were uncleaved. A panel of neutralizing and non-neutralizing Abs were tested for binding to the trimers. V1/V2 glycan bNAbs PGT145 bound cell surface tightly whether the trimer contained its C-terminal or not, and was competed out by sCD4. It was able to neutralize the 92UG037.8 HIV-1 isolate. Chen2015 (neutralization, binding affinity)
PGT145: Factors that independently affect bNAb induction and evolution were identified as viral load, length of untreated infection and viral diversity. Ethnically, black subjects induced bNAbs more than white subjects, but this did not correlate with type of Ab response. Fingerprint analyses of induced bNAbs showed strong subtype-dependency, with subtype B inducing significantly higher levels of CD4bs Abs and non-subtype B inducing V2-glycan specific Abs. Of the 239 bNAb antibody inducers found from 4,484 HIV-1 infected subjects,the top 105 inducers' neutralization fingerprint and epitope specificity was determined by comparison to the following antibodies - PG9, PG16, PGDM1400, PGT145 (V2 glycan); PGT121, PGT128, PGT130 (V3 glycan); VRC01, PGV04 (CD4bs) and PGT151 (interface) and 2F5, 4E10, 10E8 (MPER). Rusert2016 (neutralization, broad neutralizer)
PGT145: PGT145 was used to positively isolate a subtype B Env trimer immunogen, B41 SOSIP.664-D7324, that exists in two conformations, closed and partially open. bNAbs tested against the trimer were able to neutralize the B41 pseudovirus with a wide range of potencies. All tested non-NAbs did not neutralize B41 (IC₅₀ >50µg/ml). V1/V2 glycan bNAb, PGT145, neutralized B41 psuedovirus and bound B41 trimer strongly. Pugach2015
PGT145: The first generation of HIV trimer soluble immunogens, BG505 SOSIP.664 were tested in a mouse model for generation of nAb to neutralization-resistant circulating HIV strains. No such NAbs were induced, as mouse Abs targeted the bottom of soluble Env trimers, suggesting that the glycan shield of Env trimers is impenetrable to murine B cell receptors and that epitopes at the trimer base should be obscured in immunogen design in order to avoid non-nAb responses. Association and dissociation of known anti-trimer bNAbs (VRC01, PGT121, PGT128, PGT151, PGT135, PG9, 35O22, 3BC315 and PGT145) were found to be far greater than murine generated non-NAbs. Hu2015
PGT145: A comprehensive antigenic map of the cleaved trimer BG505 SOSIP.664 was made by bNAb cross-competition. Epitope clusters at the CD4bs, quaternary V1/V2 glycan, N332-oligomannose patch and new gp120-gp41 interface and their interactions were delineated. Epitope overlap, proximal steric inhibition, allosteric inhibition or reorientation of glycans were seen in Ab cross-competition. Thus bNAb binding to trimers can affect surfaces beyond their epitopes. PGT145, PG16 and PG9, all V1/V2 glycan trimer apex bNAbs, were strongly, reciprocally competitive with one another. V3 glycan bNAbs PGT121, PGT122, PGT123 inhibited binding of PGT145 strongly, but in a non-reciprocal manner. Unexpectedly, PGT145 strongly and non-reciprocally competed 1NC9, 8ANC195 and to a lesser extent PGT151 and 35O22, most of them gp120-gp41 binding bNAbs. Derking2015 (antibody interactions, neutralization, binding affinity, structure)
PGT145: Two clade C recombinant Env glycoprotein trimers, DU422 and ZM197M, with native-like structural and antigenic properties involving epitopes for all known classes of bNAbs, were produced and characterized. These Clade C trimers (10-15% of which are in a partially open form) were more like B41 Clade B trimers which have 50-75% trimers in the partially open configuration than like B505 Clade B trimers, almost 100% in the closed, prefusion state. The Clade C trimer ZM197M is strongly reactive to the quaternary-dependent, V1/V2 glycan trimer-apex bNAb, PGT145 but trimer DU442 and its pseudotyped virus are weakly reactive with PGT145. Julien2015 (assay or method development, structure)
PGT145: Env trimer BG505 SOSIP.664 as well as the clade B trimer B41 SOSIP.664 were stabilized using a bifunctional aldehyde (glutaraldehye, GLA) or a heterobifunctional cross-linker, EDC/NHS with modest effects on antigenicity and barely any on biochemistry or structural morphology. ELISA, DSC and SPR were used to test recognition of the trimers by bNAbs, which was preserved and by weakly NAbs or non-NAbs, which was reduced. Cross-linking partially preserves quaternary morphology so that affinity chromatography by positive selection using quaternary epitope-specific bNAabs, and negative selection using non-NAbs, enriched antigenic characteristics of the trimers. Binding of V1/V2 apex-binding bNAb PGT145 to trimers was 3.7-fold reduced by trimer cross-linking. Schiffner2016 (assay or method development, binding affinity, structure)
PGT145: HIV-1 escape from the N332-glycan dependent bNAb, PGT135, developed in an elite controller but without change to the PGT135-binding Env epitope itself. Instead an insertion increasing V1 length by up to 21 residues concomitant with an additional 1-3 glycans and 2-4 cysteines shields the epitope from PGT135. The majority of viruses tested developed a 14-fold resistance to PGT135 from month 7 to 11. In comparison, HIV-1 developed a 36 fold sensitivity to PGT145. vandenKerkhof2016 (elite controllers, neutralization, escape)
PGT145: The native-like, engineered trimer BG505 SOSIP.664 induced potent NAbs against conformational epitopes of neutralization-resistant Tier-2 viruses in rabbits and macaques, but induced cross-reactive NAbs against linear V3 epitopes of neutralization-sensitive Tier-1 viruses. A different trimer, B41 SOSIP.664 also induced strong autologous Tier-2 NAb responses in rabbits. Sera from 20 BG505 SOSIP.664-D7324 trimer-immunized rabbits were incapable of inhibiting PGT145 binding to V1/V2-glycan. 2/4 similarly trimer-immunized macaque sera however inhibited PGT145 binding by >50%. Sanders2015 (antibody generation, neutralization, binding affinity, polyclonal antibodies)
PGT145: A new trimeric immunogen, BG505 SOSIP.664 gp140, was developed that bound and activated most known neutralizing antibodies but generally did not bind antibodies lacking neuralizing activity. This highly stable immunogen mimics the Env spike of subtype A transmitted/founder (T/F) HIV-1 strain, BG505. Anti-V1/V2 glycan bNAb PGT145, neutralized BG505.T332N, the pseudoviral equivalent of the immunogen BG505 SOSIP.664 gp140, and was shown to recognize and bind the immunogen too. Sanders2013 (assay or method development, neutralization, binding affinity)
PGT145: This paper analyzed site-specific glycosylation of a soluble, recombinant trimer (BG505 SOSIP.664). This trimer mapped the extremes of simplicity and diversity of glycan processing at individual sites and revealed a mosaic of dense clusters of oligomannose glycans on the outer domain. Although individual sites usually minimally affect the global integrity of the glycan shield, they identified examples of how deleting some glycans can subtly influence neutralization by bNAbs that bind at distant sites. The network of bNAb-targeted glycans should be preserved on vaccine antigens. Neutralization profiles for V1V2 Ab, PG145, to multiple epitopes were determined. Removing the N156 or N160 or N197 glycans from either of the BG505 test viruses reduced the neutralization activities of PG145. Behrens2016 (antibody binding site, glycosylation)
PGT145: The study detailed binding kinetics of the interaction between BG505 SOSIP.664 trimer or its variants (gp120 monomer; first study of disulfide-stabilized variant gp120-gp41_ECTO protomer) and several mAbs, both neutralizing (VRC01, PGV04, PG9, PG16, PGT121, PGT122, PGT123, PGT145, PGT151, 2G12) and non-neutralizing (b6, b12, 14e, 19b, F240). V1V2 quarternary-dependent epitope-binding bNAb, PGT145, bound trimer best, did not bind protomer and BG505 gp120's monomer. Yasmeen2014 (antibody binding site, assay or method development)
PGT145: Ten mAbs were isolated from a vertically-infected infant BF520 at 15 months of age. Ab BF520.1 neutralized pseudoviruses from clades A, B and C with a breadth of 58%, putting it in the same range as second-generation bNAbs derived from adults, but its potency was lower. BF520.1 was shown to target the base of the V3 loop at the N332 supersite. V1/V2 glycan-binding, second-generation mAb, PGT145 when compared had a geometric mean of IC₅₀=0.23 µg/ml for 8/12 viruses it neutralized at a potency of 67%. The infant-derived antibodies had a lower rate of somatic hypermutation (SHM) and no indels compared to adult-derived anti-V3 mAbs. This study shows that bnAbs can develop without SHM or prolonged affinity maturation. Simonich2016 (neutralization, structure)
PGT145: This study examined the neutralization of group N, O, and P primary isolates of HIV-1 by diverse antibodies. Cross-group neutralization was observed only with the bNAbs targeting the N160 glycan-V1/V2 site. Four group O isolates, 1 group N isolate, and the group P isolates were neutralized by PG9 and/or PG16 or PGT145 at low concentrations. None of the non-M primary isolates were neutralized by bNAbs targeting other regions, except 10E8, which weakly neutralized 2 group N isolates, and 35O22 which neutralized 1 group O isolate. Bispecific bNAbs (PG9-iMab and PG16-iMab) very efficiently neutralized all non-M isolates with IC₅₀ below 1 ug/mL, except for 2 group O strains. Anti V1/V2 bNAb PGT145 was able to neutralize 1/16 tested non-M primary isolates at an IC₅₀< 1 µg/ml, RBF168,P at 0.13 µg/ml. Morgand2015 (neutralization, subtype comparisons)
PGT145: This study evaluated the binding of 15 inferred germline (gl) precursors of bNAbs that are directed to different epitope clusters, to 3 soluble native-like SOSIP.664 Env trimers - BG505, B41 and ZM197M. The trimers bound to some gl precursors, particularly those of V1V2-targeted Abs. These trimers may be useful for designing immunogens able to target gl precursors. V1/V2 apex-binding gl-PGT145 did not bind any trimers. Sliepen2015 (binding affinity, antibody lineage)
PGT145: The study's goal was to produce modified SOSIP trimers that would reduce the exposure - and, by inference, the immunogenicity - of non-NAb epitopes such as V3. The binding of several modified SOSIP trimers was compared among 12 neutralizing (PG9, PG16, PGT145, PGT121, PGT126, 2G12, PGT135, VRC01, CH103, CD4, IgG2, PGT151, 35O22) and 3 non-neutralizing antibodies (14e, 19b, b6). The V3 non-NAbs 447-52D, 39F, 14e, and 19b bound less well to all A316W variant trimers compared to wild-type trimers. Mice and rabbits immunized with modified, stabilized SOSIP trimers developed fewer V3 Ab responses than those immunized with native trimers. deTaeye2015 (antibody binding site)
PGT145: A large cross-sectional study of sera from 205 ART-naive patients infected with different HIV clades was tested against a panel of 219 cross-clade Env-pseudotyped viruses. Their neutralization was compared to the neutralization of 10 human bNAbs (10E8, 4E10, VRC01, PG9, PGT145, PGT128, 2F5, CH01, b12, 2G12) tested with a panel of 119 Env-pseudotyped viruses. Results from b12 and 2G12 suggested that these bnAbs may not be as broadly neutralizing as previously thought. PGT145 neutralized 76% of the 199 viruses tested. Hraber2014 (neutralization)
PGT145: The study compared binding and neutralization of 4 V2 apex bnAbs (PG9, CH01, PGT145, and CAP256.VRC26.09). All recognized a core epitope on V1/V2 (the N-linked glycan at N160 and cysteine-linked lysine rich, HXB2:126-196), which includes residue N160 as well as N173. The lysine rich region on strand C of HIV-1 V2 that is key for binding to the nAb contains the sequence (168)KKQK(171). Inferred germline versions of three of the prototype bnAbs were able to neutralize specific Env isolates. Soluble Env derived from one of these isolates was shown to form a well-ordered Env trimer that could serve as an immunogen to initiate a V2-apex bnAb response. Escape from bnAb PGT145 was seen in patient Donor_584 by mutations K169S, Q170K and K171I. Andrabi2015 (antibody binding site, neutralization, vaccine antigen design, escape, antibody lineage)
PGT145: Double, triple or quadruple combinations of fifteen bNAbs that target 4 distinct epitope regions: the CD4 binding site (3BNC117, VRC01, VRC07, VRC07-523, VRC13), the V3-glycan supersite (10–1074, 10-1074V, PGT121, PGT128), the V1/V2-glycan site (PG9, PGT145, PGDM1400, CAP256-VRC26.08, CAP256-VRC26.25), and the gp41 MPER epitope (10E8) were studied. Their neutralization potency and breadth were assayed against a panel of 200 acute/early subtype C strains, and compared to a novel, highly accurate predictive mathematical model (no-overlap Bliss Hill model, CombiNaber tool, LANL HIV Immunology database). These data were used to predict the best combinations of bNAbs for immunotherapy. Wagh2016 (neutralization, immunotherapy)
PGT145: Guinea pigs were immunized with either BG505 Env trimer or a complex of BG505 together with the PGT145 FAb fragment. The hypothesis was that the antibody would stabilize BG505 in its prefusion closed conformation and limit the development of antibodies against V3. Both immunogens elicited similar levels of autologous NAbs, but the BG505-PGT145 complex elicited 100-fold lower responses to V3. This finding may represent an avenue toward reducing off-target immunogenicity while generating autologous NAbs. Cheng2015 (therapeutic vaccine, vaccine antigen design)
PGT145: An atomic-level understanding of V1V2-directed bNAb recognition in a donor was used in the design of V1V2 scaffolds capable of interacting with quaternary-specific V1V2-directed bNAbs. The cocrystal structure of V1V2 with antibody CH03 from a second donor is reported and Env interactions of antibody CAP256-VRC26 from a third donor are modeled. V1V2-directed bNAbs used strand-strand interactions between a protruding Ab loop and a V1V2 strand but differed in their N-glycan recognition. Ontogeny analysis indicated that protruding loops develop early, and glycan interactions mature over time.PGT145 did not bind to the monomeric V1V2 scaffolds. The quaternary dependence might be one possible explanation for this lack of recognition. Gorman2016 (glycosylation, structure, antibody lineage)
PGT145: The sequential development of three distinct bnAb responses within a single host, CAP257, over 4.5 years of infection has been described. It showed how escape from the first wave of Abs targeting V2 exposed a second site that was the stimulus for a new wave of glycan dependent bnAbs against the CD4 binding site. These data highlighted how Ab evolution in response to viral escape mutations served to broaden the host immune response to two epitopes. A third wave of neutralization targeting an undefined epitope that did not appear to overlap with the four known sites of vulnerability on the HIV-1 envelope has been reported. These data supported the design of templates for sequential immunization strategies. Wibmer2013 (escape)
PGT145: Incomplete neutralization may decrease the ability of bnAbs to protect against HIV exposure. In order to determine the extent of non-sigmoidal slopes that plateau at <100% neutralization, a panel of 24 bnMAbs targeting different regions on Env was tested in a quantitative pseudovirus neutralization assay on a panel of 278 viral clones. All bNAbs had some viruses that they neutralized with a plateau <100%, but those targeting the V2 apex and MPER did so more often. All bnMAbs assayed had some viruses for which they had incomplete neutralization and non-sigmoidal neutralization curves. bNAbs were grouped into 3 groups based on their neutralization curves: group 1 antibodies neutralized more than 90% of susceptible viruses to >95% (PGT121-123, PGT125-128, PGT136, PGV04); group 2 was less effective, resulting in neutralization of 60-84% of susceptible viruses to >95% (b12, PGT130-131, PGT135, PGT137, PGT141-143, PGT145, 2G12, PG9); group 3 neutralized only 36-60% of susceptible viruses to >95% (PG16, PGT144, 2F5, 4E10). McCoy2015 (neutralization)
PGT145: This study investigated the immunogenicity of three ΔV1V2 deleted variants of the HIV-1 Env protein. The mutant ΔV1V2.9.VK induced a prominent response directed to epitopes effectively bound and neutralized the ΔV1V2 Env virus. This Env variant efficiently neutralized tier 1 virus SF162.This did not result in broad neutralization of neutralization-resistant virus isolates. This Env variant efficiently neutralized tier 1 virus SF162.This did not result in broad neutralization of neutralization-resistant virus isolates. BG505 SOSIP.664 trimers bind very efficiently to quaternary structure dependent, broadly neutralizing PG9 against the V1V2 domain. Bontjer2013 (vaccine antigen design, structure)
PGT145: Vectored Immuno Prophylaxis (VIP), involves passive immunization by viral vector-mediated delivery of genes encoding bnAbs for in vivo expression. Robust protection against virus infection was observed in preclinical settings when animals were given VIP to express monoclonal neutralizing Abs. This review article surveyed the status of antibody gene transfer, VIP experiments against HIV and its related virus conduced in humanized mice and macaque monkeys, and discuss the pros and cons of VIP and its opportunities and challenges towards clinical applications to control HIV/AIDS endemics. Yang2014 (immunoprophylaxis, review, antibody gene transfer)
PGT145: A gp140 trimer mosaic construct (MosM) was produced based on M group sequences. MosM bound to CD4 as well as multiple bNAbs, including VRC01, 3BNC117, PGT121, PGT126, PGT145, PG9 and PG16. The immunogenicity of this construct, both alone and mixed together with a clade C Env protein vaccine, suggest a promising approach for improving NAb responses. Nkolola2014 (vaccine antigen design)
PGT145: Computational prediction of bNAb epitopes from experimental neutralization activity data is presented. The approach relies on compressed sensing (CS) and mutual information (MI) methodologies and requires the sequences of the viral strains but does not require structural information. For PGT130, CS predicted 6 and MI predicted 3 positions, overlapping in positions 160, 166. Experimentally, PGT-145 binding was abolished by an alanine substitution at position 160, causing a >32,000 fold increase in the IC50 relative to wild type. 166 substitution resulted in 6.4 increases in IC50. Ferguson2013 (computational epitope prediction, broad neutralizer)
PGT145: Clade A Env sequence, BG505, was identified to bind to bNAbs representative of most of the known NAb classes. This sequence is the best natural sequence match (73%) to the MRCA sequence from 19 Env sequences derived from PG9 and PG16 MAbs' donor. A point mutation at position L111A of BG505 enabled more efficient production of a stable gp120 monomer, preserving the major neutralization epitopes. The antisera produced by this adjuvanted formulation of gp120 competed with bnAbs from 3 classes of non-overlapping epitopes. PGT145 showed very high neutralization titer against BG505 pseudovirus in a competitive binding assay as shown in Table 1. Hoffenberg2013 (antibody interactions, glycosylation, neutralization)
PGT145: This is a review of identified bNAbs, including the ontogeny of B cells that give rise to these antibodies. Breadth and magnitude of neutralization, unique features and similar bNAbs are listed. PGT145 is a V1/V2-directed Ab, with breadth 60%, IC₅₀ 0.31 μg per ml, and its unique feature is its discontinuous conformational epitope. Similar MAbs include PGT141 and PGT144. Kwong2013 (review)
PGT145: The conserved central region of gp120 V2 contains sulfated tyrosines (Tys173 and Tys177) that in the CD4-unbound prefusion state mediate intramolecular interaction between V2 and the conserved base of the third variable loop (V3), functionally mimicking sulfated tyrosines in CCR5 and anti-coreceptor-binding-site antibodies such as 412d. Enhancement of tyrosine sulfation decreased binding and neutralization of HIV-1 BaL by monomeric sCD4, 412d, and anti-V3 antibodies and increased recognition by the trimer-preferring antibodies PG9, PG16, CH01, and PGT145. Conversely, inhibition of tyrosine sulfation increased sensitivity to soluble CD4, 412d, and anti-V3 antibodies and diminished recognition by trimer-preferring antibodies. These results identify the sulfotyrosine-mediated V2-V3 interaction as a critical constraint that stabilizes the native HIV-1 envelope trimer and modulates its sensitivity to neutralization. Cimbro2014
PGT145: "Neutralization fingerprints" for 30 neutralizing antibodies were determined using a panel of 34 diverse HIV-1 strains. 10 antibody clusters were defined: VRC01-like, PG9-like, PGT128-like, 2F5-like, 10E8-like and separate clusters for b12, CD4, 2G12, HJ16, 8ANC195. This mAb belongs to PG9-like cluster. Georgiev2013 (neutralization)
PGT145: Although next-generation parallel sequencing techniques identify thousands of antibody somatic variants, the natural pairing between heavy and light chains is lost. This work suggests that it is possible to approximate them by comparing antibody heavy- and light-chain phylogenetic trees. Somatic variants of 10E8 from donor N152 and of antibodies PGT141-145 from donor 84 were studied. The heavy- and light-chain phylogenetic trees were remarkably similar in both cases. Zhu2013 (antibody sequence)
PGT145: This study uncovered a potentially significant contribution of V_H replacement products which are highly enriched in IgH genes for the generation of anti-HIV Abs including anti-gp41, anti-V3 loop, anti-gp120, CD4i and PGT Abs. IgH encoding PGT Abs are likely generated from multiple rounds of V_H replacements. The details of PGT145 V_H replacement products in IgH gene and mutations and amino acid sequence analysis are described in Table 1, Table 2 and Fig 4. Liao2013a (antibody sequence)
PGT145: Neutralization profiles of 7 bnAbs were analyzed against 45 Envs (A, C, D clades), obtained soon after infection (median 59 days). The transmitted variants have distinct characteristics compared to variants from chronic patients, such as shorter variable loops and fewer potential N-linked glycosylation sites (PNGS). PGT145 neutralized only 16% of these viruses. Goo2012 (neutralization, rate of progression)
PGT145: Identification of broadly neutralizing antibodies, their epitopes on the HIV-1 spike, the molecular basis for their remarkable breadth, and the B cell ontogenies of their generation and maturation are reviewed. Ontogeny and structure-based classification is presented, based on MAb binding site, type (structural mode of recognition), class (related ontogenies in separate donors) and family (clonal lineage). This MAb's classification: gp120 V1V2 site, type not yet determined, PGt145 class, PGT145 family. Kwong2012 (review, structure, broad neutralizer)
PGT145: This review discusses how analysis of infection and vaccine candidate-induced antibodies and their genes may guide vaccine design. This MAb is listed as V1/V2 conformational epitope bnAb, isolated after 2009 by neutralization screening of cultured, unselected IgG+ memory B cells. Bonsignori2012b (vaccine antigen design, vaccine-induced immune responses, review)
PGT145: PG9 and PG9-like V1V2-directed MAbs, that require an N-linked glycan at Env 160, were analyzed for gain-of-function mutations. 21 PG9-resistant HIV-1 isolates were analyzed by mutagenesis and neutralization assays. E to K mutations at positions 168, 169, 171 led to the most dramatic improvements on sensitivity to these MAbs (PG9, PG16, CH01, CH04, PGT141, PGT145). Doria-RoseNA2012 (escape)
PGT145: Glycan Asn332-targeting broadly cross-neutralizing (BCN) antibodies were studied in 2 C-clade infected women. The ASn332 glycan was absent on infecting virus, but the BCN epitope with Asn332 evolved within 6 months though immune escape from earlier antibodies. Plasma from the subject CAP177 neutralized 88% of a large multi-subtype panel of 225 heterologous viruses, whereas CAP 314 neutralized 46% of 41 heterologous viruses but failed to neutralize viruses that lack glycan at 332. PGT145 was referred to have second BCN Ab epitopes at AA 156 and 160 in addition to 332. Moore2012 (neutralization, escape)
PGT145: Vaccination efficacy of RV144 is described. The authors proposed that RV144 induced antibodies against Env V1/V2. The relationship between vaccine status and V1/V2 sequence have been characterized. The estimated cumulative HIV-1 incidence curve in the vaccine and placebo groups showed immunogenicity for K169 and 1181X genotypes and no immunogenicity for the opposite residues. PGT145 was discussed as the quaternary-structure-preferring (QSP) antibody and mutations at positions 169 and 181 were associated with significant alteration in neutralization. Rolland2012 (vaccine-induced immune responses)
PGT145: Several antibodies including 10-1074 were isolated from B-cell clone encoding PGT121, from a clade A-infected African donor using YU-2 gp140 trimers as bait. These antibodies were segregated into PGT121-like (PGT121-123 and 9 members) and 10-1074-like (20 members) groups distinguished by sequence, binding affinity, carbohydrate recognition, neutralizing activity, the V3 loop binding and the role of glycans in epitope formation. PGT145 was used as a control in virus neutralization assay. Detail information on the binding and neutralization assays are described in the figures S2-S11. Mouquet2012a (glycosylation, neutralization, binding affinity)
PGT145: MAbs PG9, PG16, CH04, PGT145 and 2909 showed anionic protruding CDR H3s, most of which were tyrosine sulphated. All also displayed β-hairpins and, although these varied substantially in orientation relative to the rest of the combining site, all appeared capable of penetrating an N-linked glycan shield to reach a cationic protein surface. McLellan2011 (structure)
PGT145: Neutralizing antibody repertoires of 4 HIV-infected donors with remarkably broad and potent neutralizing responses were probed. 17 new monoclonal antibodies that neutralize broadly across clades were rescued. These MAbs were not polyreactive. All MAbs exhibited broad cross-clade neutralizing activity, but several showed exceptional potency. PGT145 neutralized 78% of 162 isolates from major HIV clades at IC50<50 μg/ml. PGT 141–145 MAbs exhibited a strong preference for membrane-bound, trimeric HIV Env, suggesting that these MAbs broadly bound to quaternary epitopes similar to those of PG9 and PG16. This hypothesis was confirmed by competition studies, N160K sensitivity and an inability to neutralize JR-CSF pseudoviruses expressing homogenous Man9GlcNAc2 glycans. Walker2011 (antibody binding site, antibody generation, variant cross-reactivity, broad neutralizer)

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Displaying record number 2635

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MAb ID	PGT121 (PGT-121)
HXB2 Location	Env	Env Epitope Map
Author Location
Epitope	(Discontinuous epitope)
Subtype	A
Ab Type	gp120 V3 // V3 glycan (V3g)
Neutralizing	P View neutralization details
Contacts and Features	View contacts and features
Species (Isotype)	human(IgG)
Patient	Donor 17
Immunogen	HIV-1 infection
Keywords	acute/early infection, ADCC, antibody binding site, antibody gene transfer, antibody generation, antibody interactions, antibody lineage, antibody polyreactivity, antibody sequence, assay or method development, autoantibody or autoimmunity, autologous responses, binding affinity, bispecific/trispecific, broad neutralizer, chimeric antibody, computational epitope prediction, contact residues, dynamics, elite controllers, escape, glycosylation, HIV reservoir/latency/provirus, immunoprophylaxis, immunotherapy, junction or fusion peptide, kinetics, mother-to-infant transmission, mutation acquisition, neutralization, polyclonal antibodies, rate of progression, review, structure, subtype comparisons, vaccine antigen design, vaccine-induced immune responses, variant cross-reactivity, viral fitness and reversion

Notes

Showing 107 of 107 notes.

PGT121: An elite controller patient (VA40774) was identified as having an Env V1 domain that was unusually long and contained 2 additional N-glycosylation sites and 2 additional cysteine residues, relative to HXB2. When this V1 region was put into other viral backbones, the resulting virus had lower infectivity. The long V1 domain is sufficient for partial or complete escape from neutralization by V3-glycan targeting antibodies 10-1074 and PGT121, but not by another V3-glycan bNAb (PGT128) nor by other classes of bNAbs. Silver2019 (elite controllers, neutralization)
PGT121: In an effort to identify new Env immunogens able to elicit bNAbs, this study looked at Envs derived from rare individuals who possess bNAbs and are elite viral suppressors, hypothesizing that in at least some people the antibodies may mediate durable virus control. The Env proteins recovered from these individuals may more closely resemble the Envs that gave rise to bNAbs compared to the highly diverse viruses isolated from normal progressors. This study identified a treatment-naive elite suppressor, EN3, whose serum had broad neutralization. The Env sequences of EN3 had much fewer polymorphisms, compared to those of a normal progressor, EN1, who also had broad serum neutralization. This result confirmed other reports of slower virus evolution in elite suppressors. EN3 Envelope proteins were unusual in that most possessed two extra cysteines within an elongated V1 region. The impact of the extra cysteines on the binding to bNAbs, virus infectivity, and sensitivity to neutralization suggested that structural motifs in V1 can affect infectivity, and that rare viruses may be prevented from developing escape. As part of this study, the neutralization of pseudotype viruses for EN3 Env clones was assayed for several bnAbs (PG9, PG16, PGT145, PGT121, PGT128, VRC01, 4E10, and 35O22). Hutchinson2019 (elite controllers, neutralization, vaccine antigen design, polyclonal antibodies)
PGT121: This review focuses on the potential for bnAbs to induce HIV-1 remission, either alone or in combination with latency reversing agents, therapeutic vaccines, or other novel therapeutics. Ongoing human trials aimed at HIV therapy or remission are utilizing the following antibodies, alone or in combination: VRC01, VRC01-LS, VRC07-523-LS, 3BNC117, 10-1074, 10-1074-LS, PGT121, PGDM1400, 10E8.4-iMab, and SAR441236 (trispecific VRC01/PGDM1400-10E8v4). Ongoing non-human primate studies aimed to target, control, or potentially eliminate the viral reservoir are utilizing the following antibodies, alone or in combination: 3BNC117, 10-1074, N6-LS, PGT121, and the GS9721 variant of PGT121. Hsu2021 (immunotherapy, review)
PGT121: A series of mutants was produced in the CAP256-VRC26.25 heavy chain, for the purpose of avoiding the previously-identified proteolytic cleavage at position K100m. Neutralization of the mutants was tested, and the cleavage-resistant variant that showed the greatest potency was K100mA. In addition to the K100mA mutation, an LS mutation was added to the Fc portion of the heavy chain, as this change has been shown to improve the half-life of antibodies used for passive administration without affecting neutralization potency. The resulting construct was named CAP256V2LS. The pharmacokinetics of CAP256V2LS were assessed in macaques and mice, and it showed a profile similar to other antibodies used for immunotherapy. The antibody lacked autoreactivity. Structural analysis of wild-type CAP256-VRC26.25 showed that the K100m residue is not involved in interaction with the Env trimer. Neutralization data for PGT121 were used for comparison purposes. Zhang2022 (neutralization, immunotherapy, broad neutralizer)
PGT121: This study describes the design of the CAPRISA 012B human trial to assess the safety and pharmacokinetics of CAP256V2LS. Escalating dosages of CAP256V2LS, alone and in combination with 2 other mAbs (VRC07-523LS, PGT121) will be given to 52 HIV-negative and 14 HIV-positive women. Results will be reported in a future study. Mahomed2020 (immunotherapy)
PGT121: An R5 virus isolated from chronic patient NAB01 (Patient Record# 4723) was adapted in culture to growth in the presence of target cells expressing reduced levels of CD4. Entry kinetics of the virus were altered, and these alterations resulted in extended exposure of CD4-induced neutralization-sensitive epitopes to CD4. Adapted and control viruses were assayed for their neutralization by a panel of neutralizing antibodies targeting several different regions of Env (PGT121, PGT128, 1-79, 447-52d, b6, b12, VRC01, 17b, 4E10, 2F5, Z13e1). Adapted viruses showed greater sensitivity to antibodies targeting the CD4 binding site and the V3 loop. This evolution of Env resulted in increased CD4 affinity but decreased viral fitness, a phenomenon seen also in the immune-privileged CNS, particularly in macrophages. Beauparlant2017 (neutralization, viral fitness and reversion, dynamics, kinetics)
PGT121: The Chinese HIV Reference Laboratory produced 124 pseudoviruses from patients with subype B, BC, and CRF01 infections. These viruses were assigned to tiers based on their neutralization by a panel of patient sera. Their neutralization sensitivities were also measured against a panel of well-characterized mAbs (2F5, b12, 2G12, 4E10, 10E8, VRC01, VRC-CH31, CH01, PG9, PG16, PGT121, PGT126). Nie2020 (assay or method development, neutralization)
PGT121: In 8 ART-treated patients, latent viruses were induced by a viral outgrowth assay and assayed for their sensitivity to neutralization by 8 broadly neutralizing antibodies (VRC01, VRC07-523, 3BNC117, PGT121, 10-1074, PGDM1400, VRC26.25, 10E8v4-V5F-100cF). The patients' inducible reservoir of autologous viruses was generally refractory to neutralization, and higher Env diversity correlated with greater resistance to neutralization. Wilson2021 (autologous responses, neutralization, HIV reservoir/latency/provirus)
PGT121: In this clinical trial, administration of PGT121 was well tolerated in both HIV-uninfected and HIV-infected individuals. PGT121 potently and transiently inhibited HIV-1 replication in viremic individuals who had PGT121-sensitive viruses at enrollment. There were several distinct viral evolutionary patterns associated with the emergence of PGT121 resistance and viral rebound. These pathways included single point mutations, multiple point mutations, and viral recombination that led to increased resistance. Loss of D325 and the glycan at N332 were specifically associated with resistance in multiple patients. In some patients, resistance to PGT121 was accompanied by resistance to other bNAbs (10-1074, PGDM1400, or 3BNC117), as measured by neutralization assays. Stephenson2021 (mutation acquisition, neutralization, immunotherapy)
PGT121: Three vaccine regimens administered in guinea pigs over 200 weeks were compared for ability to elicit NAb polyclonal sera. While tier 1 NAb responses did increase with vaccination, tier 2 NAb heterologous responses did not. The 3 regimens were C97 (monovalent, Clade C gp140), 4C (tetravalent, 4 Clade C mosaic gp140s), ABCM (tetravalent, Clades A, B, C and mosaic gp140s). Polyclonal sera generated from the 4C regimen, compared to the C97 regimen, was markedly superior at outcompeting PGT121 binding to gp140 antigens, suggesting that the 4C regimen induced the most robust V3-specific antibodies. Bricault2018 (antibody generation, vaccine-induced immune responses, polyclonal antibodies)
PGT121: Novel Env pseudoviruses were derived from 22 patients in China infected with subtype CRF01_AE viruses. Neutralization IC50 was determined for 11 bNAbs: VRC01, NIH45-46G54W, 3BNC117, PG9, PG16, 2G12, PGT121, 10-1074, 2F5, 4E10, and 10E8. The CRF01_AE pseudoviruses exhibited different susceptibility to these bNAbs. Overall, 4E10, 10E8, and 3BNC117 neutralized all 22 env-pseudotyped viruses, followed by NIH45-46G54W and VRC01, which neutralized more than 90% of the viruses. 2F5, PG9, and PG16 showed only moderate breadth, while the other three bNAbs neutralized none of these pseudoviruses. Specifically, 10E8, NIH45-46G54Wand 3BNC117 showed the highest efficiency, combining neutralization potency and breadth. Mutations at position 160, 169, 171 were associated with resistance to PG9 and PG16, while loss of a potential glycan at position 332 conferred insensitivity to V3-glycan-targeting bNAbs. These results may help in choosing bNAbs that can be used preferentially for prophylactic or therapeutic approaches in China. Wang2018a (assay or method development, neutralization, subtype comparisons)
PGT121: A novel CD4bs bNAb, 1-18, is identified with breadth (97% against a 119-strain multiclade panel) and potency exceeding (IC₅₀ = 0.048 µg/mL) most V_H1-46 and V_H1-2 class bNAbs like 3BNC117, VRC01, N6, 8ANC131, 10-1074, PGT151, PGT121, 8ANC195, PG16 and PGDM1400. 1-18 effectively restricts viral escape better than bNAbs 3BNC117 and VRC01. While 1-18 targets the CD4bs like VRC01-like Abs, it recognizes the epitope differently. Neutralizing activity against VRC01 Ab-class escapes is maintained by 1-18. In humanized mice infected by strain 1_YU2, viral suppression is also maintained by 1-18. V_H1-46-derived B cell clone 4.1 from patient IDC561 produced potent, broadly active Abs. Subclone 4.1 is characterized by a 6 aa CDRH1 insertion lengthening it from 8 to 14 aa. and produces bNAbs 1-18 and 1-55. Cryo-EM at 2.5A of 1-18 in complex with BG505_SOSIP.664 suggests their insertion increases inter-protomer contacts by a negatively charged DDDPYTDDD motif, resulting in an enlargement of the buried surface on HIV-1 gp120. Variations in glycosylation is thought to confer higher neutralizing activity on 1-18 over 1-55. Schommers2020 (antibody binding site, antibody generation, antibody interactions, neutralization, escape, binding affinity, antibody sequence, structure, broad neutralizer, contact residues)
PGT121: Soluble versions of HIV-1 Env trimers (sgp140 SOSIP.664) stabilized by a gp120-gp41 disulfide bond and a change (I559P) in gp41 have been structurally characterized. Cross-linking/mass spectrometry to evaluate the conformations of functional membrane Env and sgp140 SOSIP.664 has been reported. Differences were detected in the gp120 trimer association domain and C terminus and in the gp41 HR1 region which can guide the improvement of Env glycoprotein preparations and potentially increasing their effectiveness as a vaccine. PGT121 broadly neutralized HIV-1AD8 full-length and cytoplasmic tail-deleted Envs. Castillo-Menendez2019 (vaccine antigen design, structure)
PGT121: The latent viral reservoir is the critical barrier for the development of an HIV-1 cure. This study showed that the V3 glycan-dependent bNAb PGT121 together with the TLR7 agonist vesatolimod (GS-9620) administered during ART suppression delayed viral rebound following ART discontinuation in SHIV-SF162P3-infected rhesus monkeys that initiated ART during early acute infection. Moreover, the subset of PGT121+GS-9620 treated monkeys that did not show viral rebound following ART discontinuation also did not reveal virus by highly sensitive adoptive transfer and CD8 depletion studies. These data demonstrate the potential of bNAb administration together with innate immune stimulation as a possible strategy to target the viral reservoir. Borducchi2018 (antibody interactions, immunotherapy, HIV reservoir/latency/provirus)
PGT121: Chemoenzymatic synthesis, antigenicity, and immunogenicity of the V3 N334 glycopeptides from HIV-1 A244 gp120 have been reported. A synthetic V3 glycopeptide carrying a N334 high-mannose glycan was recognized by bNAb PGT128 and PGT126 but not by 10-1074. Rabbit immunization with the synthetic three-component A244 glycopeptide immunogen elicited substantial glycan-dependent antibodies with broad reactivity to various HIV-1 gp120/gp140 carrying N332 or N334 glycosylation sites. PGT121 was unable to bind to the A244 glycopeptides bearing a high-mannose N-glycan but could bind to the glycopeptide with a sialylated complex- type N-glycan placed at the N301 site (Fig: S1). Cai2018 (glycosylation, vaccine antigen design, structure)
PGT121: Lipid-based nanoparticles for the multivalent display of trimers have been shown to enhance humoral responses to trimer immunogens in the context of HIV vaccine development. After immunization with soluble MD39 SOSIP trimers (a stabilized version of BG505), trimer-conjugated liposomes improved both germinal center B cell and trimer-specific T follicular helper cell responses. In particular, MD39-liposomes showed high levels of binding by bNAbs such as V3 glycan specific PGT121, V1/V2 glycan specific PGT145, gp120/gp41 interface specific PGT151, CD4 binding site specific VRC01, and showed minimal binding by non-NAbs like CD4 binding site specific B6, and V3 specific 4025 or 39F. Tokatlian2018 (vaccine antigen design, binding affinity)
PGT121: Without SOSIP changes, cleaved Env trimers disintegrate into their gp120 and gp41-ectodomain (gp41_ECTO) components. This study demonstrates that the gp41_ECTO component is the primary source of this Env metastability and that replacing wild-type gp41_ECTO with BG505 gp41_ECTO of the uncleaved prefusion-optimized design is a general and effective strategy for trimer stabilization. A panel of 11 bNAbs, including the N332 supersite recognized by PGT121, PGT128, PGT135, and 2G12, was used to assess conserved neutralizing epitopes on the trimer surface, and the main result was that the substitution was found to significantly improve trimer binding to bNAbs VRC01, PGT151, and 35O22, with P values (paired t test) of 0.0229, 0.0269, and 0.0407, respectively. He2018 (antibody interactions, glycosylation, vaccine antigen design)
PGT121: To reduce local V2 flexibility and improve the binding of V2-dependent bNAbs and germline precursor bNAbs, the authors designed BG505 SOSIP.664 trimer variants whose V1 and V2 domains were stabilized by introducing disulfide bonds either within the V2 loop or between the V1 and V2 loops. The resulting SOSIP trimer variants — E153C/K178C, E153C/K178C/G152E and I184C/E190C — have improved reactivity with V2 bNAbs and their inferred germline precursors and are more sensitive to neutralization by V2 bNAbs. PGT121, PG9, PG16, and CH01 bound better to the E153C/R178C/G152E mutant than to SOSIP.664. The I184C/E190C mutant bound all the V2 bNAbs (PG9, PG16, PGT145, VRC26.09, and CH01) better than SOSIP.664. deTaeye2019 (antibody interactions, variant cross-reactivity, binding affinity, structure, broad neutralizer)
PGT121: This study demonstrated that bNAb signatures can be utilized to engineer HIV-1 Env vaccine immunogens eliciting Ab responses with greater neutralization breadth. Data from four large virus panels were used to comprehensively map viral signatures associated with bNAb sensitivity, hypervariable region characteristics, and clade effects. The bNAb signatures defined for the V2 epitope region were then employed to inform immunogen design in a proof-of-concept exploration of signature-based epitope targeted (SET) vaccines. V2 bNAb signature-guided mutations were introduced into Env 459C to create a trivalent vaccine which resulted in increased breadth of NAb responses compared with Env 459C alone. PGT121 was used for machine learning regression prediction and to analyze statistical details (Table S4). Bricault2019 (antibody binding site, vaccine antigen design, computational epitope prediction, broad neutralizer)
PGT121: The authors describe single-component molecules they designed that incorporate two (bispecific) or three (trispecific) bNAbs that recognize HIV Env exclusively, a bispecific CrossmAb targeting two epitopes on the major HIV coreceptor, CCR5, and bi- and trispecifics that cross-target both Env and CCR5. These newly designed molecules displayed exceptional breadth, neutralizing 98 to 100% of a 109-virus panel, as well as additivity and potency compared to those of the individual parental control IgGs. They constructed 8 different versions of tri-specific 10E8Fab-PGT121fv-PGDM1400fv, 3 different versions of tri-specific 10E8Fab-PGT121fv-PGDM1400fv.V8, and a tri-specific PRO-140Fab-PGDM1400fv-PGT121fv. A trispecific containing 10E8-PGT121-PGDM1400 Env-specific binding sites was equally potent (median IC₅₀ of 0.0135 µg/ml), while a trispecific molecule targeting Env and CCR5 simultaneously, (10E8Fab-PGDM1400fv-PRO 140fv) demonstrated even greater potency, with a median IC₅₀ of 0.007 µg/ml. Other trispecifics, using RoAb13Fab in combination with a bi-specific PGT121fv-PRO 140fv, neutralized most of the viruses in the smaller global panel but were not exceptionally potent. Khan2018 (neutralization, bispecific/trispecific)
PGT121: In vitro neutralization data against 25 subtype A, 100 C, and 20 D pseudoviruses of 8 bNAbs (3BNC117, N6, VRC01, VRC07-523LS, CAP256-VRC26.25, PGDM1400, 10–1074, PGT121) and 2 bispecific Abs under clinical development (10E8-iMAb, 3BNC117-PGT135) was studied to assess the antibodies’ potential to prevent infection by dominant HIV-1 subtypes in sub-Saharan Africa. In vivo protection of these Abs and their 2-Ab combination was predicted using a function of in vitro neutralization based on data from a macaque simian-human immunodeficiency virus (SHIV) challenge study. Conclusions were that 1. bNAb combinations outperform individual bNAbs 2. Different bNAb combinations were optimal against different HIV subtypes 3. Bispecific 10E8-iMAb outperformed all combinations and 4. 10E8-iMAb in combination with other conventional Abs was predicted to be the best combination against HIV-infection. Wagh2018 (immunotherapy)
PGT121: Adenovirus serotype 5 (Ad5) and adeno-associated virus serotype 1 (AAV1) vectors were used to deliver bNAb PGT121 in WT and immunocompromised C57BL/6 mice and in HIV-1-infected bone marrow-liver-thymus (BLT) humanized mice. Ad5.PGT121 and AAV1.PGT121 produced functional Ab in vivo. Ad5.PGT121 produced PGT121 rapidly within 6 h, whereas AAV1.PGT121 produced detectable PGT121 in serum by 72 h. Serum PGT121 levels were rapidly reduced by the generation of anti-PGT121 antibodies in immunocompetent mice but were durably maintained in immunocompromised mice. In HIV-1-infected BLT humanized mice, Ad5.PGT121 resulted in a greater reduction of viral loads than did AAV1.PGT121. Ad5.PGT121 also led to more-sustained virologic control than purified PGT121 IgG. Ad5.PGT121 afforded more rapid, robust, and durable antiviral efficacy than AAV1.PGT121 and purified PGT121 IgG in HIV-1-infected humanized mice. Badamchi-Zadeh2018 (immunotherapy)
PGT121: This review summarizes current advances in antibody lineage-based design and epitope-based vaccine design. Antibody lineage-based design is described for VRC01, PGT121 and PG9 antibody classes, and epitope-based vaccine design is described for the CD4-binding site, as well as fusion peptide and glycan-V3 cites of vulnerability. Kwong2018 (antibody binding site, vaccine antigen design, vaccine-induced immune responses, review, antibody lineage, broad neutralizer, junction or fusion peptide)
PGT121: This review discusses how the identification of super-antibodies, where and how such antibodies may be best applied and future directions for the field. PGT121, a prototype super-Ab, was isolated from human B cell clones and is in Phase I clinical development. Antigenic region V3 glycan (Table:1). Walker2018 (antibody binding site, review, broad neutralizer)
PGT121: Polyreactive properties of natural and artificially engineered HIV-1 bNAbs were studied, with almost 60% of the tested HIV-1 bNAbs (including this one) exhibiting low to high polyreactivity in different immunoassays. A previously unappreciated polyreactive binding for PGT121, PGT128, NIH45-46W, m2, and m7 was reported. Binding affinity, thermodynamic, and molecular dynamics analyses revealed that the co-emergence of enhanced neutralizing capacities and polyreactivity was due to an intrinsic conformational flexibility of the antigen-binding sites of bNAbs, allowing a better accommodation of divergent HIV-1 Env variants. Prigent2018 (antibody polyreactivity)
PGT121: A systems glycobiology approach was applied to reverse engineer the relationship between bNAb binding and glycan effects on Env proteins. Glycan occupancy was interrogated across every potential N-glycan site in 94 recombinant gp120 antigens. Using a Bayesian machine learning algorithm, bNAb-specific glycan footprints were identified and used to design antigens that selectively alter bNAb antigenicity. The novel synthesized antigens uccessfully bound to target bNAbs with enhanced and selective antigenicity. Yu2018 (glycosylation, vaccine antigen design)
PGT121: The effects of 16 glycoengineering (GE) methods on the sensitivities of 293T cell-produced pseudoviruses (PVs) to a large panel of bNAbs were investigated. Some bNAbs were dramatically impacted. PG9 and CAP256.09 were up to ˜30-fold more potent against PVs produced with co-transfected α-2,6 sialyltransferase. PGT151 and PGT121 were more potent against PVs with terminal SA removed. 35O22 and CH01 were more potent against PV produced in GNT1-cells. The effects of GE on bNAbs VRC38.01, VRC13 and PGT145 were inconsistent between Env strains, suggesting context-specific glycan clashes. Overexpressing β-galactosyltransferase during PV production 'thinned' glycan coverage, by replacing complex glycans with hybrid glycans. This impacted PV sensitivity to some bNAbs. Maximum percent neutralization by excess bnAb was also improved by GE. Remarkably, some otherwise resistant PVs were rendered sensitive by GE. Germline-reverted versions of some bnAbs usually differed from their mature counterparts, showing glycan indifference or avoidance, suggesting that glycan binding is not germline-encoded but rather, it is gained during affinity maturation. Overall, these GE tools provided new ways to improve bnAb-trimer recognition that may be useful for informing the design of vaccine immunogens to try to elicit similar bnAbs. Crooks2018 (vaccine antigen design, antibody lineage)
PGT121: This review discusses current HIV bNAb immunogen design strategies, recent progress made in the development of animal models to evaluate potential vaccine candidates, advances in the technology to analyze antibody responses, and emerging concepts in understanding B cell developmental pathways that may facilitate HIV vaccine design strategies. Andrabi2018 (vaccine antigen design, review)
PGT121: A panel of bnAbs were studied to assess ongoing adaptation of the HIV-1 species to the humoral immunity of the human population. Resistance to neutralization is increasing over time, but concerns only the external glycoprotein gp120, not the MPER, suggesting a high selective pressure on gp120. Almost all the identified major neutralization epitopes of gp120 are affected by this antigenic drift, suggesting that gp120 as a whole has progressively evolved in less than 3 decades. Bouvin-Pley2014 (neutralization)
PGT121: Bispecific bNAbs containing anti-CD4bs VRC01 and anti-V3 glycan PGT121 were constructed by linking the single chain (Sc) bNAbs with flexible (G₄S)_n linkers at IgG F_c and were found to have greater neutralization breadth than parental bNAbs when optimal. The optimal bis-specific NAb, dVRC01-5X-PGT121, was one that crosslinked protomers within one Env spike. Combination of this bispecific with a third bNAb, anti-MPER 10E8, gave 99.5%, i.e. nearly pan-neutralization of a 208 virus panel with a geometric mean IC₅₀ below 0.1 µg/ml. Steinhardt2018 (neutralization, immunotherapy, bispecific/trispecific)
PGT121: The first cryo-EM structure of a cross-linked vaccine antigen was solved. The 4.2 Å structure of HIV-1 BG505 SOSIP soluble recombinant Env in complex with a bNAb PGV04 Fab fragment revealed how cross-linking affects key properties of the trimer. SOSIP and GLA-SOSIP trimers were compared for antigenicity by ELISA, using a large panel of mAbs previously determined to react with BG505 Env. Non-NAbs globally lost reactivity (7-fold median loss of binding), likely because of covalent stabilization of the cross-linked ‘closed’ form of the GLA-SOSIP trimer that binds non-NAbs weakly or not at all. V3-specific non-NAbs showed 2.1–3.3-fold reduced binding. Three autologous rabbit monoclonal NAbs to the N241/N289 ‘glycan-hole’ surface, showed a median ˜1.5-fold reduction in binding. V3 non-NAb 4025 showed residual binding to the GLA-SOSIP trimer. By contrast, bNAbs like PGT121 broadly retained reactivity significantly better than non-NAbs, with exception of PGT145 (3.3-5.3 fold loss of binding in ELISA and SPR). Schiffner2018 (vaccine antigen design, binding affinity, structure)
PGT121: Assays of poly- and autoreactivity demonstrated that broadly neutralizing NAbs are significantly more poly- and autoreactive than non-neutralizing NAbs. PGT121 is neither autoreactive nor polyreactive. Liu2015a (autoantibody or autoimmunity, antibody polyreactivity)
PGT121: Panels of C clade pseudoviruses were computationally downselected from the panel of 200 C clade viruses defined by Rademeyer et al. 2016. A 12-virus panel was defined for the purpose of screening sera from vaccinees. Panels of 50 and 100 viruses were defined as smaller sets for use in testing magnitude and breadth against C clade. Published neutralization data for 16 mAbs was taken from CATNAP for the computational selections: 10-1074, 10-1074V, PGT121, PGT128, VRC26.25, VRC26.08, PGDM1400, PG9, PGT145, VRC07-523, 10E8, VRC13, 3BNC117, VRC07, VRC01, 4E10. Hraber2017 (assay or method development, neutralization)
PGT121: A panel of 14 pseudoviruses of subtype CRF01_AE was developed to assess the neutralization of several neutralizing antibodies (b12, PG9, PG16, 4E10, 10E8, 2F5, PGT121, PGT126, 2G12). Neutralization was assessed in both TZM-bl and A3R5 cell-based assays. Most viruses were more susceptible to mAb-neutralization in A3R5 than in the TZM-bl cell-based assay. The increased neutralization sensitivity observed in the A3R5 assay was not linked to the year of virus transmission or to the stages of infection, but chronic viruses from the years 1990-92 were more sensitive to neutralization than the more current viruses, in both assays. Chenine2018 (assay or method development, neutralization, subtype comparisons)
PGT121: Nanodiscs (discoidal lipid bilayer particles of 10-17 nm surrounded by membrane scaffold protein) were used to incorporate Env complexes for the purpose of vaccine platform generation. The Env-NDs (Env-NDs) were characterized for antigenicity and stability by non-NAbs and NAbs. Most NAb epitopes in gp41 MPER and in the gp120:gp41 interface were well exposed while non-NAb cell surface epitopes were generally masked. Anti-V3 variable NAb PGT121, binds at a fraction of the binding of 2G12 to Env-ND, and this binding is sensitive to glutaraldehyde treatment . Witt2017 (vaccine antigen design, binding affinity)
PGT121: This study showed evidence of escape of circulating HIV-1 clade C in an individual from autologous BCN antibodies by three distinct mechanisms, 1) due to a N332S mutation (2) by increasing V1 loop length and (3) incorporation of protective N-glycan residues in V1 loop. Pseudotyped viruses expressing autologous Envs were found to be resistant to autologous BCN plasma, PGT121 and PGT128 despite the majority of Envs containing an intact N332 residue. Resistance of the Envs to neutralization was found to be correlated with a N332S mutation and acquisition of protective N-glycans. Deshpande2016 (autologous responses, glycosylation, escape)
PGT121: The DS-SOSIP.4mut is a soluble, closed pre-fusion-state HIV-1 Env trimer that has improved stability and immunogenicity. It has 4 specific alterations at M154, M300, M302 and L320. PGT121 recognizes this trimer antigenically. Chuang2017 (antibody interactions)
PGT121: A panel of mAbs (2G12, VRC01, HJ16, 2F5, 4E10, 35O22, PG9, PGT121, PGT126, 10-1074) was tested to compare their efficacy in cell-free versus cell-cell transmission. Almost all bNAbs (with the exception of anti-CD4 mAb Leu3a) blocked cell-free infection with greater potency than cell-cell infection, and showed greater potency in neutralization of cell-free viruses. The lower effectiveness on neutralization was particularly pronounced for transmitted/founder viruses, and less pronounced for chronic and lab-adapted viruses. The study highlights that the ability of an antibody to inhibit cell-cell transmission may be an important consideration in the development of Abs for prophylaxis. Li2017 (immunoprophylaxis, neutralization)
PGT121: The next generation of a computational neutralization fingerprinting (NFP) being used as a way to predict polyclonal Ab responses to HIV infection is presented. A new panel of 20 pseudoviruses, termed f61, was developed to aid in the assessment of experimental neutralization. This panel was used to assess 22 well-characterized bNAbs and mixtures thereof (HJ16, VRC01, 8ANC195, IGg1b12, PGT121, PGT128, PGT135, PG9, PGT151, 35O22, 10E8, 2F5, 4E10, VRC27, VRC-CH31, VRC-PG20, PG04, VRC23, 12A12, 3BNC117, PGT145, CH01). The new algorithms accurately predicted VRC01-like and PG9-like antibody specificities. Doria-Rose2017 (neutralization, computational epitope prediction)
PGT121: This review focuses on the potential role of HIV-1-specific NAbs in preventing HIV-1 infection. Several NAbs have provided protection from infection in SHIV challenge studies in primates: b12, VRC01, VRC07-523LS, 3BNC117, PG9, PGT121, PGT126, 10-1074, 2G12, 4E10, 2F5, 10E8. Pegu2017 (immunoprophylaxis, review)
PGT121: Crystal structures of the HIV-1 Env trimer with fully processed and native glycosylation are presented, complexed with the V3-loop bNAb 10-1074 and IOMA, a new CD4bs bNAb. There were fine specificity differences between bNAb 10-1074 and PGT121-family members. PGT122 was two-fold more potent against strains including the N156 PNGS, whereas 10-1074 was four-fold more potent against strains lacking the N156 PNGS. Gristick2016 (glycosylation)
PGT121: In 33 individuals (14 uninfected and 19 HIV-1-infected), intravenous infusion of 10-1074 was well tolerated. In infected individuals with sensitive strains, 10-1074 decreased viremia, but escape variants and viral rebound occurred within a few weeks. Escape variants were also resistant to V3 antibody PGT121, but remained sensitive to antibodies targeting other epitopes (3BNC117, VRC01 or PGDM1400). Loss of the PNGS at position N332 or 324G(D/N)IR327 mutation was associated with resistance to 10-1074 and PGT121. Caskey2017 (escape, immunotherapy)
PGT121: To understand HIV neutralization mediated by the MPER, antibodies and viruses were studied from CAP206, a patient known to produce MPER-targeted neutralizing mAbs. 41 human mAbs were isolated from CAP206 at various timepoints after infection, and 4 macaque mAbs were isolated from animals immunized with CAP206 Env proteins. Two rare, naturally-occuring single-residue changes in Env were identified in transmitted/founder viruses (W680G in CAP206 T/F and Y681D in CH505 T/F) that made the viruses less resistant to neutralization. The results point to the role of the MPER in mediating the closed trimer state, and hence the neutralization resistance of HIV. CH58 was one of several mAbs tested for neutralization of transmitted founder viruses isolated from clade C infected individuals CAP206 and CH505, compared to T/F viruses containing MPER mutations that confer enhanced neutralization sensitivity. Bradley2016a (neutralization)
PGT121: The study compared the binding characteristics of V3-glycan antibodies, specifically PGT121, PGT128, PGT135, PCDN38A, and 3 newly-derived lineages of mAbs from Donor N170. The gene usage for PGT121 is given as: IGHV 4-59*01, IGHJ 6*03, IGLV L3-21*02, IGLJ L3*02. Longo2016 (antibody binding site, antibody sequence)
PGT121: This study investigated the ability of native, membrane-expressed JR-FL Env trimers to elicit NAbs. Rabbits were immunized with virus-like particles (VLPs) expressing trimers (trimer VLP sera) and DNA expressing native Env trimer, followed by a protein boost (DNA trimer sera). N197 glycan- and residue 230- removal conferred sensitivity to Trimer VLP sera and DNA trimer sera respectively, showing for the first time that strain-specific holes in the "glycan fence" can allow the development of tier 2 NAbs to native spikes. All 3 sera neutralized via quaternary epitopes and exploited natural gaps in the glycan defenses of the second conserved region of JR-FL gp120. PGT121 was 1 of 2 reference PGT128-like bNAbs - PGT121 and PGT128. Crooks2015 (glycosylation, neutralization)
PGT121: New antibodies were isolated from 3 patients: Donor 14 (PDGM11, PGDM12, PGDM13, PGDM14), Donor 82 (PGDM21), and Donor 26 (PGDM31). These bnAbs bound both the GDIR peptide (Env 324-327) and the high-mannose patch glycans, enabling broad reactivity. N332 glycan was absolutely required for neutralization, while N301 glycan modestly affected neutralization. Removing N156 and N301 glycans together while retaining N332 glycan abrogated neutralization for PGDM12 and PGDM21. Neutralization by PGDM11-14 bnAbs depended on R327A and H330A substitutions and neutralization by PGDM21 depended on D325A and H330A substitutions. G324A mutation resulted in slight loss of neutralization for both antibody families. In comparison, 2G12 and PGT135 did not show any dependence on residues in the 324GDIR327 region for neutralization activity, although PGT135 did show dependence on H330. Sok2016 (antibody binding site, glycosylation)
PGT121: Env residue N197 on the BG505-SOSIP trimer was mutated to test the effect of its glycosylation on the binding kinetics of CD4BS and other mAbs. Removal of the glycan had little effect on the overall structure of the molecule. Its removal resulted in increased binding of CD4 and CD4BS antibodies (VRC01, VRC03, V3-3074), but little effect on bNAbs targeting other epitopes (PG9, PG16, PGT145, 17b, A32, 2G12, PGT121, PGT126). Two CD4BS-binding antibodies tested (b12, F105) had insufficient breadth to bind the BG505-SOSIP trimer. Removal of the N197 glycan may allow for the development of better SOSIP immunogens, particularly to elicit CD4BS-specific Abs. Liang2016 (glycosylation, vaccine antigen design)
PGT121: This review classified and mapped the binding regions of 32 bNAbs isolated 2010-2016. Wu2016 (review)
PGT121: This study produced Env SOSIP trimers for clades A (strain BG505), B (strain JR-FL), and G (strain X1193). Based on simulations, the MAb-trimer structures of all MAbs tested needed to accommodate at least one glycan, including both antibodies known to require specific glycans (PG9, PGT121, PGT135, 8ANC195, 35O22) and those that bind the CD4-binding site (b12, CH103, HJ16, VRC01, VRC13). A subset of monoclonal antibodies bound to glycan arrays assayed on glass slides (VRC26.09, PGT121, 2G12, PGT128, VRC13, PGT151, 35O22), while most of the antibodies did not have affinity for oligosaccharide in the context of a glycan array (PG9, PGT145, PGDM1400, PGT135, b12, CH103, HJ16, VRC16, VRC01, VRC-PG04, VRC-CH31, VRC-PG20, 3BNC60, 12A12, VRC18b, VRC23, VRC27, 1B2530, 8ANC131, 8ANC134, 8ANC195). Stewart-Jones2016 (antibody binding site, glycosylation, structure)
PGT121: This study assessed the ADCC activity of antibodies of varied binding types, including CD4bs (b6, b12, VRC01, PGV04, 3BNC117), V2 (PG9, PG16), V3 (PGT126, PGT121, 10-1074), oligomannose (2G12), MPER (2F5, 4E10, 10E8), CD4i (17b, X5), C1/C5 (A32, C11), cluster I (240D, F240), and cluster II (98-6, 126-7). ADCC activity was correlated with binding to Env on the surfaces of virus-infected cells. ADCC was correlated with neutralization, but not always for lab-adapted viruses such as HIV-1 NLA-3. vonBredow2016 (ADCC)
PGT121: This review summarizes representative anti-HIV MAbs of the first generation (2G12, b12, 2F5, 4E10) and second generation (PG9, PG16, PGT145, VRC26.09, PGDM1400, PGT121, PGT124, PGT128, PGT135, 10-1074, VRC01, 3BNC117, CH103, PGT151, 35O22, 8ANC195, 10E8). Structures, epitopes, VDJ usage, CDR usage, and degree of somatic hypermutation are compared among these antibodies. The use of SOSIP trimers as immunogens to elicit B-cell responses is discussed. Burton2016 (review, structure)
PGT121: bNAbs were found to have potent activating but not inhibitory FcγR-mediated effector function that can confer protection by blocking viral entry or suppressing viremia. bNAb activity is augmented with engineered Fc domains when assessed in in vivo models of HIV-1 entry or in therapeutic models using HIV-1-infected humanized mice. Enhanced FcγR engagement is not restricted by epitope specificity or neutralization potency as chimeras composed of human anti-V3 PGT121 Fab and mouse Fc had improved or reduced in vivo activity depending on the Fc used. Bournazos2014 (neutralization, chimeric antibody)
PGT121: HIV-1 bNAb eptiope networks were predicted using 4 algorithms informed by neutralization assays using 282 Env from multiclade viruses. Patch clusters of possible Ab epitope regions were tested for significant sensitivity by site-directed mutagenesis. Epitope (Ab binding site) networks of critical Env residues for 21 bNAb (b12, PG9, PG16, PGT121, PGT122, PGT123, PGT125, PGT126, PGT127, PGT128, PGT130, PGT131, PGT135, PGT136, PGT137, PGT141, PGT142, PGT143, PGT144, PGT145 and PGV04) were delineated and found to be located mostly in variable loops of gp120, particularly in V1/V2. Evans2014 (antibody binding site, computational epitope prediction)
PGT121: Factors that independently affect bNAb induction and evolution were identified as viral load, length of untreated infection and viral diversity. Ethnically, black subjects induced bNAbs more than white subjects, but this did not correlate with type of Ab response. Fingerprint analyses of induced bNAbs showed strong subtype-dependency, with subtype B inducing significantly higher levels of CD4bs Abs and non-subtype B inducing V2-glycan specific Abs. Of the 239 bNAb antibody inducers found from 4,484 HIV-1 infected subjects,the top 105 inducers' neutralization fingerprint and epitope specificity was determined by comparison to the following antibodies - PG9, PG16, PGDM1400, PGT145 (V2 glycan); PGT121, PGT128, PGT130 (V3 glycan); VRC01, PGV04 (CD4bs) and PGT151 (interface) and 2F5, 4E10, 10E8 (MPER). Rusert2016 (neutralization, broad neutralizer)
PGT121: PGT145 was used to positively isolate a subtype B Env trimer immunogen, B41 SOSIP.664-D7324, that exists in two conformations, closed and partially open. bNAbs tested against the trimer were able to neutralize the B41 pseudovirus with a wide range of potencies. All tested non-NAbs did not neutralize B41 (IC₅₀ >50µg/ml). V3 glycan bNAb, PGT121, neutralized the B41 pseudovirus and bound B41 trimer well. Pugach2015
PGT121: The first generation of HIV trimer soluble immunogens, BG505 SOSIP.664 were tested in a mouse model for generation of nAb to neutralization-resistant circulating HIV strains. No such NAbs were induced, as mouse Abs targeted the bottom of soluble Env trimers, suggesting that the glycan shield of Env trimers is impenetrable to murine B cell receptors and that epitopes at the trimer base should be obscured in immunogen design in order to avoid non-nAb responses. Association and dissociation of known anti-trimer bNAbs (VRC01, PGT121, PGT128, PGT151, PGT135, PG9, 35O22, 3BC315 and PGT145) were found to be far greater than murine generated non-NAbs. Hu2015
PGT121: A comprehensive antigenic map of the cleaved trimer BG505 SOSIP.664 was made by bNAb cross-competition. Epitope clusters at the CD4bs, quaternary V1/V2 glycan, N332-oligomannose patch and new gp120-gp41 interface and their interactions were delineated. Epitope overlap, proximal steric inhibition, allosteric inhibition or reorientation of glycans were seen in Ab cross-competition. Thus bNAb binding to trimers can affect surfaces beyond their epitopes. PGT121, PGT122, PGT123, PGT125, PGT126 and PGT128, all N332-V3 glycan oligomannose patch-binding bNAbs, were strongly, reciprocally competitive with one another. They inhibited binding of PGT145 strongly, but in a non-reciprocal manner. Non-reciprocal enhancement of PGT121 binding to trimer was seen in the presence of NIH45-46. Derking2015 (antibody interactions, neutralization, binding affinity, structure)
PGT121: Two clade C recombinant Env glycoprotein trimers, DU422 and ZM197M, with native-like structural and antigenic properties involving epitopes for all known classes of bNAbs, were produced and characterized. These Clade C trimers (10-15% of which are in a partially open form) were more like B41 Clade B trimers which have 50-75% trimers in the partially open configuration than like B505 Clade B trimers, almost 100% in the closed, prefusion state. Both the Clade C trimers as well as their pseudotyped viruses reacted strongly with and were neutralized by V3-glycan-binding PGT121. Julien2015 (assay or method development, structure)
PGT121: Env trimer BG505 SOSIP.664 as well as the clade B trimer B41 SOSIP.664 were stabilized using a bifunctional aldehyde (glutaraldehye, GLA) or a heterobifunctional cross-linker, EDC/NHS with modest effects on antigenicity and barely any on biochemistry or structural morphology. ELISA, DSC and SPR were used to test recognition of the trimers by bNAbs, which was preserved and by weakly NAbs or non-NAbs, which was reduced. Cross-linking partially preserves quaternary morphology so that affinity chromatography by positive selection using quaternary epitope-specific bNAabs, and negative selection using non-NAbs, enriched antigenic characteristics of the trimers. Binding of the anti-N332-glycan supersite bNAb PGT121 to trimers was minimally affected by trimer cross-linking. Schiffner2016 (assay or method development, binding affinity, structure)
PGT121: The native-like, engineered trimer BG505 SOSIP.664 induced potent NAbs against conformational epitopes of neutralization-resistant Tier-2 viruses in rabbits and macaques, but induced cross-reactive NAbs against linear V3 epitopes of neutralization-sensitive Tier-1 viruses. A different trimer, B41 SOSIP.664 also induced strong autologous Tier-2 NAb responses in rabbits. Sera from 2/20 BG505 SOSIP.664-D7324 trimer-immunized rabbits were capable of inhibiting PGT121 binding to V3-glycan. 1/4 similarly trimer-immunized macaque sera also inhibited PGT121 binding by >50%. Sanders2015 (antibody generation, neutralization, binding affinity, polyclonal antibodies)
PGT121: A new trimeric immunogen, BG505 SOSIP.664 gp140, was developed that bound and activated most known neutralizing antibodies but generally did not bind antibodies lacking neuralizing activity. This highly stable immunogen mimics the Env spike of subtype A transmitted/founder (T/F) HIV-1 strain, BG505. Anti-V3 glycan bNAb PGT121, neutralized BG505.T332N, the pseudoviral equivalent of the immunogen BG505 SOSIP.664 gp140, and was shown to recognize and bind the immunogen too. Sanders2013 (assay or method development, neutralization, binding affinity)
PGT121: This review discusses the application of bNAbs for HIV treatment and eradication, focusing on bnAbs that target key epitopes, specifically: 2G12, 2F5, 4E10, VRC01, 3BNC117, PGT121, VRC26.08, VRC26.09, PGDM1400, and 10-1074. PGT121 is distinct from other V3-specific mAbs because it forms a binding site with two functional surfaces. It has been administered in therapeutic trials in primates. Stephenson2016 (immunotherapy, review)
PGT121: This review discusses an array of methods to engineer more effective bNAbs for immunotherapy. Antibody PGT121 is an example of engineering through rational mutations; it has been combined with 10-1074 as part of a strategy to combine the CDRs of bnAbs targeting similar epitopes. Hua2016 (immunotherapy, review)
PGT121: This paper analyzed site-specific glycosylation of a soluble, recombinant trimer (BG505 SOSIP.664). This trimer mapped the extremes of simplicity and diversity of glycan processing at individual sites and revealed a mosaic of dense clusters of oligomannose glycans on the outer domain. Although individual sites usually minimally affect the global integrity of the glycan shield, they identified examples of how deleting some glycans can subtly influence neutralization by bNAbs that bind at distant sites. The network of bNAb-targeted glycans should be preserved on vaccine antigens. Neutralization profiles for mannose-patch binding Ab, PGT121, to multiple epitopes were determined. Deleting the N137 glycan made BG505.T332N more vulnerable to PGT121, but the corresponding change has no meaningful effect on oligomannose content in the SOSIP.664 trimer context. Behrens2016 (antibody binding site, glycosylation)
PGT121: A mathematical model was developed to predict the Ab concentration at which antibody escape variants outcompete their ancestors, and this concentration was termed the mutant selection window (MSW). The MSW was determined experimentally for 12 pairings of diverse HIV strains against 7 bnAbs (b12, 2G12, PG9, PG16, PGT121, PGT128, 2F5). The neutralization of PGT121 was assayed against BG505 (resistant strain) and BG505-T332N (sensitive strain). Magnus2016 (neutralization, escape)
PGT121: Ten mAbs were isolated from a vertically-infected infant BF520 at 15 months of age. Ab BF520.1 neutralized pseudoviruses from clades A, B and C with a breadth of 58%, putting it in the same range as second-generation bNAbs derived from adults, but its potency was lower. BF520.1 was shown to target the base of the V3 loop at the N332 supersite. V3 glycan-binding, second-generation mAb, PGT121 when compared had a geometric mean of IC₅₀=0.02 µg/ml for 2/12 viruses it neutralized at a potency of 67%. The infant-derived antibodies had a lower rate of somatic hypermutation (SHM) and no indels compared to adult-derived anti-V3 mAbs. This study shows that bnAbs can develop without SHM or prolonged affinity maturation. Simonich2016 (neutralization, structure)
PGT121: This study examined the neutralization of group N, O, and P primary isolates of HIV-1 by diverse antibodies. Cross-group neutralization was observed only with the bNAbs targeting the N160 glycan-V1/V2 site. Four group O isolates, 1 group N isolate, and the group P isolates were neutralized by PG9 and/or PG16 or PGT145 at low concentrations. None of the non-M primary isolates were neutralized by bNAbs targeting other regions, except 10E8, which weakly neutralized 2 group N isolates, and 35O22 which neutralized 1 group O isolate. Bispecific bNAbs (PG9-iMab and PG16-iMab) very efficiently neutralized all non-M isolates with IC₅₀ below 1 ug/mL, except for 2 group O strains. Anti-V3 bNAb PGT121 was unable to neutralize any of the 16 tested non-M primary isolates at an IC₅₀< 10µg/ml. Morgand2015 (neutralization, subtype comparisons)
PGT121: The neutralization of 14 bnAbs was assayed against a global panel of 12 or 17 Env pseudoviruses. From IC₅₀, IC₈₀, IC₉₀, and IC₉₉ values, the slope of the dose-response curve was calculated. Each class of Ab had a fairly consistent slope. Neutralization breadth was strongly correlated with slope. An IIP (Instantaneous Inhibitory Potential) value was calculated, based on both the slope and IC50, and this value may be predictive of clinical efficacy. PGT121, a V3-glycan bnAb belonged to a group with slopes >1. Webb2015 (neutralization)
PGT121: This study evaluated the binding of 15 inferred germline (gl) precursors of bNAbs that are directed to different epitope clusters, to 3 soluble native-like SOSIP.664 Env trimers - BG505, B41 and ZM197M. The trimers bound to some gl precursors, particularly those of V1V2-targeted Abs. These trimers may be useful for designing immunogens able to target gl precursors. V3 glycan-binding gl-PGT121 precursor did not bind to any trimers. Sliepen2015 (binding affinity, antibody lineage)
PGT121: Bispecific IgGs were produced, composed of independent antigen-binding fragments with a common Fc region. Parental antibodies of several classes were assessed (VRC07, 10E8, PGT121, PG9-16). A bispecific antibody composed of VRC07 x PG9-16 displayed the most favorable profile, neutralizing 97% of viruses with a median IC₅₀ of 0.055 ug/ml. This bispecific IgG also demonstrated pharmacokinetic parameters comparable to those of the parental bNAbs when administered to rhesus macaques. These results suggest that IgG-based bispecific antibodies are promising candidates for HIV prevention and treatment. Against a panel of 206 resistant and sensitive viruses, PGT121 neutralizes with median IC₈₀ of 0.094 µg/ml. Bispecific with VRC07 median neutralization is 0.355; while in physical combination with the same bNAb, median neutralization of the antibodies is 0.199 µg/ml respectively. Asokan2015 (neutralization, immunotherapy, bispecific/trispecific)
PGT121: A panel of antibodies was tested for binding, stability, and ADCC activity on HIV-infected cells. The differences in killing efficiency were linked to changes in binding of the antibody and the accessibility of the Fc region when bound to infected cells. Ab PGT121 had strong ADCC. Bruel2016 (ADCC, binding affinity)
PGT121: This review summarized bNAb immunotherapy studies. Several bnAbs have been shown to decrease viremia in vivo, and are a prospect for preventative vaccinations. bNAbs have 3 possible immune effector functions: (1) directly neutralizing virions, (2) mediating anti-viral activity through Fc-FcR interactions, and (3) binding to viral antigen to be taken up by dendritic cells. In contrast to anti-HIV mAbs, antibodies against host cell CD4 and CCR5 receptors (iMab and PRO 140) are hindered by their short half-life in vivo. MAb PGT121 has been associated with viral suppression in a study of rhesus macaques. Halper-Stromberg2016 (immunotherapy, review)
PGT121: This study reported that early passive immunotherapy can eliminate early viral foci and thereby prevent the establishment of viral reservoirs. HIV-1–specific human neutralizing mAbs (NmAbs) were used as a post-exposure therapy in an infant macaque model for intrapartum MTCT, inoculated orally with the SHIV SF162P3. On days 1, 4, 7 and 10 post virus exposure, animals were injected with NmAbs and quantified systemic distribution 24 h after Ab administration. Replicating virus was found in multiple tissues by day 1 in untreated animals. A cocktail of PGT121 and VRC07-523, at total doses of 10 mg/kg (5 mg/kg each Ab) and 40 mg/kg (20 mg/kg each Ab) was administered. It was found that PGT121 concentrations in the plasma were consistently higher at both doses than those of VRC07-523. The NmAb cocktail IC₅₀ against SHIVSF162P3 in the TZM-bl assay was 0.0128 μg/ml. There was no evidence of virus rebound in the plasma immunity and all NmAb-treated macaques were free of virus in blood and tissues 6 months after exposure. Experimental data sets have been provided in supplement. Hessell2016 (neutralization, acute/early infection, immunotherapy, mother-to-infant transmission)
PGT121: X-ray and EM structures of inferred precursors of the PGT121 family were generated (inferred intermediate heavy chains 3H, 9H, and 32H were paired with the intermediate light chain 3L). The N137 glycan was determined to be a major factor in affinity maturation of the PGT121 family (affinity maturation was primarily focused on avoiding, accommodating, or binding the N137 glycan). The antibody approach angle differed in the two main branches of the PGT121 lineage. A 3.0 Å crystal structure of a recombinant BG505 SOSIP.664 HIV-1 trimer with a PGT121 family member (3H+109L Ab) was determined. Garces2015 (vaccine antigen design, structure, antibody lineage)
PGT121: The study's goal was to produce modified SOSIP trimers that would reduce the exposure - and, by inference, the immunogenicity - of non-NAb epitopes such as V3. The binding of several modified SOSIP trimers was compared among 12 neutralizing (PG9, PG16, PGT145, PGT121, PGT126, 2G12, PGT135, VRC01, CH103, CD4, IgG2, PGT151, 35O22) and 3 non-neutralizing antibodies (14e, 19b, b6). The V3 non-NAbs 447-52D, 39F, 14e, and 19b bound less well to all A316W variant trimers compared to wild-type trimers. Mice and rabbits immunized with modified, stabilized SOSIP trimers developed fewer V3 Ab responses than those immunized with native trimers. deTaeye2015 (antibody binding site)
PGT121: PGT121 was produced in a plant system and tested as immunotherapy in non-human primates. In African green monkeys, subcutaneously administered PGT121 exhibited a longer serum half-life than intravenous administration and was more consistent than intramuscular delivery. Subcutaneous administration resulted in sterilizing protection from SHIV challenge in 6 of 6 rhesus macaques, while 3 of 4 control animals became infected. Administration of PGT121 after intravaginal challenge did not provide statistically-significant protection. Rosenberg2016 (vaccine antigen design, immunotherapy)
PGT121: Double, triple or quadruple combinations of fifteen bNAbs that target 4 distinct epitope regions: the CD4 binding site (3BNC117, VRC01, VRC07, VRC07-523, VRC13), the V3-glycan supersite (10–1074, 10-1074V, PGT121, PGT128), the V1/V2-glycan site (PG9, PGT145, PGDM1400, CAP256-VRC26.08, CAP256-VRC26.25), and the gp41 MPER epitope (10E8) were studied. Their neutralization potency and breadth were assayed against a panel of 200 acute/early subtype C strains, and compared to a novel, highly accurate predictive mathematical model (no-overlap Bliss Hill model, CombiNaber tool, LANL HIV Immunology database). These data were used to predict the best combinations of bNAbs for immunotherapy. Wagh2016 (neutralization, immunotherapy)
PGT121: VRC07-523:BNabs were tested for their ability to suppress viremia during acute infection in rhesus macaques. Most effective by all virological parameters was dual therapy with VRC07-523 + PGT121. Therapy with VRC01 also curtailed viral replication, but less consistently. These finding support the use of MAbs for immunotherapy during early infection. Bolton2015 (acute/early infection, immunotherapy)
PGT121: The IGHV region is central to Ag binding and consists of 48 functional genes. IGHV repertoire of 28 HIV-infected South African women, 13 of whom developed bNAbs, was sequenced. Novel IGHV repertoires were reported, including 85 entirely novel sequences and 38 sequences that matched rearranged sequences in non-IMGT databases. There were no significant differences in germline IGHV repertoires between individuals who do and do not develop bNAbs. IGHV gene usage of multiple well known HIV-1 bNAbs was also analyzed and 14 instances were identified where the novel non-IMGT alleles identified in this study, provided the same or a better match than their currently defined IMGT allele. For PGT121 the published IMGT predicted allele was IGHV4-59*01 and alternate allele predicted from IGHV alleles in 28 South African individuals was IGHV4-59*1m2, with T94C nucleotide and Y32H amino acid change. Scheepers2015 (antibody lineage)
PGT121: This study describes a new level of complexity in antibody recognition of the mixed glycan-protein epitopes of the N332 region of HIV gp120. A combination of three antibody families that target the high-mannose patch can lead to 99% neutralization coverage of a large panel of viruses containing the N332/334 glycan site and up to 66% coverage for viruses that lack the N332/334 glycan site. PGT121 was able to neutralize all the N334 glycan site variants in the panel except for the isolates JR-CSF and 92TH021. The PGT121 family of antibodies neutralized N332 glycan site viruses more effectively overall than the PGT128 family or PGT135. Sok2014a (antibody interactions, glycosylation)
PGT121: A subset of bNAbs that inhibit both cell-free and cell-mediated infection in primary CD4+ lymphocytes have been identified. These antibodies target either the CD4-binding site or the glycan/V3 loop on HIV-1 gp120 and act at low concentrations by inhibiting multiple steps of viral cell to cell transmission. This property of blocking viral transmission to plasmacytoid DCs and interfering with type-I IFN production should be considered an important characteristic defining the potency for therapeutic or prophylactic antiviral strategies. PGT121 was not effective in blocking cell to cell transmission of virus. Malbec2013
PGT121: Incomplete neutralization may decrease the ability of bnAbs to protect against HIV exposure. In order to determine the extent of non-sigmoidal slopes that plateau at <100% neutralization, a panel of 24 bnMAbs targeting different regions on Env was tested in a quantitative pseudovirus neutralization assay on a panel of 278 viral clones. All bNAbs had some viruses that they neutralized with a plateau <100%, but those targeting the V2 apex and MPER did so more often. All bnMAbs assayed had some viruses for which they had incomplete neutralization and non-sigmoidal neutralization curves. bNAbs were grouped into 3 groups based on their neutralization curves: group 1 antibodies neutralized more than 90% of susceptible viruses to >95% (PGT121-123, PGT125-128, PGT136, PGV04); group 2 was less effective, resulting in neutralization of 60-84% of susceptible viruses to >95% (b12, PGT130-131, PGT135, PGT137, PGT141-143, PGT145, 2G12, PG9); group 3 neutralized only 36-60% of susceptible viruses to >95% (PG16, PGT144, 2F5, 4E10). McCoy2015 (neutralization)
PGT121: Vectored Immuno Prophylaxis (VIP), involves passive immunization by viral vector-mediated delivery of genes encoding bnAbs for in vivo expression. Robust protection against virus infection was observed in preclinical settings when animals were given VIP to express monoclonal neutralizing Abs. This review article surveyed the status of antibody gene transfer, VIP experiments against HIV and its related virus conduced in humanized mice and macaque monkeys, and discuss the pros and cons of VIP and its opportunities and challenges towards clinical applications to control HIV/AIDS endemics. Yang2014 (immunoprophylaxis, review, antibody gene transfer)
PGT121: The ability of bNAbs to inhibit the HIV cell entry was tested for b12, VRC01,VRC03, PG9, PG16, PGT121, 2F5, 10E8, 2G12. Among them, PGT121, VRC01, and VRC03 potently inhibited HIV entry into CD4+ T cells of infected individuals whose viremia was suppressed by ART. Chun2014 (immunotherapy)
PGT121: A gp140 trimer mosaic construct (MosM) was produced based on M group sequences. MosM bound to CD4 as well as multiple bNAbs, including VRC01, 3BNC117, PGT121, PGT126, PGT145, PG9 and PG16. The immunogenicity of this construct, both alone and mixed together with a clade C Env protein vaccine, suggest a promising approach for improving NAb responses. Nkolola2014 (vaccine antigen design)
PGT121: Structural studies were performed for bNAbs PGT121, PGT122, and PGT123. The 3 bNAbs have very similar structures, but are divergent in their variable domain sequences. Julien2013b (antibody sequence, structure)
PGT121: Computational prediction of bNAb epitopes from experimental neutralization activity data is presented. The approach relies on compressed sensing (CS) and mutual information (MI) methodologies and requires the sequences of the viral strains but does not require structural information. For PGT121, CS predicted 4 and MI predicted 3 positions, overlapping in position 332. Ferguson2013 (computational epitope prediction, broad neutralizer)
PGT121: Clade A Env sequence, BG505, was identified to bind to bNAbs representative of most of the known NAb classes. This sequence is the best natural sequence match (73%) to the MRCA sequence from 19 Env sequences derived from PG9 and PG16 MAbs' donor. A point mutation at position L111A of BG505 enabled more efficient production of a stable gp120 monomer, preserving the major neutralization epitopes. The antisera produced by this adjuvanted formulation of gp120 competed with bnAbs from 3 classes of non-overlapping epitopes. PGT121 showed very high neutralization titer against BG505 pseudovirus in a competitive binding assay as shown in Table 1. Hoffenberg2013 (antibody interactions, glycosylation, neutralization)
PGT121: This is a review of identified bNAbs, including the ontogeny of B cells that give rise to these antibodies. Breadth and magnitude of neutralization, unique features and similar bNAbs are listed. PGT121 is a V3-glycan Ab, with breadth 53%, IC₅₀ 0.08 μg per ml, and its unique feature is that it recognizes V1/V2 and V3 glycan. Similar MAbs include PGT122 and PGT123. Kwong2013 (review)
PGT121: A highly conserved mechanism of exposure of ADCC epitopes on Env is reported, showing that binding of Env and CD4 within the same HIV-1 infected cell effectively exposes these epitopes. The mechanism might explain the evolutionary advantage of downregulation of cell surface CD4v by the Vpu and Nef proteins. PGT121 was used in CD4 coexpression and competitive binding assay. Veillette2014 (ADCC)
PGT121: To identify bNAbs that have lower mutation frequencies of known bNAbs, but maintain high potency and moderate breadth, linage evolution of bNAbs PGT121-134 was studied with a novel phylogenetic method ImmuniTree. Selected heavy and light chain clones of PGT121 were paired and tested for neutralization breadth and potency on a cross-clade 74-virus panel. A positive correlation between the somatic hypermutation and the development of neutralization breadth and potency was reported. 3H+3L and 32H+3L were compared against PGT121 and b12 to evaluate neutralization activity of the intermediate divergence. 3H+3L showed 15fold less potency and 32H+3L showed 3 fold less potency than PGT121. Sok2013 (antibody lineage)
PGT121: The newly identified and defined epitope for PGT151 family MAbs binds to a site of vulnerability that does not overlap with any other bnAb epitopes. PGT121 wwas used as an anti-gp41 mAb to compare its binding with other PGT151 family Abs. Blattner2014
PGT121: 8 bNAbs (PGT151 family) were isolated from an elite neutralizer. The new bNAbs bind a previously unknown glycan-dependent epitope on the prefusion conformation of gp41. These MAbs are specific for the cleaved Env trimer and do not recognize uncleaved Env trimer. PGT121 was used for comparison. Falkowska2014
PGT121: Profound therapeutic efficacy of PGT121 and PGT121-containing monoclonal antibody cocktails was demonstrated in chronically SHIV-SF162P3 infected rhesus monkeys. Cocktails included 1, 2, and 3 mAb combinations of PGT121, 3BNC117 and b12. A single monoclonal antibody infusion containing PGT121 alone or in a cocktail led to up to 3.1 log decline of plasma viral RNA in 7 days and reduced proviral DNA in peripheral blood, gastrointestinal mucosa and lymph nodes without the development of viral resistance. A subset of animals maintained long-term virological control in the absence of further monoclonal antibody infusions. Barouch2013a (immunotherapy)
PGT121: This is a review of a satellite symposium at the AIDS Vaccine 2012 conference, focusing on antibody gene transfer. David Baltimore presented results in which humanized mice given vectored immunoprophylaxis (VIP) to express antibody b12 or VRC01 were challenged with the REJO.c transmitted founder strain. Substantial protection was noted in mice expressing VRC01 but not in those expressing b12, consistent with results obtained in vitro for these antibody-strain combinations. Also, all mice expressing VRC07G54W were protected against 20 consecutive weekly challenges with the REJO.c transmitted molecular founder strain. Balazs2013 (immunoprophylaxis)
PGT121: Diversity of Ab recognition at the N332 site was assessed using chimeric antibodies made of heavy and light chains of N332-directed bNAbs PGT121-137. Recognition was good when heavy and light chains came from the same donor, and poor when they came from different donors, indicating multiple modes of recognition. Pancera2013a (chimeric antibody)
PGT121: "Neutralization fingerprints" for 30 neutralizing antibodies were determined using a panel of 34 diverse HIV-1 strains. 10 antibody clusters were defined: VRC01-like, PG9-like, PGT128-like, 2F5-like, 10E8-like and separate clusters for b12, CD4, 2G12, HJ16, 8ANC195. This mAb belongs to PGT128-like cluster. Georgiev2013 (neutralization)
PGT121: This study uncovered a potentially significant contribution of V_H replacement products which are highly enriched in IgH genes for the generation of anti-HIV Abs including anti-gp41, anti-V3 loop, anti-gp120, CD4i and PGT Abs. IgH encoding PGT Abs are likely generated from multiple rounds of V_H replacements. The details of PGT121 V_H replacement products in IgH gene and mutations and amino acid sequence analysis are described in Table 1, Table 2 and Fig 4. Liao2013a (antibody sequence)
PGT121: Protective potency of PGT121 was evaluated in vivo in rhesus macaques. PGT121 efficiently protected against high-dose challenge of SHIV SF162P3 in macaques. Sterilizing immunity was observed in 5/5 animals administered 5 mg/kg antibody dose and in 3/5 animals administered 0.2 mg/kg, suggesting that a protective serum concentration for PG121 is in the single-digit mg/mL. PGT121was effective at serum concentration 600-fold lower than for 2G12 and 100-fold lower than for b12. Moldt2012a (immunoprophylaxis)
PGT121: Neutralization profiles of 7 bnAbs were analyzed against 45 Envs (A, C, D clades), obtained soon after infection (median 59 days). The transmitted variants have distinct characteristics compared to variants from chronic patients, such as shorter variable loops and fewer potential N-linked glycosylation sites (PNGS). PGT121 neutralized only 24% of these viruses. However, PGT128 and NIH45-46W did not compete for neutralization and a combination of these MAbs neutralized 96% of these viruses, with PGT121 neutralizing the only 2 viruses not neutralized by this combination. This suggests that optimal neutralization coverage of transmitted variants can be achieved by combining a potent CD4bs NAb with one or more glycan-dependent MAbs. Goo2012 (antibody interactions, neutralization, rate of progression)
PGT121: A computational tool (Antibody Database) identifying Env residues affecting antibody activity was developed. As input, the tool incorporates antibody neutralization data from large published pseudovirus panels, corresponding viral sequence data and available structural information. The model consists of a set of rules that provide an estimated IC₅₀ based on Env sequence data, and important residues are found by minimizing the difference between logarithms of actual and estimated IC₅₀. The program was validated by analysis of MAb 8ANC195, which had unknown specificity. Predicted critical N-glycosylation for 8ANC195 were confirmed in vitro and in humanized mice. The key associated residues for each MAb are summarized in the Table 1 of the paper and also in the Neutralizing Antibody Contexts & Features tool at Los Alamos Immunology Database. West2013 (glycosylation, computational epitope prediction)
PGT121: Identification of broadly neutralizing antibodies, their epitopes on the HIV-1 spike, the molecular basis for their remarkable breadth, and the B cell ontogenies of their generation and maturation are reviewed. Ontogeny and structure-based classification is presented, based on MAb binding site, type (structural mode of recognition), class (related ontogenies in separate donors) and family (clonal lineage). This MAb's classification: gp120 glycan-V3 site, type not yet determined, PGT121 class, PGT121 family. Kwong2012 (review, structure, broad neutralizer)
PGT121: This review discusses how analysis of infection and vaccine candidate-induced antibodies and their genes may guide vaccine design. This MAb is listed as V3 epitope involving carbohydrates bnAb, isolated after 2009 by neutralization screening of cultured, unselected IgG+ memory B cells. Bonsignori2012b (vaccine antigen design, vaccine-induced immune responses, review)
PGT121: Glycan Asn332-targeting broadly cross-neutralizing (BCN) antibodies were studied in 2 C-clade infected women. The ASn332 glycan was absent on infecting virus, but the BCN epitope with Asn332 evolved within 6 months though immune escape from earlier antibodies. Plasma from the subject CAP177 neutralized 88% of a large multi-subtype panel of 225 heterologous viruses, whereas CAP 314 neutralized 46% of 41 heterologous viruses but failed to neutralize viruses that lack glycan at 332. PGT121 targets Asn332 to neutralize. Moore2012 (neutralization, escape)
PGT121: Several antibodies including 10-1074 were isolated from B-cell clone encoding PGT121, from a clade A-infected African donor using YU-2 gp140 trimers as bait. These antibodies were segregated into PGT121-like (PGT121-123 and 9 members) and 10-1074-like (20 members) groups distinguished by sequence, binding affinity, carbohydrate recognition, neutralizing activity, the V3 loop binding and the role of glycans in epitope formation. The epitopes for both groups contain a potential N-linked glycosylation site (PNGS) at Asn332gp120 and the base of the V3 loop of the gp120 subunit of the HIV spike. However, the 10-1074–like Abs required an intact PNGS at Asn332gp120 for their neutralizing activity, whereas PGT121-like antibodies were able to neutralize some viral strains lacking the Asn332gp120 PNGS. PGT121 clonal members recognize V3 loop and the Asn332 gp120 associated glycan. Crystal structures of unliganded PGT121 and 10-1074 were compared and revealed differential carbohydrate recognition maps to a cleft between (CDR)H2 and CDRH3, occupied by a complex-type N-glycan. Detail information on the binding and neutralization assays are described in the figures S2-S11. Mouquet2012a (glycosylation, neutralization, binding affinity, broad neutralizer)
PGT121: Antigenic properties of undigested VLPs and endo H-digested WT trimer VLPs were compared. Binding to E168K+ N189A WT VLPs was stronger than binding to the parent WT VLPs, uncleaved VLPs. There was no significant correlation between E168K+N189A WT VLP binding and PGT121 neutralization, while trimer VLP ELISA binding and neutralization exhibited a significant correlation. BN-PAGE shifts using digested E168K + N189A WT trimer VLPs exhibited prominence compared to WT VLPs. Tong2012 (neutralization, binding affinity)
PGT121: Neutralizing antibody repertoires of 4 HIV-infected donors with remarkably broad and potent neutralizing responses were probed. 17 new monoclonal antibodies that neutralize broadly across clades were rescued. These MAbs were not polyreactive. All MAbs exhibited broad cross-clade neutralizing activity, but several showed exceptional potency. PGT121 neutralized 70% of 162 isolates from major HIV clades at IC50<50 μg/ml, which was lower than 93% by VRC01, but the median antibody concentration required to inhibit HIV activity by 50% or 90% (IC50 and IC90 values) was almost 10-fold lower (that is, more potent) that of PG9, VRC01 and PGV04, and 100-fold lower than that of b12, 2G12 and 4E10. PGT MAbs 121-123, 130, 131 and 135-137 bound to monomeric gp120 and competed with glycan-specific 2G12 MAb and all MAbs except PGT 135-137 also competed with a V3-loop-specific antibody and did not bind to gp120ΔV3, suggesting that their epitopes are in proximity to or contiguous with V3. Glycan array analysis and alanine substitution analysis suggested that that PGT121 binds to a protein epitope along the gp120 polypeptide backbone that is conformationally dependent on the N332 glycan or that the glycan contributes more strongly to binding in the context of the intact protein. Walker2011 (antibody binding site, antibody generation, variant cross-reactivity, broad neutralizer)

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Caskey2017 Marina Caskey, Till Schoofs, Henning Gruell, Allison Settler, Theodora Karagounis, Edward F. Kreider, Ben Murrell, Nico Pfeifer, Lilian Nogueira, Thiago Y. Oliveira, Gerald H. Learn, Yehuda Z. Cohen, Clara Lehmann, Daniel Gillor, Irina Shimeliovich, Cecilia Unson-O'Brien, Daniela Weiland, Alexander Robles, Tim Kummerle, Christoph Wyen, Rebeka Levin, Maggi Witmer-Pack, Kemal Eren, Caroline Ignacio, Szilard Kiss, Anthony P. West, Jr., Hugo Mouquet, Barry S. Zingman, Roy M. Gulick, Tibor Keler, Pamela J. Bjorkman, Michael S. Seaman, Beatrice H. Hahn, Gerd Fätkenheuer, Sarah J. Schlesinger, Michel C. Nussenzweig, and Florian Klein. Antibody 10-1074 Suppresses Viremia in HIV-1-Infected Individuals. Nat. Med., 23(2):185-191, Feb 2017. PubMed ID: 28092665. Show all entries for this paper.

Deshpande2016 Suprit Deshpande, Shilpa Patil, Rajesh Kumar, Tandile Hermanus, Kailapuri G. Murugavel, Aylur K. Srikrishnan, Suniti Solomon, Lynn Morris, and Jayanta Bhattacharya. HIV-1 Clade C Escapes Broadly Neutralizing Autologous Antibodies with N332 Glycan Specificity by Distinct Mechanisms. Retrovirology, 13(1):60, 30 Aug 2016. PubMed ID: 27576440. Show all entries for this paper.

Garces2015 Fernando Garces, Jeong Hyun Lee, Natalia de Val, Alba Torrents de la Pena, Leopold Kong, Cristina Puchades, Yuanzi Hua, Robyn L. Stanfield, Dennis R. Burton, John P. Moore, Rogier W. Sanders, Andrew B. Ward, and Ian A. Wilson. Affinity Maturation of a Potent Family of HIV Antibodies Is Primarily Focused on Accommodating or Avoiding Glycans. Immunity, 43(6):1053-1063, 15 Dec 2015. PubMed ID: 26682982. Show all entries for this paper.

Gristick2016 Harry B. Gristick, Lotta von Boehmer, Anthony P. West, Jr., Michael Schamber, Anna Gazumyan, Jovana Golijanin, Michael S. Seaman, Gerd Fätkenheuer, Florian Klein, Michel C. Nussenzweig, and Pamela J. Bjorkman. Natively Glycosylated HIV-1 Env Structure Reveals New Mode for Antibody Recognition of the CD4-Binding Site. Nat. Struct. Mol. Biol., 23(10):906-915, Oct 2016. PubMed ID: 27617431. Show all entries for this paper.

Halper-Stromberg2016 Ariel Halper-Stromberg and Michel C Nussenzweig. Towards HIV-1 Remission: Potential Roles for Broadly Neutralizing Antibodies. J. Clin. Invest., 126(2):415-423, Feb 2016. PubMed ID: 26752643. Show all entries for this paper.

Hessell2016 Ann J. Hessell, J. Pablo Jaworski, Erin Epson, Kenta Matsuda, Shilpi Pandey, Christoph Kahl, Jason Reed, William F. Sutton, Katherine B. Hammond, Tracy A. Cheever, Philip T. Barnette, Alfred W. Legasse, Shannon Planer, Jeffrey J. Stanton, Amarendra Pegu, Xuejun Chen, Keyun Wang, Don Siess, David Burke, Byung S. Park, Michael K. Axthelm, Anne Lewis, Vanessa M. Hirsch, Barney S. Graham, John R. Mascola, Jonah B. Sacha, and Nancy L. Haigwood. Early Short-Term Treatment with Neutralizing Human Monoclonal Antibodies Halts SHIV Infection in Infant Macaques. Nat. Med., 22(4):362-368, Apr 2016. PubMed ID: 26998834. Show all entries for this paper.

Hsu2021 Denise C. Hsu, John W. Mellors, and Sandhya Vasan. Can Broadly Neutralizing HIV-1 Antibodies Help Achieve an ART-Free Remission? Front Immunol, 12:710044 doi, 2021. PubMed ID: 34322136 Show all entries for this paper.

Julien2013b Jean-Philippe Julien, Devin Sok, Reza Khayat, Jeong Hyun Lee, Katie J. Doores, Laura M. Walker, Alejandra Ramos, Devan C. Diwanji, Robert Pejchal, Albert Cupo, Umesh Katpally, Rafael S. Depetris, Robyn L. Stanfield, Ryan McBride, Andre J. Marozsan, James C. Paulson, Rogier W. Sanders, John P. Moore, Dennis R. Burton, Pascal Poignard, Andrew B. Ward, and Ian A. Wilson. Broadly Neutralizing Antibody PGT121 Allosterically Modulates CD4 Binding via Recognition of the HIV-1 gp120 V3 Base and Multiple Surrounding Glycans. PLoS Pathog., 9(5):e1003342, 2013. PubMed ID: 23658524. Show all entries for this paper.

Khan2018 Salar N. Khan, Devin Sok, Karen Tran, Arlette Movsesyan, Viktoriya Dubrovskaya, Dennis R. Burton, and Richard T. Wyatt. Targeting the HIV-1 Spike and Coreceptor with Bi- and Trispecific Antibodies for Single-Component Broad Inhibition of Entry. J. Virol., 92(18), 15 Sep 2018. PubMed ID: 29976677. Show all entries for this paper.

Longo2016 Nancy S. Longo, Matthew S. Sutton, Andrea R. Shiakolas, Javier Guenaga, Marissa C. Jarosinski, Ivelin S. Georgiev, Krisha McKee, Robert T. Bailer, Mark K. Louder, Sijy O'Dell, Mark Connors, Richard T. Wyatt, John R. Mascola, and Nicole A. Doria-Rose. Multiple Antibody Lineages in One Donor Target the Glycan-V3 Supersite of the HIV-1 Envelope Glycoprotein and Display a Preference for Quaternary Binding. J. Virol., 90(23):10574-10586, 1 Dec 2016. PubMed ID: 27654288. Show all entries for this paper.

Mahomed2020 Sharana Mahomed, Nigel Garrett, Quarraisha A. Karim, Nonhlanhla Y. Zuma, Edmund Capparelli, Cheryl Baxter, Tanuja Gengiah, Derseree Archary, Natasha Samsunder, Nicole D. Rose, Penny Moore, Carolyn Williamson, Dan H. Barouch, Patricia E. Fast, Bruno Pozzetto, Catherine Hankins, Kevin Carlton, Julie Ledgerwood, Lynn Morris, John Mascola, and Salim Abdool Karim. Assessing the safety and pharmacokinetics of the anti-HIV monoclonal antibody CAP256V2LS alone and in combination with VRC07-523LS and PGT121 in South African women: study protocol for the first-in-human CAPRISA 012B phase I clinical trial. BMJ Open, 10(11):e042247 doi, Nov 2020. PubMed ID: 33243815 Show all entries for this paper.

Malbec2013 Marine Malbec, Françoise Porrot, Rejane Rua, Joshua Horwitz, Florian Klein, Ari Halper-Stromberg, Johannes F. Scheid, Caroline Eden, Hugo Mouquet, Michel C. Nussenzweig, and Olivier Schwartz. Broadly Neutralizing Antibodies That Inhibit HIV-1 Cell to Cell Transmission. J. Exp. Med., 210(13):2813-2821, 16 Dec 2013. PubMed ID: 24277152. Show all entries for this paper.

Moldt2012a Brian Moldt, Eva G. Rakasz, Niccole Schultz, Po-Ying Chan-Hui, Kristine Swiderek, Kimberly L. Weisgrau, Shari M. Piaskowski, Zachary Bergman, David I. Watkins, Pascal Poignard, and Dennis R. Burton. Highly Potent HIV-Specific Antibody Neutralization In Vitro Translates into Effective Protection against Mucosal SHIV Challenge In Vivo. Proc. Natl. Acad. Sci. U.S.A., 109(46):18921-18925, 13 Nov 2012. PubMed ID: 23100539. Show all entries for this paper.

Pancera2013a Marie Pancera, Yongping Yang, Mark K. Louder, Jason Gorman, Gabriel Lu, Jason S. McLellan, Jonathan Stuckey, Jiang Zhu, Dennis R. Burton, Wayne C. Koff, John R. Mascola, and Peter D. Kwong. N332-Directed Broadly Neutralizing Antibodies Use Diverse Modes of HIV-1 Recognition: Inferences from Heavy-Light Chain Complementation of Function. PLoS One, 8(2):e55701, 2013. PubMed ID: 23431362. Show all entries for this paper.

Patel2018 Shabnum Patel, Elizabeth Chorvinsky, Shuroug Albihani, Conrad Russell Cruz, R. Brad Jones, Elizabeth J. Shpall, David M. Margolis, Richard F. Ambinder, and Catherine M. Bollard. HIV-Specific T Cells Generated from Naive T Cells Suppress HIV In Vitro and Recognize Wide Epitope Breadths. Mol. Ther., 26(6):1435-1446, 6 Jun 2018. PubMed ID: 29724686. Show all entries for this paper.

Prigent2018 Julie Prigent, Annaëlle Jarossay, Cyril Planchais, Caroline Eden, Jérémy Dufloo, Ayrin Kök, Valérie Lorin, Oxana Vratskikh, Thérèse Couderc, Timothée Bruel, Olivier Schwartz, Michael S. Seaman, Ohlenschläger, Jordan D. Dimitrov, and Hugo Mouquet. Conformational Plasticity in Broadly Neutralizing HIV-1 Antibodies Triggers Polyreactivity. Cell Rep., 23(9):2568-2581, 29 May 2018. PubMed ID: 29847789. Show all entries for this paper.

Rosenberg2016 Yvonne J. Rosenberg, David C. Montefiori, Celia C. LaBranche, Mark G. Lewis, Markus Sack, Jonathan P. Lees, and Xiaoming Jiang. Protection against SHIV Challenge by Subcutaneous Administration of the Plant-Derived PGT121 Broadly Neutralizing Antibody in Macaques. PLoS One, 11(3):e0152760, 2016. PubMed ID: 27031108. Show all entries for this paper.

Scheepers2015 Cathrine Scheepers, Ram K. Shrestha, Bronwen E. Lambson, Katherine J. L. Jackson, Imogen A. Wright, Dshanta Naicker, Mark Goosen, Leigh Berrie, Arshad Ismail, Nigel Garrett, Quarraisha Abdool Karim, Salim S. Abdool Karim, Penny L. Moore, Simon A. Travers, and Lynn Morris. Ability to Develop Broadly Neutralizing HIV-1 Antibodies Is Not Restricted by the Germline Ig Gene Repertoire. J. Immunol., 194(9):4371-4378, 1 May 2015. PubMed ID: 25825450. Show all entries for this paper.

Schiffner2018 Torben Schiffner, Jesper Pallesen, Rebecca A. Russell, Jonathan Dodd, Natalia de Val, Celia C. LaBranche, David Montefiori, Georgia D. Tomaras, Xiaoying Shen, Scarlett L. Harris, Amin E. Moghaddam, Oleksandr Kalyuzhniy, Rogier W. Sanders, Laura E. McCoy, John P. Moore, Andrew B. Ward, and Quentin J. Sattentau. Structural and Immunologic Correlates of Chemically Stabilized HIV-1 Envelope Glycoproteins. PLoS Pathog., 14(5):e1006986, May 2018. PubMed ID: 29746590. Show all entries for this paper.

Schommers2020 Philipp Schommers, Henning Gruell, Morgan E. Abernathy, My-Kim Tran, Adam S. Dingens, Harry B. Gristick, Christopher O. Barnes, Till Schoofs, Maike Schlotz, Kanika Vanshylla, Christoph Kreer, Daniela Weiland, Udo Holtick, Christof Scheid, Markus M. Valter, Marit J. van Gils, Rogier W. Sanders, Jörg J. Vehreschild, Oliver A. Cornely, Clara Lehmann, Gerd Fätkenheuer, Michael S. Seaman, Jesse D. Bloom, Pamela J. Bjorkman, and Florian Klein. Restriction of HIV-1 Escape by a Highly Broad and Potent Neutralizing Antibody. Cell, 180(3):471-489.e22, 6 Feb 2020. PubMed ID: 32004464. Show all entries for this paper.

Sok2013 Devin Sok, Uri Laserson, Jonathan Laserson, Yi Liu, Francois Vigneault, Jean-Philippe Julien, Bryan Briney, Alejandra Ramos, Karen F. Saye, Khoa Le, Alison Mahan, Shenshen Wang, Mehran Kardar, Gur Yaari, Laura M. Walker, Birgitte B. Simen, Elizabeth P. St. John, Po-Ying Chan-Hui, Kristine Swiderek, Steven H. Kleinstein, Galit Alter, Michael S. Seaman, Arup K. Chakraborty, Daphne Koller, Ian A. Wilson, George M. Church, Dennis R. Burton, and Pascal Poignard. The Effects of Somatic Hypermutation on Neutralization and Binding in the PGT121 Family of Broadly Neutralizing HIV Antibodies. PLoS Pathog, 9(11):e1003754, 2013. PubMed ID: 24278016. Show all entries for this paper.

Sok2014a Devin Sok, Katie J. Doores, Bryan Briney, Khoa M. Le, Karen L. Saye-Francisco, Alejandra Ramos, Daniel W. Kulp, Jean-Philippe Julien, Sergey Menis, Lalinda Wickramasinghe, Michael S. Seaman, William R. Schief, Ian A. Wilson, Pascal Poignard, and Dennis R. Burton. Promiscuous Glycan Site Recognition by Antibodies to the High-Mannose Patch of gp120 Broadens Neutralization of HIV. Sci. Transl. Med., 6(236):236ra63, 14 May 2014. PubMed ID: 24828077. Show all entries for this paper.

Sok2016 Devin Sok, Matthias Pauthner, Bryan Briney, Jeong Hyun Lee, Karen L. Saye-Francisco, Jessica Hsueh, Alejandra Ramos, Khoa M. Le, Meaghan Jones, Joseph G. Jardine, Raiza Bastidas, Anita Sarkar, Chi-Hui Liang, Sachin S. Shivatare, Chung-Yi Wu, William R. Schief, Chi-Huey Wong, Ian A. Wilson, Andrew B. Ward, Jiang Zhu, Pascal Poignard, and Dennis R. Burton. A Prominent Site of Antibody Vulnerability on HIV Envelope Incorporates a Motif Associated with CCR5 Binding and Its Camouflaging Glycans. Immunity, 45(1):31-45, 19 Jul 2016. PubMed ID: 27438765. Show all entries for this paper.

Steinhardt2018 James J. Steinhardt, Javier Guenaga, Hannah L. Turner, Krisha McKee, Mark K. Louder, Sijy O'Dell, Chi-I Chiang, Lin Lei, Andrey Galkin, Alexander K. Andrianov, Nicole A. Doria-Rose, Robert T. Bailer, Andrew B. Ward, John R. Mascola, and Yuxing Li. Rational Design of a Trispecific Antibody Targeting the HIV-1 Env with Elevated Anti-Viral Activity. Nat. Commun., 9(1):877, 28 Feb 2018. PubMed ID: 29491415. Show all entries for this paper.

Stephenson2016 Kathryn E. Stephenson and Dan H. Barouch. Broadly Neutralizing Antibodies for HIV Eradication. Curr. HIV/AIDS Rep., 13(1):31-37, Feb 2016. PubMed ID: 26841901. Show all entries for this paper.

Stephenson2021 Kathryn E. Stephenson, Boris Julg, C. Sabrina Tan, Rebecca Zash, Stephen R. Walsh, Charlotte-Paige Rolle, Ana N. Monczor, Sofia Lupo, Huub C. Gelderblom, Jessica L. Ansel, Diane G. Kanjilal, Lori F. Maxfield, Joseph Nkolola, Erica N. Borducchi, Peter Abbink, Jinyan Liu, Lauren Peter, Abishek Chandrashekar, Ramya Nityanandam, Zijin Lin, Alessandra Setaro, Joseph Sapiente, Zhilin Chen, Lisa Sunner, Tyler Cassidy, Chelsey Bennett, Alicia Sato, Bryan Mayer, Alan S. Perelson, Allan deCamp, Frances H. Priddy, Kshitij Wagh, Elena E. Giorgi, Nicole L. Yates, Roberto C. Arduino, Edwin DeJesus, Georgia D. Tomaras, Michael S. Seaman, Bette Korber, and Dan H. Barouch. Safety, Pharmacokinetics and Antiviral Activity of PGT121, a Broadly Neutralizing Monoclonal Antibody Against HIV-1: A Randomized, Placebo-Controlled, Phase 1 Clinical Trial. Nat. Med., 27(10):1718-1724, Oct 2021. PubMed ID: 34621054. Show all entries for this paper.

Wagh2018 Kshitij Wagh, Michael S. Seaman, Marshall Zingg, Tomas Fitzsimons, Dan H. Barouch, Dennis R. Burton, Mark Connors, David D. Ho, John R. Mascola, Michel C. Nussenzweig, Jeffrey Ravetch, Rajeev Gautam, Malcolm A. Martin, David C. Montefiori, and Bette Korber. Potential of Conventional \& Bispecific Broadly Neutralizing Antibodies for Prevention of HIV-1 Subtype A, C \& D Infections. PLoS Pathog., 14(3):e1006860, Mar 2018. PubMed ID: 29505593. Show all entries for this paper.

Wilson2021 Andrew Wilson, Leyn Shakhtour, Adam Ward, Yanqin Ren, Melina Recarey, Eva Stevenson, Maria Korom, Colin Kovacs, Erika Benko, R. Brad Jones, and Rebecca M. Lynch. Characterizing the Relationship Between Neutralization Sensitivity and env Gene Diversity During ART Suppression. Front Immunol, 12:710327 doi, 2021. PubMed ID: 34603284 Show all entries for this paper.

Witt2017 Kristen C. Witt, Luis Castillo-Menendez, Haitao Ding, Nicole Espy, Shijian Zhang, John C. Kappes, and Joseph Sodroski. Antigenic Characterization of the Human Immunodeficiency Virus (HIV-1) Envelope Glycoprotein Precursor Incorporated into Nanodiscs. PLoS One, 12(2):e0170672, 2017. PubMed ID: 28151945. Show all entries for this paper.

Yang2014 Lili Yang and Pin Wang. Passive Immunization against HIV/AIDS by Antibody Gene Transfer. Viruses, 6(2):428-447, Feb 2014. PubMed ID: 24473340. Show all entries for this paper.

Yu2018 Wen-Han Yu, Peng Zhao, Monia Draghi, Claudia Arevalo, Christina B. Karsten, Todd J. Suscovich, Bronwyn Gunn, Hendrik Streeck, Abraham L. Brass, Michael Tiemeyer, Michael Seaman, John R. Mascola, Lance Wells, Douglas A. Lauffenburger, and Galit Alter. Exploiting Glycan Topography for Computational Design of Env Glycoprotein Antigenicity. PLoS Comput. Biol., 14(4):e1006093, Apr 2018. PubMed ID: 29677181. Show all entries for this paper.

Zhang2022 Baoshan Zhang, Jason Gorman, Sijy O’Dell, Leland F. Damron, Krisha McKee, Mangaiarkarasi Asokan, Amarendra Pegu, Bob C. Lin, Cara W. Chao, Xuejun Chen, Lucio Gama, Vera B. Ivleva, William H. Law, Cuiping Liu, Mark K. Louder, Stephen D. Schmidt, Chen-Hsiang Shen, Wei Shi, Judith A. Stein, Michael S. Seaman, Adrian B. McDermott, Kevin Carlton, John R. Mascola, Peter D. Kwong, Q. Paula Lei, and Nicole A. Doria-Rose. Engineering of {HIV-1} Neutralizing Antibody {CAP256V2LS} for Manufacturability and Improved Half Life, , :, 22 Apr 2022. Show all entries for this paper.

Silver2019 Zachary A. Silver, Gordon M. Dickinson, Michael S. Seaman, and Ronald C. Desrosiers. A Highly Unusual V1 Region of Env in an Elite Controller of HIV Infection. J. Virol., 93(10), 15 May 2019. PubMed ID: 30842322. Show all entries for this paper.

Displaying record number 2636

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MAb ID	PGT122 (PGT-122)
HXB2 Location	Env	Env Epitope Map
Author Location
Epitope
Subtype	A
Ab Type	gp120 V3 // V3 glycan (V3g)
Neutralizing	P View neutralization details
Contacts and Features	View contacts and features
Species (Isotype)	human(IgG)
Patient	Donor 17
Immunogen	HIV-1 infection
Keywords	antibody binding site, antibody gene transfer, antibody generation, antibody interactions, antibody lineage, antibody sequence, assay or method development, binding affinity, broad neutralizer, chimeric antibody, computational epitope prediction, escape, glycosylation, immunoprophylaxis, neutralization, review, structure, vaccine antigen design, vaccine-induced immune responses, variant cross-reactivity

Notes

Showing 21 of 21 notes.

PGT122: This review discusses the identification of super-Abs, where and how such Abs may be best applied and future directions for the field. PGT122 was isolated from human B cell clones and is functionally similar to super-Abs PGT121, PGT128 and PGT135. Antigenic region V3 glycan (Table:1). Walker2018 (antibody binding site, review, broad neutralizer)
PGT122: A systems glycobiology approach was applied to reverse engineer the relationship between bNAb binding and glycan effects on Env proteins. Glycan occupancy was interrogated across every potential N-glycan site in 94 recombinant gp120 antigens. Using a Bayesian machine learning algorithm, bNAb-specific glycan footprints were identified and used to design antigens that selectively alter bNAb antigenicity. The novel synthesized antigens uccessfully bound to target bNAbs with enhanced and selective antigenicity. Yu2018 (glycosylation, vaccine antigen design)
PGT122: Env trimers were engineered with selective deglycosylation around the CD4 binding site to see if they could be useful vaccine antigens. The neutralization of glycan-deleted trimers was tested for a set of bnAbs (PG9, PGT122, PGT135, b12, CH103, HJ16, VRC01, VRC13, PGT151, 8ANC195, 35O22), and the antigens elicited potent neutralization based on the CD4 supersite. A crystal structure was made of one of these Env trimers bound to Fabs 35O22 and 3H+109L. Guinea pigs vaccinated with these antigens achieved neutralization of deglycosylated Envs. Glycan-deleted Env trimers may be useful as priming antigens to increase the frequency of CD4 site-directed antibodies. Zhou2017 (glycosylation, neutralization, vaccine antigen design, vaccine-induced immune responses)
PGT122: Crystal structures of the HIV-1 Env trimer with fully processed and native glycosylation are presented, complexed with the V3-loop bNAb 10-1074 and IOMA, a new CD4bs bNAb. There were fine specificity differences between bNAb 10-1074 and PGT121-family members. PGT122 was two-fold more potent against strains including the N156 PNGS, whereas 10-1074 was four-fold more potent against strains lacking the N156 PNGS. Gristick2016 (glycosylation)
PGT122: HIV-1 bNAb eptiope networks were predicted using 4 algorithms informed by neutralization assays using 282 Env from multiclade viruses. Patch clusters of possible Ab epitope regions were tested for significant sensitivity by site-directed mutagenesis. Epitope (Ab binding site) networks of critical Env residues for 21 bNAb (b12, PG9, PG16, PGT121, PGT122, PGT123, PGT125, PGT126, PGT127, PGT128, PGT130, PGT131, PGT135, PGT136, PGT137, PGT141, PGT142, PGT143, PGT144, PGT145 and PGV04) were delineated and found to be located mostly in variable loops of gp120, particularly in V1/V2. Evans2014 (antibody binding site, computational epitope prediction)
PGT122: A comprehensive antigenic map of the cleaved trimer BG505 SOSIP.664 was made by bNAb cross-competition. Epitope clusters at the CD4bs, quaternary V1/V2 glycan, N332-oligomannose patch and new gp120-gp41 interface and their interactions were delineated. Epitope overlap, proximal steric inhibition, allosteric inhibition or reorientation of glycans were seen in Ab cross-competition. Thus bNAb binding to trimers can affect surfaces beyond their epitopes. PGT122, PGT121, PGT123, PGT125, PGT126 and PGT128, all N332-V3 glycan oligomannose patch-binding bNAbs, were strongly, reciprocally competitive with one another. PGT122 inhibited binding of V1/V2 glycan cluster-Abs like PG9 strongly, but in a non-reciprocal manner and markedly but incompletely inhibited CD4-IgG2. Derking2015 (antibody interactions, neutralization, binding affinity, structure)
PGT122: A new trimeric immunogen, BG505 SOSIP.664 gp140, was developed that bound and activated most known neutralizing antibodies but generally did not bind antibodies lacking neuralizing activity. This highly stable immunogen mimics the Env spike of subtype A transmitted/founder (T/F) HIV-1 strain, BG505. Anti-V3 glycan bNAb PGT122, neutralized BG505.T332N, the pseudoviral equivalent of the immunogen BG505 SOSIP.664 gp140, and was shown to recognize and bind the immunogen too. Sanders2013 (assay or method development, neutralization, binding affinity)
PGT122: X-ray and EM structures of inferred precursors of the PGT121 family were generated (inferred intermediate heavy chains 3H, 9H, and 32H were paired with the intermediate light chain 3L). The N137 glycan was determined to be a major factor in affinity maturation of the PGT121 family (affinity maturation was primarily focused on avoiding, accommodating, or binding the N137 glycan). The antibody approach angle differed in the two main branches of the PGT121 lineage. A 3.0 Å crystal structure of a recombinant BG505 SOSIP.664 HIV-1 trimer with a PGT121 family member (3H+109L Ab) was determined. Garces2015 (vaccine antigen design, structure, antibody lineage)
PGT122: The IGHV region is central to Ag binding and consists of 48 functional genes. IGHV repertoire of 28 HIV-infected South African women, 13 of whom developed bNAbs, was sequenced. Novel IGHV repertoires were reported, including 85 entirely novel sequences and 38 sequences that matched rearranged sequences in non-IMGT databases. There were no significant differences in germline IGHV repertoires between individuals who do and do not develop bNAbs. IGHV gene usage of multiple well known HIV-1 bNAbs was also analyzed and 14 instances were identified where the novel non-IMGT alleles identified in this study, provided the same or a better match than their currently defined IMGT allele. For PGT122 the published IMGT predicted allele was IGHV4-59*01 and alternate allele predicted from IGHV alleles in 28 South African individuals was IGHV4-59*1m2, with T94C nucleotide and Y32H amino acid change. Scheepers2015 (antibody lineage)
PGT122: This study describes a new level of complexity in antibody recognition of the mixed glycan-protein epitopes of the N332 region of HIV gp120. A combination of three antibody families that target the high-mannose patch can lead to 99% neutralization coverage of a large panel of viruses containing the N332/334 glycan site and up to 66% coverage for viruses that lack the N332/334 glycan site. PGT122 neutralized N334 viruses to an intermediate degree. Sok2014a (antibody interactions, glycosylation)
PGT122: Incomplete neutralization may decrease the ability of bnAbs to protect against HIV exposure. In order to determine the extent of non-sigmoidal slopes that plateau at <100% neutralization, a panel of 24 bnMAbs targeting different regions on Env was tested in a quantitative pseudovirus neutralization assay on a panel of 278 viral clones. All bNAbs had some viruses that they neutralized with a plateau <100%, but those targeting the V2 apex and MPER did so more often. All bnMAbs assayed had some viruses for which they had incomplete neutralization and non-sigmoidal neutralization curves. bNAbs were grouped into 3 groups based on their neutralization curves: group 1 antibodies neutralized more than 90% of susceptible viruses to >95% (PGT121-123, PGT125-128, PGT136, PGV04); group 2 was less effective, resulting in neutralization of 60-84% of susceptible viruses to >95% (b12, PGT130-131, PGT135, PGT137, PGT141-143, PGT145, 2G12, PG9); group 3 neutralized only 36-60% of susceptible viruses to >95% (PG16, PGT144, 2F5, 4E10). McCoy2015 (neutralization)
PGT122: Vectored Immuno Prophylaxis (VIP), involves passive immunization by viral vector-mediated delivery of genes encoding bnAbs for in vivo expression. Robust protection against virus infection was observed in preclinical settings when animals were given VIP to express monoclonal neutralizing Abs. This review article surveyed the status of antibody gene transfer, VIP experiments against HIV and its related virus conduced in humanized mice and macaque monkeys, and discuss the pros and cons of VIP and its opportunities and challenges towards clinical applications to control HIV/AIDS endemics. Yang2014 (immunoprophylaxis, review, antibody gene transfer)
PGT122: Structural studies were performed for bNAbs PGT121, PGT122, and PGT123. The 3 bNAbs have very similar structures, but are divergent in their variable domain sequences. Binding by PGT122 depends on the N332 glycan PGT122 interacts with the gp120 outer domain at a more vertical angle than the previously-characterized PGT128. Julien2013b (antibody sequence, structure)
PGT122: Clade A Env sequence, BG505, was identified to bind to bNAbs representative of most of the known NAb classes. This sequence is the best natural sequence match (73%) to the MRCA sequence from 19 Env sequences derived from PG9 and PG16 MAbs' donor. A point mutation at position L111A of BG505 enabled more efficient production of a stable gp120 monomer, preserving the major neutralization epitopes. The antisera produced by this adjuvanted formulation of gp120 competed with bnAbs from 3 classes of non-overlapping epitopes. PGT122 showed very high neutralization titer against BG505 pseudovirus in a competitive binding assay as shown in Table 1. Reduced PGT122 binding to mutated BG505 T332 was rescued by a glycosylated N residue, revealing a glycan binding epitope. Hoffenberg2013 (antibody interactions, glycosylation, neutralization)
PGT122: To identify bNAbs that have lower mutation frequencies of known bNAbs, but maintain high potency and moderate breadth, linage evolution of bNAbs PGT121-134 was studied with a novel phylogenetic method ImmuniTree. This Ab showed partial loss of neutralization potency when used without FRL3 insertion against a cross-lade 6 virus panel. Sok2013 (antibody lineage)
PGT122: Diversity of Ab recognition at the N332 site was assessed using chimeric antibodies made of heavy and light chains of N332-directed bNAbs PGT121-137. Recognition was good when heavy and light chains came from the same donor, and poor when they came from different donors, indicating multiple modes of recognition. Pancera2013a (chimeric antibody)
PGT122: This study uncovered a potentially significant contribution of V_H replacement products which are highly enriched in IgH genes for the generation of anti-HIV Abs including anti-gp41, anti-V3 loop, anti-gp120, CD4i and PGT Abs. IgH encoding PGT Abs are likely generated from multiple rounds of V_H replacements. The details of PGT122 V_H replacement products in IgH gene and mutations and amino acid sequence analysis are described in Table 1, Table 2 and Fig 4. Liao2013a (antibody sequence)
PGT122: Identification of broadly neutralizing antibodies, their epitopes on the HIV-1 spike, the molecular basis for their remarkable breadth, and the B cell ontogenies of their generation and maturation are reviewed. Ontogeny and structure-based classification is presented, based on MAb binding site, type (structural mode of recognition), class (related ontogenies in separate donors) and family (clonal lineage). This MAb's classification: gp120 glycan-V3 site, type not yet determined, PGT121 class, PGT121 family. Kwong2012 (review, structure, broad neutralizer)
PGT122: This review discusses how analysis of infection and vaccine candidate-induced antibodies and their genes may guide vaccine design. This MAb is listed as V3 epitope involving carbohydrates bnAb, isolated after 2009 by neutralization screening of cultured, unselected IgG+ memory B cells. Bonsignori2012b (vaccine antigen design, vaccine-induced immune responses, review)
PGT122: Glycan Asn332-targeting broadly cross-neutralizing (BCN) antibodies were studied in 2 C-clade infected women. The ASn332 glycan was absent on infecting virus, but the BCN epitope with Asn332 evolved within 6 months though immune escape from earlier antibodies. Plasma from the subject CAP177 neutralized 88% of a large multi-subtype panel of 225 heterologous viruses, whereas CAP 314 neutralized 46% of 41 heterologous viruses but failed to neutralize viruses that lack glycan at 332. PGT122 targets Asn332 to neutralize. Moore2012 (neutralization, escape)
PGT122: Neutralizing antibody repertoires of 4 HIV-infected donors with remarkably broad and potent neutralizing responses were probed. 17 new monoclonal antibodies that neutralize broadly across clades were rescued. These MAbs were not polyreactive. All MAbs exhibited broad cross-clade neutralizing activity, but several showed exceptional potency. PGT122 neutralized 65% of 162 isolates from major HIV clades at IC50<50 μg/ml, which was lower than 93% by VRC01, but the median antibody concentration required to inhibit HIV activity by 50% or 90% (IC50 and IC90 values) was almost 10-fold lower (that is, more potent) that of PG9, VRC01 and PGV04, and 100-fold lower than that of b12, 2G12 and 4E10. PGT MAbs 121-123, 130, 131 and 135-137 bound to monomeric gp120 and competed with glycan-specific 2G12 MAb and all MAbs except PGT 135-137 also competed with a V3-loop-specific antibody and did not bind to gp120ΔV3, suggesting that their epitopes are in proximity to or contiguous with V3. Glycan array analysis and alanine substitution analysis suggested that that PGT122 binds to a protein epitope along the gp120 polypeptide backbone that is conformationally dependent on the N332 glycan or that the glycan contributes more strongly to binding in the context of the intact protein. Walker2011 (antibody binding site, antibody generation, variant cross-reactivity, broad neutralizer)

References

Showing 21 of 21 references.

Yang2014 Lili Yang and Pin Wang. Passive Immunization against HIV/AIDS by Antibody Gene Transfer. Viruses, 6(2):428-447, Feb 2014. PubMed ID: 24473340. Show all entries for this paper.

Displaying record number 2637

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MAb ID	PGT123 (PGT-123)
HXB2 Location	Env	Env Epitope Map
Author Location
Epitope
Subtype	A
Ab Type	gp120 V3 // V3 glycan (V3g)
Neutralizing	P View neutralization details
Contacts and Features	View contacts and features
Species (Isotype)	human(IgG)
Patient	Donor 17
Immunogen	HIV-1 infection
Keywords	antibody binding site, antibody gene transfer, antibody generation, antibody interactions, antibody lineage, antibody sequence, assay or method development, binding affinity, broad neutralizer, chimeric antibody, computational epitope prediction, escape, glycosylation, immunoprophylaxis, neutralization, review, structure, vaccine antigen design, vaccine-induced immune responses, variant cross-reactivity

Notes

Showing 25 of 25 notes.

PGT123: This study demonstrated that bNAb signatures can be utilized to engineer HIV-1 Env vaccine immunogens eliciting Ab responses with greater neutralization breadth. Data from four large virus panels were used to comprehensively map viral signatures associated with bNAb sensitivity, hypervariable region characteristics, and clade effects. The bNAb signatures defined for the V2 epitope region were then employed to inform immunogen design in a proof-of-concept exploration of signature-based epitope targeted (SET) vaccines. V2 bNAb signature-guided mutations were introduced into Env 459C to create a trivalent vaccine which resulted in increased breadth of NAb responses compared with Env 459C alone. PGT123 was used for machine learning regression prediction and to analyze statistical details (Table S4). Bricault2019 (antibody binding site, vaccine antigen design, computational epitope prediction, broad neutralizer)
PGT123: This review discusses the identification of super-Abs, where and how such Abs may be best applied and future directions for the field. PGT123 was isolated from human B cell clones and is functionally similar to super-Abs PGT121, PGT128 and PGT135. Antigenic region V3 glycan (Table:1). Walker2018 (antibody binding site, review, broad neutralizer)
PGT123: A systems glycobiology approach was applied to reverse engineer the relationship between bNAb binding and glycan effects on Env proteins. Glycan occupancy was interrogated across every potential N-glycan site in 94 recombinant gp120 antigens. Using a Bayesian machine learning algorithm, bNAb-specific glycan footprints were identified and used to design antigens that selectively alter bNAb antigenicity. The novel synthesized antigens uccessfully bound to target bNAbs with enhanced and selective antigenicity. Yu2018 (glycosylation, vaccine antigen design)
PGT123: HIV-1 bNAb eptiope networks were predicted using 4 algorithms informed by neutralization assays using 282 Env from multiclade viruses. Patch clusters of possible Ab epitope regions were tested for significant sensitivity by site-directed mutagenesis. Epitope (Ab binding site) networks of critical Env residues for 21 bNAb (b12, PG9, PG16, PGT121, PGT122, PGT123, PGT125, PGT126, PGT127, PGT128, PGT130, PGT131, PGT135, PGT136, PGT137, PGT141, PGT142, PGT143, PGT144, PGT145 and PGV04) were delineated and found to be located mostly in variable loops of gp120, particularly in V1/V2. Evans2014 (antibody binding site, computational epitope prediction)
PGT123: A comprehensive antigenic map of the cleaved trimer BG505 SOSIP.664 was made by bNAb cross-competition. Epitope clusters at the CD4bs, quaternary V1/V2 glycan, N332-oligomannose patch and new gp120-gp41 interface and their interactions were delineated. Epitope overlap, proximal steric inhibition, allosteric inhibition or reorientation of glycans were seen in Ab cross-competition. Thus bNAb binding to trimers can affect surfaces beyond their epitopes. PGT123, PGT122, PGT121, PGT125, PGT126 and PGT128, all N332-V3 glycan oligomannose patch-binding bNAbs, were strongly, reciprocally competitive with one another. They inhibited binding of V1/V2 glycan NAbs strongly, but in a non-reciprocal manner. NIH45-46 non-reciprocally enhanced binding of PGT123. Derking2015 (antibody interactions, neutralization, binding affinity, structure)
PGT123: A new trimeric immunogen, BG505 SOSIP.664 gp140, was developed that bound and activated most known neutralizing antibodies but generally did not bind antibodies lacking neuralizing activity. This highly stable immunogen mimics the Env spike of subtype A transmitted/founder (T/F) HIV-1 strain, BG505. Anti-V3 glycan bNAb PGT123, neutralized BG505.T332N, the pseudoviral equivalent of the immunogen BG505 SOSIP.664 gp140, and was shown to recognize and bind the immunogen too. Sanders2013 (assay or method development, neutralization, binding affinity)
PGT123: The study detailed binding kinetics of the interaction between BG505 SOSIP.664 trimer or its variants (gp120 monomer; first study of disulfide-stabilized variant gp120-gp41_ECTO protomer) and several mAbs, both neutralizing (VRC01, PGV04, PG9, PG16, PGT121, PGT122, PGT123, PGT145, PGT151, 2G12) and non-neutralizing (b6, b12, 14e, 19b, F240). V3-base-dependent bNAb, PGT123, recognized trimer better than protomer and monomer, but dissociated faster from protomer, monomer. Yasmeen2014 (antibody binding site, assay or method development)
PGT123: X-ray and EM structures of inferred precursors of the PGT121 family were generated (inferred intermediate heavy chains 3H, 9H, and 32H were paired with the intermediate light chain 3L). The N137 glycan was determined to be a major factor in affinity maturation of the PGT121 family (affinity maturation was primarily focused on avoiding, accommodating, or binding the N137 glycan). The antibody approach angle differed in the two main branches of the PGT121 lineage. A 3.0 Å crystal structure of a recombinant BG505 SOSIP.664 HIV-1 trimer with a PGT121 family member (3H+109L Ab) was determined. Garces2015 (vaccine antigen design, structure, antibody lineage)
PGT123: The IGHV region is central to Ag binding and consists of 48 functional genes. IGHV repertoire of 28 HIV-infected South African women, 13 of whom developed bNAbs, was sequenced. Novel IGHV repertoires were reported, including 85 entirely novel sequences and 38 sequences that matched rearranged sequences in non-IMGT databases. There were no significant differences in germline IGHV repertoires between individuals who do and do not develop bNAbs. IGHV gene usage of multiple well known HIV-1 bNAbs was also analyzed and 14 instances were identified where the novel non-IMGT alleles identified in this study, provided the same or a better match than their currently defined IMGT allele. For PGT123 the published IMGT predicted allele was IGHV4-59*01 and alternate allele predicted from IGHV alleles in 28 South African individuals was IGHV4-59*1m2, with T94C nucleotide and Y32H amino acid change. Scheepers2015 (antibody lineage)
PGT123: This study describes a new level of complexity in antibody recognition of the mixed glycan-protein epitopes of the N332 region of HIV gp120. A combination of three antibody families that target the high-mannose patch can lead to 99% neutralization coverage of a large panel of viruses containing the N332/334 glycan site and up to 66% coverage for viruses that lack the N332/334 glycan site. PGT123 neutralized N334 viruses to an intermediate degree. Sok2014a (antibody interactions, glycosylation)
PGT123: Incomplete neutralization may decrease the ability of bnAbs to protect against HIV exposure. In order to determine the extent of non-sigmoidal slopes that plateau at <100% neutralization, a panel of 24 bnMAbs targeting different regions on Env was tested in a quantitative pseudovirus neutralization assay on a panel of 278 viral clones. All bNAbs had some viruses that they neutralized with a plateau <100%, but those targeting the V2 apex and MPER did so more often. All bnMAbs assayed had some viruses for which they had incomplete neutralization and non-sigmoidal neutralization curves. bNAbs were grouped into 3 groups based on their neutralization curves: group 1 antibodies neutralized more than 90% of susceptible viruses to >95% (PGT121-123, PGT125-128, PGT136, PGV04); group 2 was less effective, resulting in neutralization of 60-84% of susceptible viruses to >95% (b12, PGT130-131, PGT135, PGT137, PGT141-143, PGT145, 2G12, PG9); group 3 neutralized only 36-60% of susceptible viruses to >95% (PG16, PGT144, 2F5, 4E10). McCoy2015 (neutralization)
PGT123: Vectored Immuno Prophylaxis (VIP), involves passive immunization by viral vector-mediated delivery of genes encoding bnAbs for in vivo expression. Robust protection against virus infection was observed in preclinical settings when animals were given VIP to express monoclonal neutralizing Abs. This review article surveyed the status of antibody gene transfer, VIP experiments against HIV and its related virus conduced in humanized mice and macaque monkeys, and discuss the pros and cons of VIP and its opportunities and challenges towards clinical applications to control HIV/AIDS endemics. Yang2014 (immunoprophylaxis, review, antibody gene transfer)
PGT123: Structural studies were performed for bNAbs PGT121, PGT122, and PGT123. The 3 bNAbs have very similar structures, but are divergent in their variable domain sequences. Julien2013b (antibody sequence, structure)
PGT123: Computational prediction of bNAb epitopes from experimental neutralization activity data is presented. The approach relies on compressed sensing (CS) and mutual information (MI) methodologies and requires the sequences of the viral strains but does not require structural information. For PGT123, CS predicted 10 and MI predicted 3 positions, overlapping in positions 330, 332, 334. Ferguson2013 (computational epitope prediction, broad neutralizer)
PGT123: Clade A Env sequence, BG505, was identified to bind to bNAbs representative of most of the known NAb classes. This sequence is the best natural sequence match (73%) to the MRCA sequence from 19 Env sequences derived from PG9 and PG16 MAbs' donor. A point mutation at position L111A of BG505 enabled more efficient production of a stable gp120 monomer, preserving the major neutralization epitopes. The antisera produced by this adjuvanted formulation of gp120 competed with bnAbs from 3 classes of non-overlapping epitopes. PGT123 showed moderate neutralization titer against BG505 pseudovirus in a competitive binding assay as shown in Table 1. Reduced PGT123 binding to mutated BG505 T332 was rescued by a glycosylated N residue, revealing a glycan binding epitope. Hoffenberg2013 (antibody interactions, glycosylation, neutralization)
PGT123: To identify bNAbs that have lower mutation frequencies of known bNAbs, but maintain high potency and moderate breadth, linage evolution of bNAbs PGT121-134 was studied with a novel phylogenetic method ImmuniTree. This Ab showed partial loss of neutralization potency when used without FRL3 insertion against a cross-clade 6 virus panel. Sok2013
PGT123: Diversity of Ab recognition at the N332 site was assessed using chimeric antibodies made of heavy and light chains of N332-directed bNAbs PGT121-137. Recognition was good when heavy and light chains came from the same donor, and poor when they came from different donors, indicating multiple modes of recognition. Pancera2013a (chimeric antibody)
PGT123: "Neutralization fingerprints" for 30 neutralizing antibodies were determined using a panel of 34 diverse HIV-1 strains. 10 antibody clusters were defined: VRC01-like, PG9-like, PGT128-like, 2F5-like, 10E8-like and separate clusters for b12, CD4, 2G12, HJ16, 8ANC195. This mAb belongs to PGT128-like cluster. Georgiev2013 (neutralization)
PGT123: This study uncovered a potentially significant contribution of V_H replacement products which are highly enriched in IgH genes for the generation of anti-HIV Abs including anti-gp41, anti-V3 loop, anti-gp120, CD4i and PGT Abs. IgH encoding PGT Abs are likely generated from multiple rounds of V_H replacements. The details of PGT123 V_H replacement products in IgH gene and mutations and amino acid sequence analysis are described in Table 1, Table 2 and Fig 4. Liao2013a (antibody sequence)
PGT123: Identification of broadly neutralizing antibodies, their epitopes on the HIV-1 spike, the molecular basis for their remarkable breadth, and the B cell ontogenies of their generation and maturation are reviewed. Ontogeny and structure-based classification is presented, based on MAb binding site, type (structural mode of recognition), class (related ontogenies in separate donors) and family (clonal lineage). This MAb's classification: gp120 glycan-V3 site, type not yet determined, PGT121 class, PGT121 family. Kwong2012 (review, structure, broad neutralizer)
PGT123: This review discusses how analysis of infection and vaccine candidate-induced antibodies and their genes may guide vaccine design. This MAb is listed as V3 epitope involving carbohydrates bnAb, isolated after 2009 by neutralization screening of cultured, unselected IgG+ memory B cells. Bonsignori2012b (vaccine antigen design, vaccine-induced immune responses, review)
PGT123: Antigenic properties of 2 biochemically stable and homogeneous gp140 trimers (A clade 92UG037 and C clade CZA97012) were compared with the corresponding gp120 monomers derived from the same percursor sequences. The trimers had nearly all the antigenic properties expected for native viral spikes and were markedly different from monomeric gp120. PGT123 bound trimers and monomers equally well, indicating that the epitope is fully accessible in both forms. Kovacs2012 (antibody binding site, neutralization, binding affinity)
PGT123: Glycan Asn332-targeting broadly cross-neutralizing (BCN) antibodies were studied in 2 C-clade infected women. The ASn332 glycan was absent on infecting virus, but the BCN epitope with Asn332 evolved within 6 months though immune escape from earlier antibodies. Plasma from the subject CAP177 neutralized 88% of a large multi-subtype panel of 225 heterologous viruses, whereas CAP 314 neutralized 46% of 41 heterologous viruses but failed to neutralize viruses that lack glycan at 332. PGT123 targets Asn332 to neutralize. Moore2012 (neutralization, escape)
PGT123: A way to produce conformationally intact, deglycosylated soluble, cleaved recombinant Env trimers by inhibition of the synthesis of complex N-glycans during Env production, followed by treatment with glycosidases under conditions that preserve Env trimer integrity is described to facilitate crystallography and immunogenicity studies. As expected, the glycan-dependent PGT123 did not bind to the deglycosylated trimers. Depetris2012 (glycosylation, binding affinity)
PGT123: Neutralizing antibody repertoires of 4 HIV-infected donors with remarkably broad and potent neutralizing responses were probed. 17 new monoclonal antibodies that neutralize broadly across clades were rescued. These MAbs were not polyreactive. All MAbs exhibited broad cross-clade neutralizing activity, but several showed exceptional potency. PGT123 neutralized 67% of 162 isolates from major HIV clades at IC50<50 μg/ml, which was lower than 93% by VRC01, but the median antibody concentration required to inhibit HIV activity by 50% or 90% (IC50 and IC90 values) was almost 10-fold lower (that is, more potent) that of PG9, VRC01 and PGV04, and 100-fold lower than that of b12, 2G12 and 4E10. PGT MAbs 121-123, 130, 131 and 135-137 bound to monomeric gp120 and competed with glycan-specific 2G12 MAb and all MAbs except PGT 135-137 also competed with a V3-loop-specific antibody and did not bind to gp120ΔV3, suggesting that their epitopes are in proximity to or contiguous with V3. Glycan array analysis and alanine substitution analysis suggested that that PGT123 binds to a protein epitope along the gp120 polypeptide backbone that is conformationally dependent on the N332 glycan or that the glycan contributes more strongly to binding in the context of the intact protein. Walker2011 (antibody binding site, antibody generation, variant cross-reactivity, broad neutralizer)

References

Showing 25 of 25 references.

Depetris2012 Rafael S Depetris, Jean-Philippe Julien, Reza Khayat, Jeong Hyun Lee, Robert Pejchal, Umesh Katpally, Nicolette Cocco, Milind Kachare, Evan Massi, Kathryn B. David, Albert Cupo, Andre J. Marozsan, William C. Olson, Andrew B. Ward, Ian A. Wilson, Rogier W. Sanders, and John P Moore. Partial Enzymatic Deglycosylation Preserves the Structure of Cleaved Recombinant HIV-1 Envelope Glycoprotein Trimers. J. Biol. Chem., 287(29):24239-24254, 13 Jul 2012. PubMed ID: 22645128. Show all entries for this paper.

Yang2014 Lili Yang and Pin Wang. Passive Immunization against HIV/AIDS by Antibody Gene Transfer. Viruses, 6(2):428-447, Feb 2014. PubMed ID: 24473340. Show all entries for this paper.

Displaying record number 2639

Download this epitope record as JSON.

MAb ID	PGT125 (PGT-125)
HXB2 Location	Env	Env Epitope Map
Author Location
Epitope
Subtype	CRF02_AG
Ab Type	gp120 V3 // V3 glycan (V3g)
Neutralizing	P View neutralization details
Contacts and Features	View contacts and features
Species (Isotype)	human(IgG)
Patient	Donor 36
Immunogen	HIV-1 infection
Keywords	antibody binding site, antibody gene transfer, antibody generation, antibody interactions, antibody lineage, antibody polyreactivity, antibody sequence, assay or method development, autoantibody or autoimmunity, binding affinity, broad neutralizer, chimeric antibody, computational epitope prediction, escape, glycosylation, immunoprophylaxis, neutralization, review, structure, vaccine antigen design, vaccine-induced immune responses, variant cross-reactivity

Notes

Showing 25 of 25 notes.

PGT125: This study demonstrated that bNAb signatures can be utilized to engineer HIV-1 Env vaccine immunogens eliciting Ab responses with greater neutralization breadth. Data from four large virus panels were used to comprehensively map viral signatures associated with bNAb sensitivity, hypervariable region characteristics, and clade effects. The bNAb signatures defined for the V2 epitope region were then employed to inform immunogen design in a proof-of-concept exploration of signature-based epitope targeted (SET) vaccines. V2 bNAb signature-guided mutations were introduced into Env 459C to create a trivalent vaccine which resulted in increased breadth of NAb responses compared with Env 459C alone. PGT125 was used for machine learning regression prediction and to analyze statistical details (Table S4). Bricault2019 (antibody binding site, vaccine antigen design, computational epitope prediction, broad neutralizer)
PGT125: This review discusses the identification of super-Abs, where and how such Abs may be best applied and future directions for the field. PGT125 was isolated from human B cell clones and is functionally similar to super-Abs PGT121, PGT128 and PGT135. Antigenic region V3 glycan (Table:1). Walker2018 (antibody binding site, review, broad neutralizer)
PGT125: A systems glycobiology approach was applied to reverse engineer the relationship between bNAb binding and glycan effects on Env proteins. Glycan occupancy was interrogated across every potential N-glycan site in 94 recombinant gp120 antigens. Using a Bayesian machine learning algorithm, bNAb-specific glycan footprints were identified and used to design antigens that selectively alter bNAb antigenicity. The novel synthesized antigens uccessfully bound to target bNAbs with enhanced and selective antigenicity. Yu2018 (glycosylation, vaccine antigen design)
PGT125: Assays of poly- and autoreactivity demonstrated that broadly neutralizing NAbs are significantly more poly- and autoreactive than non-neutralizing NAbs. PGT125 is polyreactive, but not autoreactive. Liu2015a (autoantibody or autoimmunity, antibody polyreactivity)
PGT125: Repetitive immunization of macaques over 3 years with an Env expressing V3-high mannose glycan, CON-S gp140CFI, elicited plasma antibodies neturalizing HIV-1 expressing high mannose glycans only. NAb DH501 was isolated and found to possess a structure where 3 V_H chain CDRs formed a cavity into which the HIV-1 Env V3-glycan could insert. Rhesus DH501 possessed characteristics of V3-glycan bNAb precursors, and it could block PGT125 binding to V3. Saunders2017 (vaccine-induced immune responses, structure)
PGT125: Man₉-V3, a synthetic minimal immunogen designed to reflect the HIV-1 native Env V3-glycan bNAb epitope, binds memory B cells and V3-glycan bNAbs as well as germline bNAbs. Man₉-V3 was used to isolate a bNAb from an HIV-1+ subject and also induce V3-glycan-targeting antibodies in rhesus macaques. Using the crystal structure of PGT128-gp120 Env OD (outer domain), Man₉-V3 glycopeptide was synthesized based on Clade B JRFL with deletion of residues 305-320, retention of P321 and stabilization of disulfide bridge C296-C331. PGT125 neutralization of Man₉-V3 was biphasic. Alam2017 (antibody binding site)
PGT125: This study investigated the ability of native, membrane-expressed JR-FL Env trimers to elicit NAbs. Rabbits were immunized with virus-like particles (VLPs) expressing trimers (trimer VLP sera) and DNA expressing native Env trimer, followed by a protein boost (DNA trimer sera). N197 glycan- and residue 230- removal conferred sensitivity to Trimer VLP sera and DNA trimer sera respectively, showing for the first time that strain-specific holes in the "glycan fence" can allow the development of tier 2 NAbs to native spikes. All 3 sera neutralized via quaternary epitopes and exploited natural gaps in the glycan defenses of the second conserved region of JR-FL gp120. A competitive inter-cluster relationship between PGT125 and CD4bs nAbs was observed. Crooks2015 (glycosylation, neutralization)
PGT125: HIV-1 bNAb eptiope networks were predicted using 4 algorithms informed by neutralization assays using 282 Env from multiclade viruses. Patch clusters of possible Ab epitope regions were tested for significant sensitivity by site-directed mutagenesis. Epitope (Ab binding site) networks of critical Env residues for 21 bNAb (b12, PG9, PG16, PGT121, PGT122, PGT123, PGT125, PGT126, PGT127, PGT128, PGT130, PGT131, PGT135, PGT136, PGT137, PGT141, PGT142, PGT143, PGT144, PGT145 and PGV04) were delineated and found to be located mostly in variable loops of gp120, particularly in V1/V2. Evans2014 (antibody binding site, computational epitope prediction)
PGT125: A comprehensive antigenic map of the cleaved trimer BG505 SOSIP.664 was made by bNAb cross-competition. Epitope clusters at the CD4bs, quaternary V1/V2 glycan, N332-oligomannose patch and new gp120-gp41 interface and their interactions were delineated. Epitope overlap, proximal steric inhibition, allosteric inhibition or reorientation of glycans were seen in Ab cross-competition. Thus bNAb binding to trimers can affect surfaces beyond their epitopes. PGT125, PGT121, PGT122, PGT123, PGT126 and PGT128, all N332-V3 glycan oligomannose patch bNAbs, were strongly, reciprocally competitive with one another. PGT125 also inhibited binding of CD4bs Ab, CH31 and markedly but incompletely inhibited CD4-IgG2. Derking2015 (antibody interactions, neutralization, binding affinity, structure)
PGT125: A new trimeric immunogen, BG505 SOSIP.664 gp140, was developed that bound and activated most known neutralizing antibodies but generally did not bind antibodies lacking neuralizing activity. This highly stable immunogen mimics the Env spike of subtype A transmitted/founder (T/F) HIV-1 strain, BG505. Anti-V3 glycan bNAb PGT125, neutralized BG505.T332N, the pseudoviral equivalent of the immunogen BG505 SOSIP.664 gp140, and was shown to recognize and bind the immunogen too. Sanders2013 (assay or method development, neutralization, binding affinity)
PGT125: Using an escape virus isolated from the PGT125-131 donor, this study found that mutating the V3 core and repositioning critical N-linked glycosylations N295 and N332 could restore virus sensitivity. PGT128 and PGT130 required different sets of changes in order to restore sensitivity, suggesting that this family of bNAbs has two recognition classes (Fig. 2). For example N332 repositioning and 7 amino acid mutations V307I, H308R, E321D, V322I, N325D, P326I, F320H restored PGT128 but not PGT130 virus sensitivity. Krumm2016 (glycosylation, escape)
PGT125: The IGHV region is central to Ag binding and consists of 48 functional genes. IGHV repertoire of 28 HIV-infected South African women, 13 of whom developed bNAbs, was sequenced. Novel IGHV repertoires were reported, including 85 entirely novel sequences and 38 sequences that matched rearranged sequences in non-IMGT databases. There were no significant differences in germline IGHV repertoires between individuals who do and do not develop bNAbs. IGHV gene usage of multiple well known HIV-1 bNAbs was also analyzed and 14 instances were identified where the novel non-IMGT alleles identified in this study, provided the same or a better match than their currently defined IMGT allele. For PGT125 the published IMGT predicted allele was IGHV4-39*07 and alternate allele predicted from IGHV alleles in 28 South African individuals was IGHV4-39*7m2, with synonymous G298C nucleotide change. Scheepers2015 (antibody lineage)
PGT125: This study describes a new level of complexity in antibody recognition of the mixed glycan-protein epitopes of the N332 region of HIV gp120. A combination of three antibody families that target the high-mannose patch can lead to 99% neutralization coverage of a large panel of viruses containing the N332/334 glycan site and up to 66% coverage for viruses that lack the N332/334 glycan site. PGT125 was the most effective at neutralizing viruses with the N334 glycan site. Sok2014a (antibody interactions, glycosylation)
PGT125: Incomplete neutralization may decrease the ability of bnAbs to protect against HIV exposure. In order to determine the extent of non-sigmoidal slopes that plateau at <100% neutralization, a panel of 24 bnMAbs targeting different regions on Env was tested in a quantitative pseudovirus neutralization assay on a panel of 278 viral clones. All bNAbs had some viruses that they neutralized with a plateau <100%, but those targeting the V2 apex and MPER did so more often. All bnMAbs assayed had some viruses for which they had incomplete neutralization and non-sigmoidal neutralization curves. bNAbs were grouped into 3 groups based on their neutralization curves: group 1 antibodies neutralized more than 90% of susceptible viruses to >95% (PGT121-123, PGT125-128, PGT136, PGV04); group 2 was less effective, resulting in neutralization of 60-84% of susceptible viruses to >95% (b12, PGT130-131, PGT135, PGT137, PGT141-143, PGT145, 2G12, PG9); group 3 neutralized only 36-60% of susceptible viruses to >95% (PG16, PGT144, 2F5, 4E10). McCoy2015 (neutralization)
PGT125: Vectored Immuno Prophylaxis (VIP), involves passive immunization by viral vector-mediated delivery of genes encoding bnAbs for in vivo expression. Robust protection against virus infection was observed in preclinical settings when animals were given VIP to express monoclonal neutralizing Abs. This review article surveyed the status of antibody gene transfer, VIP experiments against HIV and its related virus conduced in humanized mice and macaque monkeys, and discuss the pros and cons of VIP and its opportunities and challenges towards clinical applications to control HIV/AIDS endemics. Yang2014 (immunoprophylaxis, review, antibody gene transfer)
PGT125: Computational prediction of bNAb epitopes from experimental neutralization activity data is presented. The approach relies on compressed sensing (CS) and mutual information (MI) methodologies and requires the sequences of the viral strains but does not require structural information. For PGT125, CS predicted 27 positions and MI predicted position 332. Ferguson2013 (computational epitope prediction, broad neutralizer)
PGT125: Clade A Env sequence, BG505, was identified to bind to bNAbs representative of most of the known NAb classes. This sequence is the best natural sequence match (73%) to the MRCA sequence from 19 Env sequences derived from PG9 and PG16 MAbs' donor. A point mutation at position L111A of BG505 enabled more efficient production of a stable gp120 monomer, preserving the major neutralization epitopes. The antisera produced by this adjuvanted formulation of gp120 competed with bnAbs from 3 classes of non-overlapping epitopes. PFT125 showed very high neutralization titer against BG505 pseudovirus in a competitive binding assay as shown in Table 1. Hoffenberg2013 (antibody interactions, glycosylation, neutralization)
PGT125: Diversity of Ab recognition at the N332 site was assessed using chimeric antibodies made of heavy and light chains of N332-directed bNAbs PGT121-137. Recognition was good when heavy and light chains came from the same donor, and poor when they came from different donors, indicating multiple modes of recognition. Pancera2013a (chimeric antibody)
PGT125: This study uncovered a potentially significant contribution of V_H replacement products which are highly enriched in IgH genes for the generation of anti-HIV Abs including anti-gp41, anti-V3 loop, anti-gp120, CD4i and PGT Abs. IgH encoding PGT Abs are likely generated from multiple rounds of V_H replacements. The details of PGT125 V_H replacement products in IgH gene and mutations and amino acid sequence analysis are described in Table 1, Table 2 and Fig 4. Liao2013a (antibody sequence)
PGT125: Identification of broadly neutralizing antibodies, their epitopes on the HIV-1 spike, the molecular basis for their remarkable breadth, and the B cell ontogenies of their generation and maturation are reviewed. Ontogeny and structure-based classification is presented, based on MAb binding site, type (structural mode of recognition), class (related ontogenies in separate donors) and family (clonal lineage). This MAb's classification: gp120 glycan-V3 site, type penetrating CDR H3 binds two glycans and strand, PGT128 class, PGT128 family. Kwong2012 (review, structure, broad neutralizer)
PGT125: This review discusses how analysis of infection and vaccine candidate-induced antibodies and their genes may guide vaccine design. This MAb is listed as V3 epitope involving carbohydrates bnAb, isolated after 2009 by neutralization screening of cultured, unselected IgG+ memory B cells. Bonsignori2012b (vaccine antigen design, vaccine-induced immune responses, review)
PGT125: Glycan shield of HIV Env protein helps to escape the Ab recognition. Several of the PGT BnAbs interact directly with the HIV glycan coat. Crystal structures of Fabs PGT127 and PGT128 showed that the high neutralizing potency was mediated by cross-linking Env trimers on the viral surface. PGT125 binds to Man8/9 glycans on gp120 and potently neutralize across the clades. Pejchal2011 (glycosylation, structure, broad neutralizer)
PGT125: Glycan Asn332-targeting broadly cross-neutralizing (BCN) antibodies were studied in 2 C-clade infected women. The ASn332 glycan was absent on infecting virus, but the BCN epitope with Asn332 evolved within 6 months though immune escape from earlier antibodies. Plasma from the subject CAP177 neutralized 88% of a large multi-subtype panel of 225 heterologous viruses, whereas CAP 314 neutralized 46% of 41 heterologous viruses but failed to neutralize viruses that lack glycan at 332. PGT125 targets Asn332 to neutralize. Moore2012 (neutralization, escape)
PGT125: Antigenic properties of undigested VLPs and endo H-digested WT trimer VLPs were compared. Binding to E168K+ N189A WT VLPs was stronger than binding to the parent WT VLPs, uncleaved VLPs. There was no significant correlation between E168K+N189A WT VLP binding and PGT125 neutralization, while trimer VLP ELISA binding and neutralization exhibited a significant correlation. BN-PAGE shifts using digested E168K + N189A WT trimer VLPs exhibited prominence compared to WT VLPs. Tong2012 (neutralization, binding affinity)
PGT125: Neutralizing antibody repertoires of 4 HIV-infected donors with remarkably broad and potent neutralizing responses were probed. 17 new monoclonal antibodies that neutralize broadly across clades were rescued. These MAbs were not polyreactive. All MAbs exhibited broad cross-clade neutralizing activity, but several showed exceptional potency. PGT125 neutralized 52% of 162 isolates from major HIV clades at IC50<50 μg/ml, which was lower than 93% by VRC01, but the median antibody concentration required to inhibit HIV activity by 50% or 90% (IC50 and IC90 values) was almost 10-fold lower (that is, more potent) that of PG9, VRC01 and PGV04, and 100-fold lower than that of b12, 2G12 and 4E10. PGT MAbs 121-123, 130, 131 and 135-137 bound to monomeric gp120 and competed with glycan-specific 2G12 MAb and all MAbs except PGT 135-137 also competed with a V3-loop-specific antibody and did not bind to gp120ΔV3, suggesting that their epitopes are in proximity to or contiguous with V3. Glycan array analysis revealed that PGT MAbs 125–128 and 130 bound specifically to both Man8GlcNAc2 and Man9GlcNAc2, whereas the remaining antibodies showed no detectable binding to high-mannose glycans. Alanine substitution analysis suggested that N-linked glycans at positions 332 and/or 301 were important for neutralization by PGT MAbs 125–128, 130 and 131, suggesting their direct involvement in epitope formation. Walker2011 (antibody binding site, antibody generation, variant cross-reactivity, broad neutralizer)

References

Showing 25 of 25 references.

Alam2017 S. Munir Alam, Baptiste Aussedat, Yusuf Vohra, R. Ryan Meyerhoff, Evan M. Cale, William E. Walkowicz, Nathan A. Radakovich, Kara Anasti, Lawrence Armand, Robert Parks, Laura Sutherland, Richard Scearce, M. Gordon Joyce, Marie Pancera, Aliaksandr Druz, Ivelin S. Georgiev, Tarra Von Holle, Amanda Eaton, Christopher Fox, Steven G. Reed, Mark Louder, Robert T. Bailer, Lynn Morris, Salim S. Abdool-Karim, Myron Cohen, Hua-Xin Liao, David C. Montefiori, Peter K. Park, Alberto Fernández-Tejada, Kevin Wiehe, Sampa Santra, Thomas B. Kepler, Kevin O. Saunders, Joseph Sodroski, Peter D. Kwong, John R. Mascola, Mattia Bonsignori, M. Anthony Moody, Samuel Danishefsky, and Barton F. Haynes. Mimicry of an HIV Broadly Neutralizing Antibody Epitope with a Synthetic Glycopeptide. Sci. Transl. Med., 9(381), 15 Mar 2017. PubMed ID: 28298421. Show all entries for this paper.

Krumm2016 Stefanie A. Krumm, Hajer Mohammed, Khoa M. Le, Max Crispin, Terri Wrin, Pascal Poignard, Dennis R. Burton, and Katie J. Doores. Mechanisms of Escape from the PGT128 Family of Anti-HIV Broadly Neutralizing Antibodies. Retrovirology, 13:8, 2 Feb 2016. PubMed ID: 26837192. Show all entries for this paper.

Saunders2017 Kevin O. Saunders, Nathan I. Nicely, Kevin Wiehe, Mattia Bonsignori, R. Ryan Meyerhoff, Robert Parks, William E. Walkowicz, Baptiste Aussedat, Nelson R. Wu, Fangping Cai, Yusuf Vohra, Peter K. Park, Amanda Eaton, Eden P. Go, Laura L. Sutherland, Richard M. Scearce, Dan H. Barouch, Ruijun Zhang, Tarra Von Holle, R. Glenn Overman, Kara Anasti, Rogier W. Sanders, M. Anthony Moody, Thomas B. Kepler, Bette Korber, Heather Desaire, Sampa Santra, Norman L. Letvin, Gary J. Nabel, David C. Montefiori, Georgia D. Tomaras, Hua-Xin Liao, S. Munir Alam, Samuel J. Danishefsky, and Barton F. Haynes. Vaccine Elicitation of High Mannose-Dependent Neutralizing Antibodies against the V3-Glycan Broadly Neutralizing Epitope in Nonhuman Primates. Cell Rep., 18(9):2175-2188, 28 Feb 2017. PubMed ID: 28249163. Show all entries for this paper.

Yang2014 Lili Yang and Pin Wang. Passive Immunization against HIV/AIDS by Antibody Gene Transfer. Viruses, 6(2):428-447, Feb 2014. PubMed ID: 24473340. Show all entries for this paper.

Displaying record number 2640

Download this epitope record as JSON.

MAb ID	PGT126 (PGT-126)
HXB2 Location	Env	Env Epitope Map
Author Location
Epitope
Ab Type	gp120 V3 // V3 glycan (V3g)
Neutralizing	P View neutralization details
Contacts and Features	View contacts and features
Species (Isotype)	human(IgG)
Patient	Donor 36
Immunogen	HIV-1 infection
Keywords	ADCC, antibody binding site, antibody gene transfer, antibody generation, antibody interactions, antibody lineage, antibody sequence, assay or method development, binding affinity, broad neutralizer, chimeric antibody, computational epitope prediction, escape, glycosylation, immunoprophylaxis, immunotherapy, neutralization, polyclonal antibodies, review, structure, subtype comparisons, vaccine antigen design, vaccine-induced immune responses, variant cross-reactivity

Notes

Showing 35 of 35 notes.

PGT126: The Chinese HIV Reference Laboratory produced 124 pseudoviruses from patients with subype B, BC, and CRF01 infections. These viruses were assigned to tiers based on their neutralization by a panel of patient sera. Their neutralization sensitivities were also measured against a panel of well-characterized mAbs (2F5, b12, 2G12, 4E10, 10E8, VRC01, VRC-CH31, CH01, PG9, PG16, PGT121, PGT126). Nie2020 (assay or method development, neutralization)
PGT126: Chemoenzymatic synthesis, antigenicity, and immunogenicity of the V3 N334 glycopeptides from HIV-1 A244 gp120 have been reported. A synthetic V3 glycopeptide carrying a N334 high-mannose glycan was recognized by bNAb PGT128 and PGT126 but not by 10-1074. Rabbit immunization with the synthetic three-component A244 glycopeptide immunogen elicited substantial glycan-dependent antibodies with broad reactivity to various HIV-1 gp120/gp140 carrying N332 or N334 glycosylation sites. PGT126 could bind all the V3 glycopeptides carrying a high-mannose glycan but not the glycopeptides carrying the complex-type N-glycan. Cai2018 (glycosylation, vaccine antigen design, structure)
PGT126: This study demonstrated that bNAb signatures can be utilized to engineer HIV-1 Env vaccine immunogens eliciting Ab responses with greater neutralization breadth. Data from four large virus panels were used to comprehensively map viral signatures associated with bNAb sensitivity, hypervariable region characteristics, and clade effects. The bNAb signatures defined for the V2 epitope region were then employed to inform immunogen design in a proof-of-concept exploration of signature-based epitope targeted (SET) vaccines. V2 bNAb signature-guided mutations were introduced into Env 459C to create a trivalent vaccine which resulted in increased breadth of NAb responses compared with Env 459C alone. PGT126 was used for machine learning regression prediction and to analyze statistical details (Table S4). Bricault2019 (antibody binding site, vaccine antigen design, computational epitope prediction, broad neutralizer)
PGT126: This review discusses the identification of super-Abs, where and how such Abs may be best applied and future directions for the field. PGT126 was isolated from human B cell clones and is functionally similar to super-Abs PGT121, PGT128 and PGT135. Antigenic region V3 glycan (Table:1). Walker2018 (antibody binding site, review, broad neutralizer)
PGT126: A systems glycobiology approach was applied to reverse engineer the relationship between bNAb binding and glycan effects on Env proteins. Glycan occupancy was interrogated across every potential N-glycan site in 94 recombinant gp120 antigens. Using a Bayesian machine learning algorithm, bNAb-specific glycan footprints were identified and used to design antigens that selectively alter bNAb antigenicity. The novel synthesized antigens uccessfully bound to target bNAbs with enhanced and selective antigenicity. Yu2018 (glycosylation, vaccine antigen design)
PGT126: A panel of 14 pseudoviruses of subtype CRF01_AE was developed to assess the neutralization of several neutralizing antibodies (b12, PG9, PG16, 4E10, 10E8, 2F5, PGT121, PGT126, 2G12). Neutralization was assessed in both TZM-bl and A3R5 cell-based assays. Most viruses were more susceptible to mAb-neutralization in A3R5 than in the TZM-bl cell-based assay. The increased neutralization sensitivity observed in the A3R5 assay was not linked to the year of virus transmission or to the stages of infection, but chronic viruses from the years 1990-92 were more sensitive to neutralization than the more current viruses, in both assays. Chenine2018 (assay or method development, neutralization, subtype comparisons)
PGT126: SOSIP.664 trimer was modified at V3 positions 306 and 308 by Leucine substitution to create hydrophobic interactions with the tryptophan residue at position 316 and the V1V2 domain. These modifications stabilized the resulting SOSIP.v5.2 S306L R308L trimers. In vivo, the induction of V3 non-NAbs was significantly reduced compared with the SOSIP.v5.2 trimers. S306L plus R308L paired substitutions had no effect on the trimer reactivity of PGT126. deTaeye2018 (broad neutralizer)
PGT126: Three strategies were applied to perturb the structure of Env in order to make the protein more susceptible to neutralization: exposure to cold, Env-activating ligands, and a chaotropic agent. A panel of mAbs (E51, 48d, 17b, 3BNC176, 19b, 447-52D, 39F, b12, b6, PG16, PGT145, PGT126, 35O22, F240, 10E8, 7b2, 2G12) was used to test the neutralization resistance of a panel of subtype B and C pseudoviruses with and without these agents. Both cold and CD4 mimicking agents (CD4Ms) increased the sensitivity of some viruses. The chaotropic agent urea had little effect by itself, but could enhance the effects of cold or CD4Ms. Thus Env destabilizing agents can make Env more susceptible to neutralization and may hold promise as priming vaccine antigens. Johnson2017 (vaccine antigen design)
PGT126: A panel of mAbs (2G12, VRC01, HJ16, 2F5, 4E10, 35O22, PG9, PGT121, PGT126, 10-1074) was tested to compare their efficacy in cell-free versus cell-cell transmission. Almost all bNAbs (with the exception of anti-CD4 mAb Leu3a) blocked cell-free infection with greater potency than cell-cell infection, and showed greater potency in neutralization of cell-free viruses. The lower effectiveness on neutralization was particularly pronounced for transmitted/founder viruses, and less pronounced for chronic and lab-adapted viruses. The study highlights that the ability of an antibody to inhibit cell-cell transmission may be an important consideration in the development of Abs for prophylaxis. Li2017 (immunoprophylaxis, neutralization)
PGT126: This review focuses on the potential role of HIV-1-specific NAbs in preventing HIV-1 infection. Several NAbs have provided protection from infection in SHIV challenge studies in primates: b12, VRC01, VRC07-523LS, 3BNC117, PG9, PGT121, PGT126, 10-1074, 2G12, 4E10, 2F5, 10E8. Pegu2017 (immunoprophylaxis, review)
PGT126: Env residue N197 on the BG505-SOSIP trimer was mutated to test the effect of its glycosylation on the binding kinetics of CD4BS and other mAbs. Removal of the glycan had little effect on the overall structure of the molecule. Its removal resulted in increased binding of CD4 and CD4BS antibodies (VRC01, VRC03, V3-3074), but little effect on bNAbs targeting other epitopes (PG9, PG16, PGT145, 17b, A32, 2G12, PGT121, PGT126). Two CD4BS-binding antibodies tested (b12, F105) had insufficient breadth to bind the BG505-SOSIP trimer. Removal of the N197 glycan may allow for the development of better SOSIP immunogens, particularly to elicit CD4BS-specific Abs. Liang2016 (glycosylation, vaccine antigen design)
PGT126: Chimeric antigen receptors, i.e., fusion proteins made from single-chain antibodies, may be a useful approach to immunotherapy. A set of mAbs were chosen based on their binding to a variety of sites on Env and availability of antibody sequences. The chimeric receptors were created by fusing the antibody's heavy chain, light chain, and two signaling domains into a single molecule. All 7 antibodies used to make the chimeric receptors (10E8, 3BNC117, PGT126, VRC01, X5, PGT128, PG9) showed specific killing of HIV-1 infected cells and suppression of viral replication against a panel of HIV-1 strains. Ali2016 (immunotherapy, chimeric antibody)
PGT126: This study assessed the ADCC activity of antibodies of varied binding types, including CD4bs (b6, b12, VRC01, PGV04, 3BNC117), V2 (PG9, PG16), V3 (PGT126, PGT121, 10-1074), oligomannose (2G12), MPER (2F5, 4E10, 10E8), CD4i (17b, X5), C1/C5 (A32, C11), cluster I (240D, F240), and cluster II (98-6, 126-7). ADCC activity was correlated with binding to Env on the surfaces of virus-infected cells. ADCC was correlated with neutralization, but not always for lab-adapted viruses such as HIV-1 NLA-3. PGT126 had moderate to strong ADCC activity against cells infected with 3 of 3 strains tested. vonBredow2016 (ADCC)
PGT126: HIV-1 bNAb eptiope networks were predicted using 4 algorithms informed by neutralization assays using 282 Env from multiclade viruses. Patch clusters of possible Ab epitope regions were tested for significant sensitivity by site-directed mutagenesis. Epitope (Ab binding site) networks of critical Env residues for 21 bNAb (b12, PG9, PG16, PGT121, PGT122, PGT123, PGT125, PGT126, PGT127, PGT128, PGT130, PGT131, PGT135, PGT136, PGT137, PGT141, PGT142, PGT143, PGT144, PGT145 and PGV04) were delineated and found to be located mostly in variable loops of gp120, particularly in V1/V2. Evans2014 (antibody binding site, computational epitope prediction)
PGT126: PGT145 was used to positively isolate a subtype B Env trimer immunogen, B41 SOSIP.664-D7324, that exists in two conformations, closed and partially open. bNAbs tested against the trimer were able to neutralize the B41 pseudovirus with a wide range of potencies. All tested non-NAbs did not neutralize B41 (IC₅₀ >50µg/ml). V3 glycan bNAb, PGT121, neutralized the B41 pseudovirus and bound B41 trimer. Pugach2015
PGT126: A comprehensive antigenic map of the cleaved trimer BG505 SOSIP.664 was made by bNAb cross-competition. Epitope clusters at the CD4bs, quaternary V1/V2 glycan, N332-oligomannose patch and new gp120-gp41 interface and their interactions were delineated. Epitope overlap, proximal steric inhibition, allosteric inhibition or reorientation of glycans were seen in Ab cross-competition. Thus bNAb binding to trimers can affect surfaces beyond their epitopes. PGT126, PGT121, PGT122, PGT123, PGT125 and PGT128, all N332-V3 glycan oligomannose patch bNAbs, were strongly, reciprocally competitive with one another. PGT126 also inhibited binding of CD4bs Ab, CH31 and markedly but incompletely inhibited CD4-IgG2. Derking2015 (antibody interactions, neutralization, binding affinity, structure)
PGT126: The native-like, engineered trimer BG505 SOSIP.664 induced potent NAbs against conformational epitopes of neutralization-resistant Tier-2 viruses in rabbits and macaques, but induced cross-reactive NAbs against linear V3 epitopes of neutralization-sensitive Tier-1 viruses. A different trimer, B41 SOSIP.664 also induced strong autologous Tier-2 NAb responses in rabbits. Sera from 6/20 BG505 SOSIP.664-D7324 trimer-immunized rabbits were capable of inhibiting VRC01 binding to V3-glycan. 4/4 similarly trimer-immunized macaque sera also inhibited VRC01 binding by >50%. Sanders2015 (antibody generation, neutralization, binding affinity, polyclonal antibodies)
PGT126: A new trimeric immunogen, BG505 SOSIP.664 gp140, was developed that bound and activated most known neutralizing antibodies but generally did not bind antibodies lacking neuralizing activity. This highly stable immunogen mimics the Env spike of subtype A transmitted/founder (T/F) HIV-1 strain, BG505. Anti-V3 glycan bNAb PGT126, neutralized BG505.T332N, the pseudoviral equivalent of the immunogen BG505 SOSIP.664 gp140, and was shown to recognize and bind the immunogen too. Sanders2013 (assay or method development, neutralization, binding affinity)
PGT126: Using an escape virus isolated from the PGT125-131 donor, this study found that mutating the V3 core and repositioning critical N-linked glycosylations N295 and N332 could restore virus sensitivity. PGT128 and PGT130 required different sets of changes in order to restore sensitivity, suggesting that this family of bNAbs has two recognition classes (Fig. 2). For example N332 repositioning and 7 amino acid mutations V307I, H308R, E321D, V322I, N325D, P326I, F320H restored PGT128 but not PGT130 virus sensitivity. Krumm2016 (glycosylation, escape)
PGT126: The IGHV region is central to Ag binding and consists of 48 functional genes. IGHV repertoire of 28 HIV-infected South African women, 13 of whom developed bNAbs, was sequenced. Novel IGHV repertoires were reported, including 85 entirely novel sequences and 38 sequences that matched rearranged sequences in non-IMGT databases. There were no significant differences in germline IGHV repertoires between individuals who do and do not develop bNAbs. IGHV gene usage of multiple well known HIV-1 bNAbs was also analyzed and 14 instances were identified where the novel non-IMGT alleles identified in this study, provided the same or a better match than their currently defined IMGT allele. For PGT126 the published IMGT predicted allele was IGHV4-39*07 and alternate allele predicted from IGHV alleles in 28 South African individuals was IGHV4-39*7m2, with synonymous G298C nucleotide change. Scheepers2015 (antibody lineage)
PGT126: The study's goal was to produce modified SOSIP trimers that would reduce the exposure - and, by inference, the immunogenicity - of non-NAb epitopes such as V3. The binding of several modified SOSIP trimers was compared among 12 neutralizing (PG9, PG16, PGT145, PGT121, PGT126, 2G12, PGT135, VRC01, CH103, CD4, IgG2, PGT151, 35O22) and 3 non-neutralizing antibodies (14e, 19b, b6). The V3 non-NAbs 447-52D, 39F, 14e, and 19b bound less well to all A316W variant trimers compared to wild-type trimers. Mice and rabbits immunized with modified, stabilized SOSIP trimers developed fewer V3 Ab responses than those immunized with native trimers. deTaeye2015 (antibody binding site)
PGT126: This study describes a new level of complexity in antibody recognition of the mixed glycan-protein epitopes of the N332 region of HIV gp120. A combination of three antibody families that target the high-mannose patch can lead to 99% neutralization coverage of a large panel of viruses containing the N332/334 glycan site and up to 66% coverage for viruses that lack the N332/334 glycan site. PGT126 was the most effective at neutralizing viruses with the N334 glycan site. Sok2014a (antibody interactions, glycosylation)
PGT126: Incomplete neutralization may decrease the ability of bnAbs to protect against HIV exposure. In order to determine the extent of non-sigmoidal slopes that plateau at <100% neutralization, a panel of 24 bnMAbs targeting different regions on Env was tested in a quantitative pseudovirus neutralization assay on a panel of 278 viral clones. All bNAbs had some viruses that they neutralized with a plateau <100%, but those targeting the V2 apex and MPER did so more often. All bnMAbs assayed had some viruses for which they had incomplete neutralization and non-sigmoidal neutralization curves. bNAbs were grouped into 3 groups based on their neutralization curves: group 1 antibodies neutralized more than 90% of susceptible viruses to >95% (PGT121-123, PGT125-128, PGT136, PGV04); group 2 was less effective, resulting in neutralization of 60-84% of susceptible viruses to >95% (b12, PGT130-131, PGT135, PGT137, PGT141-143, PGT145, 2G12, PG9); group 3 neutralized only 36-60% of susceptible viruses to >95% (PG16, PGT144, 2F5, 4E10). McCoy2015 (neutralization)
PGT126: Vectored Immuno Prophylaxis (VIP), involves passive immunization by viral vector-mediated delivery of genes encoding bnAbs for in vivo expression. Robust protection against virus infection was observed in preclinical settings when animals were given VIP to express monoclonal neutralizing Abs. This review article surveyed the status of antibody gene transfer, VIP experiments against HIV and its related virus conduced in humanized mice and macaque monkeys, and discuss the pros and cons of VIP and its opportunities and challenges towards clinical applications to control HIV/AIDS endemics. Yang2014 (immunoprophylaxis, review, antibody gene transfer)
PGT126: A gp140 trimer mosaic construct (MosM) was produced based on M group sequences. MosM bound to CD4 as well as multiple bNAbs, including VRC01, 3BNC117, PGT121, PGT126, PGT145, PG9 and PG16. The immunogenicity of this construct, both alone and mixed together with a clade C Env protein vaccine, suggest a promising approach for improving NAb responses. Nkolola2014 (vaccine antigen design)
PGT126: Computational prediction of bNAb epitopes from experimental neutralization activity data is presented. The approach relies on compressed sensing (CS) and mutual information (MI) methodologies and requires the sequences of the viral strains but does not require structural information. For PGT123, CS predicted 6 and MI predicted 3 positions, overlapping in positions 297, 332, 334. Ferguson2013 (computational epitope prediction, broad neutralizer)
PGT126: Clade A Env sequence, BG505, was identified to bind to bNAbs representative of most of the known NAb classes. This sequence is the best natural sequence match (73%) to the MRCA sequence from 19 Env sequences derived from PG9 and PG16 MAbs' donor. A point mutation at position L111A of BG505 enabled more efficient production of a stable gp120 monomer, preserving the major neutralization epitopes. The antisera produced by this adjuvanted formulation of gp120 competed with bnAbs from 3 classes of non-overlapping epitopes. PGT126 showed very high neutralization titer against BG505 pseudovirus in a competitive binding assay as shown in Table 1. Hoffenberg2013 (antibody interactions, glycosylation, neutralization)
PGT126: Diversity of Ab recognition at the N332 site was assessed using chimeric antibodies made of heavy and light chains of N332-directed bNAbs PGT121-137. Recognition was good when heavy and light chains came from the same donor, and poor when they came from different donors, indicating multiple modes of recognition. Pancera2013a (chimeric antibody)
PGT126: "Neutralization fingerprints" for 30 neutralizing antibodies were determined using a panel of 34 diverse HIV-1 strains. 10 antibody clusters were defined: VRC01-like, PG9-like, PGT128-like, 2F5-like, 10E8-like and separate clusters for b12, CD4, 2G12, HJ16, 8ANC195. This mAb belongs to PGT128-like cluster. Georgiev2013 (neutralization)
PGT126: This study uncovered a potentially significant contribution of V_H replacement products which are highly enriched in IgH genes for the generation of anti-HIV Abs including anti-gp41, anti-V3 loop, anti-gp120, CD4i and PGT Abs. IgH encoding PGT Abs are likely generated from multiple rounds of V_H replacements. The details of PGT126 V_H replacement products in IgH gene and mutations and amino acid sequence analysis are described in Table 1, Table 2 and Fig 4. Liao2013a (antibody sequence)
PGT126: Identification of broadly neutralizing antibodies, their epitopes on the HIV-1 spike, the molecular basis for their remarkable breadth, and the B cell ontogenies of their generation and maturation are reviewed. Ontogeny and structure-based classification is presented, based on MAb binding site, type (structural mode of recognition), class (related ontogenies in separate donors) and family (clonal lineage). This MAb's classification: gp120 glycan-V3 site, type penetrating CDR H3 binds two glycans and strand, PGT128 class, PGT128 family. Kwong2012 (review, structure, broad neutralizer)
PGT126: This review discusses how analysis of infection and vaccine candidate-induced antibodies and their genes may guide vaccine design. This MAb is listed as V3 epitope involving carbohydrates bnAb, isolated after 2009 by neutralization screening of cultured, unselected IgG+ memory B cells. Bonsignori2012b (vaccine antigen design, vaccine-induced immune responses, review)
PGT126: Glycan shield of HIV Env protein helps to escape the Ab recognition. Several of the PGT BnAbs interact directly with the HIV glycan coat. Crystal structures of Fabs PGT127 and PGT128 showed that the high neutralizing potency was mediated by cross-linking Env trimers on the viral surface. PGT126 binds to Man8/9 glycans on gp120 and potently neutralize across the clades. Pejchal2011 (glycosylation, structure, broad neutralizer)
PGT126: Glycan Asn332-targeting broadly cross-neutralizing (BCN) antibodies were studied in 2 C-clade infected women. The ASn332 glycan was absent on infecting virus, but the BCN epitope with Asn332 evolved within 6 months though immune escape from earlier antibodies. Plasma from the subject CAP177 neutralized 88% of a large multi-subtype panel of 225 heterologous viruses, whereas CAP 314 neutralized 46% of 41 heterologous viruses but failed to neutralize viruses that lack glycan at 332. PGT126 targets Asn332 to neutralize. Moore2012 (neutralization, escape)
PGT126: Neutralizing antibody repertoires of 4 HIV-infected donors with remarkably broad and potent neutralizing responses were probed. 17 new monoclonal antibodies that neutralize broadly across clades were rescued. These MAbs were not polyreactive. All MAbs exhibited broad cross-clade neutralizing activity, but several showed exceptional potency. PGT126 neutralized 52% of 162 isolates from major HIV clades at IC50<50 μg/ml, which was lower than 93% by VRC01, but the median antibody concentration required to inhibit HIV activity by 50% or 90% (IC50 and IC90 values) was almost 10-fold lower (that is, more potent) that of PG9, VRC01 and PGV04, and 100-fold lower than that of b12, 2G12 and 4E10. PGT MAbs 121-123, 130, 131 and 135-137 bound to monomeric gp120 and competed with glycan-specific 2G12 MAb and all MAbs except PGT 135-137 also competed with a V3-loop-specific antibody and did not bind to gp120ΔV3, suggesting that their epitopes are in proximity to or contiguous with V3. Glycan array analysis revealed that PGT MAbs 125–128 and 130 bound specifically to both Man8GlcNAc2 and Man9GlcNAc2, whereas the remaining antibodies showed no detectable binding to high-mannose glycans. Alanine substitution analysis suggested that N-linked glycans at positions 332 and/or 301 were important for neutralization by PGT MAbs 125–128, 130 and 131, suggesting their direct involvement in epitope formation. Walker2011 (antibody binding site, antibody generation, variant cross-reactivity, broad neutralizer)

References

Showing 35 of 35 references.

Yang2014 Lili Yang and Pin Wang. Passive Immunization against HIV/AIDS by Antibody Gene Transfer. Viruses, 6(2):428-447, Feb 2014. PubMed ID: 24473340. Show all entries for this paper.

Displaying record number 1370

Download this epitope record as JSON.

MAb ID	2G12 (c2G12)
HXB2 Location	Env	Env Epitope Map
Author Location	gp120
Research Contact	Herman Katinger, Inst. Appl. Microbiol. or Polymun Scientific Inc., Vienna, Austria,
Epitope	(Discontinuous epitope)
Subtype	AD
Ab Type	gp120 carbohydrates at glycosylation residues in C2, C3, C4, and V4, gp120 V3 // V3 glycan (V3g)
Neutralizing	L P View neutralization details
Contacts and Features	View contacts and features
Species (Isotype)	human(IgG1κ)
Patient
Immunogen	HIV-1 infection
Keywords	acute/early infection, ADCC, anti-idiotype, antibody binding site, antibody gene transfer, antibody generation, antibody interactions, antibody lineage, antibody polyreactivity, antibody sequence, assay or method development, autoantibody or autoimmunity, autologous responses, binding affinity, brain/CSF, broad neutralizer, cell-line isolated antibody, co-receptor, complement, computational epitope prediction, dendritic cells, drug resistance, dynamics, early treatment, elite controllers, enhancing activity, escape, genital and mucosal immunity, glycosylation, HAART, ART, immunoprophylaxis, immunotherapy, isotype switch, kinetics, memory cells, mimics, mimotopes, mother-to-infant transmission, neutralization, NK cells, polyclonal antibodies, rate of progression, responses in children, review, SIV, structure, subtype comparisons, supervised treatment interruptions (STI), therapeutic vaccine, vaccine antigen design, vaccine-induced immune responses, variant cross-reactivity, viral fitness and reversion

Notes

Showing 535 of 535 notes.

2G12: Analyses of all PDB HIV1-Env trimer (prefusion, closed) structures fulfilling certain parameters of resolution were performed to classify them on the basis of (a) antibody class which was informed by parental B cells as well as structural recognition, and (b) Env residues defining recognized HIV epitopes. Structural features of the 206 HIV epitope and bNAb paratopes were correlated with functional properties of the breadth and potency of neutralization against a 208-strain panel. bNAbs with >25% breadth of neutralization belonged to 20 classes of antibody with a large number of protruding loops and somatic hypermutation (SHM). HIV epitopes recognized placed the bNAbs into 6 categories (viz. V1V2, Glycan-V3, CD4-binding site, Silent face center, Fusion peptide and Subunit Interface). The epitopes contained high numbers of independent sequence segments and glycosylated surface area. 2G12-Env formed a distinct group within the Glycan-V3 category, Class 2G12 due to its unique V_H domain structure. Data for 2G12 complexed to BG505 DS-SOSIP trimer and VRC03 as a cryo-EM electron-density map was solved and deposited as EMD-8981. 2G12 epitope residues on Env were defined as residue 411 and glycans N295, N332, N339, and N392 from the cryo-EM reconstruction. Chuang2019 (antibody binding site, antibody interactions, neutralization, binding affinity, antibody sequence, structure, antibody lineage, broad neutralizer)
2G12: Rabbits were immunized with a DNA vaccine encoding JR-CSF gp120. Five sera with potent autologous neutralizing activity were selected and compared with a human neutralizing plasma (Z23) and monoclonal antibodies targeting various regions of gp120 (VRC01, b12, b6, F425, 2F5, 2G12, and X5). The rabbit sera contained different neutralizing activities dependent on C3 and V5, C3 and V4, or V4 regions of the glycan-rich outer domain of gp120. All sera showed enhanced neutralizing activity toward an Env variant that lacked a glycosylation site in V4. The JR-CSF gp120 epitopes recognized by the sera were distinct from those of the mAbs. The activity of one serum required specific glycans that are also important for 2G12 neutralization, and this serum blocked the binding of 2G12 to gp120. The findings show that different fine specificities can achieve potent neutralization of HIV-1, yet this strong activity does not result in improved breadth. Narayan2013 (neutralization, polyclonal antibodies)
2G12: The study compared well-characterized nAbs (2G12, b12, VRC01, 10E8, 17b) with 4 mAbs derived from a Japanese patient (4E9C, 49G2, 916B2, 917B11), in their neutralization and ADCC activity against viruses of subtypes B and CRF01. CRF01 viruses were less susceptible to neutralization by 2G12 and b12, while VRC01 was highly effective in neutralizing CRF01 viruses. 49G2 showed better neutralization breadth against CRF01 than against B viruses. CRF01_AE viruses from Japan also showed a slightly higher susceptibility to anti-CD4i Ab 4E9C than the subtype B viruses, and to CRF01_AE viruses from Vietnam. Neutralization breadth of other anti-CD4i Abs 17b, 916B2 and 917B11 was low against both subtype B and CRF01_AE viruses. Anti-CD4bs Ab 49G2, which neutralized only 22% of the viruses, showed the broadest coverage of Fc-mediated signaling activity against the same panel of Env clones among the Abs tested. The CRF01_AE viruses from Japan were more susceptible to 49G2-mediated neutralization than the CRF01_AE viruses from Vietnam, but Fc-mediated signaling activity of 49G2was broader and stronger in the CRF01_AE viruses from Vietnam than the CRF01_AE viruses from Japan. Thida2019 (ADCC, neutralization, subtype comparisons)
2G12: The Chinese HIV Reference Laboratory produced 124 pseudoviruses from patients with subype B, BC, and CRF01 infections. These viruses were assigned to tiers based on their neutralization by a panel of patient sera. Their neutralization sensitivities were also measured against a panel of well-characterized mAbs (2F5, b12, 2G12, 4E10, 10E8, VRC01, VRC-CH31, CH01, PG9, PG16, PGT121, PGT126). Nie2020 (assay or method development, neutralization)
2G12: Novel Env pseudoviruses were derived from 22 patients in China infected with subtype CRF01_AE viruses. Neutralization IC50 was determined for 11 bNAbs: VRC01, NIH45-46G54W, 3BNC117, PG9, PG16, 2G12, PGT121, 10-1074, 2F5, 4E10, and 10E8. The CRF01_AE pseudoviruses exhibited different susceptibility to these bNAbs. Overall, 4E10, 10E8, and 3BNC117 neutralized all 22 env-pseudotyped viruses, followed by NIH45-46G54W and VRC01, which neutralized more than 90% of the viruses. 2F5, PG9, and PG16 showed only moderate breadth, while the other three bNAbs neutralized none of these pseudoviruses. Specifically, 10E8, NIH45-46G54Wand 3BNC117 showed the highest efficiency, combining neutralization potency and breadth. Mutations at position 160, 169, 171 were associated with resistance to PG9 and PG16, while loss of a potential glycan at position 332 conferred insensitivity to V3-glycan-targeting bNAbs. These results may help in choosing bNAbs that can be used preferentially for prophylactic or therapeutic approaches in China. Wang2018a (assay or method development, neutralization, subtype comparisons)
2G12: Soluble versions of HIV-1 Env trimers (sgp140 SOSIP.664) stabilized by a gp120-gp41 disulfide bond and a change (I559P) in gp41 have been structurally characterized. Cross-linking/mass spectrometry to evaluate the conformations of functional membrane Env and sgp140 SOSIP.664 has been reported. Differences were detected in the gp120 trimer association domain and C terminus and in the gp41 HR1 region which can guide the improvement of Env glycoprotein preparations and potentially increasing their effectiveness as a vaccine. 2G12 broadly neutralized HIV-1AD8 full-length and cytoplasmic tail-deleted Envs. Castillo-Menendez2019 (vaccine antigen design, structure)
2G12: The authors mutated two conserved tyrosine (Y) residues within the V2 loop of gp120 Y177 and Y173, individually or in combination, by replacing them with either phenylalanine (F) or alanine (A) in a clade B, tier 1B HIV-1 Env protein (BaL), and in a number of tier 2 HIV-1 Envs from different clades, namely, BG505 (clade A), JR-FL and JR-CSF (clade B), and CM244 (clade E). A consistent hierarchy of neutralization sensitivity was seen among the mutants, with a greater impact of Y177 over Y173 single mutations, of double over single mutations, and of A over F substitutions. The double-alanine mutation in mutant HIV-1 BaL, Y173A Y177A, increased sensitivity to all the weakly neutralizing MAbs tested and even rendered the virus sensitive to non-neutralizing antibodies against the CD4 binding site, such as F105, 654-30D, and b13. When tested against bNAbs instead, there was a trend to decrease neutralization sensitivity compared to WT, with the exception of N6, PGT151, 10E8, and 2G12, for which there was no change, and of 2F5 and 4E10, which were more effective against the mutant compared to the WT. Guzzo2018 (antibody binding site, binding affinity)
2G12: Without SOSIP changes, cleaved Env trimers disintegrate into their gp120 and gp41-ectodomain (gp41_ECTO) components. This study demonstrates that the gp41_ECTO component is the primary source of this Env metastability and that replacing wild-type gp41_ECTO with BG505 gp41_ECTO of the uncleaved prefusion-optimized design is a general and effective strategy for trimer stabilization. A panel of 11 bNAbs, including the N332 supersite recognized by PGT121, PGT128, PGT135, and 2G12, was used to assess conserved neutralizing epitopes on the trimer surface, and the main result was that the substitution was found to significantly improve trimer binding to bNAbs VRC01, PGT151, and 35O22, with P values (paired t test) of 0.0229, 0.0269, and 0.0407, respectively. He2018 (antibody interactions, glycosylation, vaccine antigen design)
2G12: To reduce local V2 flexibility and improve the binding of V2-dependent bNAbs and germline precursor bNAbs, the authors designed BG505 SOSIP.664 trimer variants whose V1 and V2 domains were stabilized by introducing disulfide bonds either within the V2 loop or between the V1 and V2 loops. The resulting SOSIP trimer variants — E153C/K178C, E153C/K178C/G152E and I184C/E190C — have improved reactivity with V2 bNAbs and their inferred germline precursors and are more sensitive to neutralization by V2 bNAbs. Compared with BG505 SOSIP.664, the E153C/R178C V1-V2 disulfide mutant bound the VRC01, PGT151, and 2G12 slightly less well and the G152E compensatory mutation improved VRC01, PGT151, and 2G12 binding. However, sensitivity to antibodies 2G12 and PGT151 was not affected for either mutant virus E153C/K178C/G152E and I184C/E190C. deTaeye2019 (antibody interactions, variant cross-reactivity, binding affinity, structure, broad neutralizer)
2G12: This study looks at the role of somatic mutations within antibody variable and framework regions (FWR) in bNAbs and how these mutations alter thermostability and neutralization as the Ab lineage reaches maturation. The emergence and selection of different mutations in the complementarity-determining and framework regions are necessary to maintain a balance between antibody function and stability. The study shows that all major classes of bnAbs (DH2070, CH103, CH235 etc.) have lower thermostability than their corresponding inferred UCA antibodies. Henderson2019 (neutralization, antibody lineage, broad neutralizer)
2G12: Two HIV-1-infected individuals, VC10014 and VC20013, were monitored from early infection until well after they had developed broadly neutralizing activity. The bNAb activity developed about 1 year after infection and mapped to a single epitope in both subjects. Isolates from each subject, taken at five different time points, were tested against monoclonal bNAbs: VRC01, B12, 2G12, PG9, PG16, 4E10, and 2F5. In subject VC10014, the bNAb activity developed around 1 year postinfection and targeted an epitope that overlaps the CD4-BS and is similar to (but distinct from) bNAb HJ16. In the case of VC20013, the bNAb activity targeted a novel epitope in the MPER that is critically dependent on residue 677 (mutation K677N). Sather2014 (neutralization, broad neutralizer)
2G12: This study demonstrated that bNAb signatures can be utilized to engineer HIV-1 Env vaccine immunogens eliciting Ab responses with greater neutralization breadth. Data from four large virus panels were used to comprehensively map viral signatures associated with bNAb sensitivity, hypervariable region characteristics, and clade effects. The bNAb signatures defined for the V2 epitope region were then employed to inform immunogen design in a proof-of-concept exploration of signature-based epitope targeted (SET) vaccines. V2 bNAb signature-guided mutations were introduced into Env 459C to create a trivalent vaccine which resulted in increased breadth of NAb responses compared with Env 459C alone. Bricault2019 (antibody binding site, vaccine antigen design, computational epitope prediction, broad neutralizer)
2G12: The influence of a V2 State 2/3-stabilizing Env mutation, L193A, on ADCC responses mediated by sera from HIV-1-infected individuals was evaluated. Conformations spontaneously sampled by the Env trimer at the surface of infected cells had a significant impact on ADCC. 2G12 was used as a conformation-independent antibody. Prevost2018 (ADCC)
2G12: Polyreactive properties of natural and artificially engineered HIV-1 bNAbs were studied, with almost 60% of the tested HIV-1 bNAbs (including this one) exhibiting low to high polyreactivity in different immunoassays. A previously unappreciated polyreactive binding for PGT121, PGT128, NIH45-46W, m2, and m7 was reported. Binding affinity, thermodynamic, and molecular dynamics analyses revealed that the co-emergence of enhanced neutralizing capacities and polyreactivity was due to an intrinsic conformational flexibility of the antigen-binding sites of bNAbs, allowing a better accommodation of divergent HIV-1 Env variants. Prigent2018 (antibody polyreactivity)
2G12: A systems glycobiology approach was applied to reverse engineer the relationship between bNAb binding and glycan effects on Env proteins. Glycan occupancy was interrogated across every potential N-glycan site in 94 recombinant gp120 antigens. Using a Bayesian machine learning algorithm, bNAb-specific glycan footprints were identified and used to design antigens that selectively alter bNAb antigenicity. The novel synthesized antigens uccessfully bound to target bNAbs with enhanced and selective antigenicity. Yu2018 (glycosylation, vaccine antigen design)
2G12: A panel of bnAbs were studied to assess ongoing adaptation of the HIV-1 species to the humoral immunity of the human population. Resistance to neutralization is increasing over time, but concerns only the external glycoprotein gp120, not the MPER, suggesting a high selective pressure on gp120. Almost all the identified major neutralization epitopes of gp120 are affected by this antigenic drift, suggesting that gp120 as a whole has progressively evolved in less than 3 decades. Bouvin-Pley2014 (neutralization)
2G12: The first cryo-EM structure of a cross-linked vaccine antigen was solved. The 4.2 Å structure of HIV-1 BG505 SOSIP soluble recombinant Env in complex with a bNAb PGV04 Fab fragment revealed how cross-linking affects key properties of the trimer. SOSIP and GLA-SOSIP trimers were compared for antigenicity by ELISA, using a large panel of mAbs previously determined to react with BG505 Env. Non-NAbs globally lost reactivity (7-fold median loss of binding), likely because of covalent stabilization of the cross-linked ‘closed’ form of the GLA-SOSIP trimer that binds non-NAbs weakly or not at all. V3-specific non-NAbs showed 2.1–3.3-fold reduced binding. Three autologous rabbit monoclonal NAbs to the N241/N289 ‘glycan-hole’ surface, showed a median ˜1.5-fold reduction in binding. V3 non-NAb 4025 showed residual binding to the GLA-SOSIP trimer. By contrast, bNAbs like 2G12 broadly retained reactivity significantly better than non-NAbs, with exception of PGT145 (3.3-5.3 fold loss of binding in ELISA and SPR). Schiffner2018 (vaccine antigen design, binding affinity, structure)
2G12: This study describes the generation of CHO cell lines stably expressing the following vaccine Env Ags: CRF01_AE A244 Env gp120 protein (A244.AE) and 6240 Env gp120 protein (6240.B). The antigenic profiles of the molecules were assessed with a panel of well-characterized mAbs recognizing critical epitopes and glycosylation analysis confirming previously identified sites and revealing unknown sites at non-consensus motifs. A244.AE gp120 showed low level of binding to 2G12 in ELISA EC50 and Surface Plasmon Resonance (SPR) assays. 6240.B gp120 exhibited binding to 2G12. Wen2018 (glycosylation, vaccine antigen design)
2G12: Assays of poly- and autoreactivity demonstrated that broadly neutralizing NAbs are significantly more poly- and autoreactive than non-neutralizing NAbs. 2G12 is neither autoreactive nor polyreactive. Liu2015a (autoantibody or autoimmunity, antibody polyreactivity)
2G12: A panel of 14 pseudoviruses of subtype CRF01_AE was developed to assess the neutralization of several neutralizing antibodies (b12, PG9, PG16, 4E10, 10E8, 2F5, PGT121, PGT126, 2G12). Neutralization was assessed in both TZM-bl and A3R5 cell-based assays. Most viruses were more susceptible to mAb-neutralization in A3R5 than in the TZM-bl cell-based assay. The increased neutralization sensitivity observed in the A3R5 assay was not linked to the year of virus transmission or to the stages of infection, but chronic viruses from the years 1990-92 were more sensitive to neutralization than the more current viruses, in both assays. Chenine2018 (assay or method development, neutralization, subtype comparisons)
2G12: The immunologic effects of mutations in the Env cytoplasmic tail (CT) that included increased surface expression were explored using a vaccinia prime/protein boost protocol in mice. After vaccinia primes, CT- modified Envs induced up to 7-fold higher gp120-specific IgG, and after gp120 protein boosts, they elicited up to 16-fold greater Tier-1 HIV-1 neutralizing antibody titers. Hogan2018 (vaccine antigen design)
2G12: SOSIP.664 trimer was modified at V3 positions 306 and 308 by Leucine substitution to create hydrophobic interactions with the tryptophan residue at position 316 and the V1V2 domain. These modifications stabilized the resulting SOSIP.v5.2 S306L R308L trimers. In vivo, the induction of V3 non-NAbs was significantly reduced compared with the SOSIP.v5.2 trimers. S306L plus R308L paired substitutions had no effect on the trimer reactivity of 2G12. deTaeye2018 (broad neutralizer)
2G12: Repetitive immunization of macaques over 3 years with an Env expressing V3-high mannose glycan, CON-S gp140CFI, elicited plasma antibodies neturalizing HIV-1 expressing high mannose glycans only. NAb DH501 was isolated and found to possess a structure where 3 V_H chain CDRs formed a cavity into which the HIV-1 Env V3-glycan could insert. Rhesus DH501 possessed characteristics of V3-glycan bNAb precursors but its binding to M.CON-S gp140CFI was blocked 70% by 2G12. Saunders2017 (vaccine-induced immune responses, structure)
2G12: Nanodiscs (discoidal lipid bilayer particles of 10-17 nm surrounded by membrane scaffold protein) were used to incorporate Env complexes for the purpose of vaccine platform generation. The Env-NDs (Env-NDs) were characterized for antigenicity and stability by non-NAbs and NAbs. Most NAb epitopes in gp41 MPER and in the gp120:gp41 interface were well exposed while non-NAb cell surface epitopes were generally masked. Anti-gp120 glycan NAb 2G12, had a Kd of 10.16 nM and bound the Env-ND well. Witt2017 (vaccine antigen design, binding affinity)
2G12: The DS-SOSIP.4mut is a soluble, closed pre-fusion-state HIV-1 Env trimer that has improved stability and immunogenicity. It has 4 specific alterations at M154, M300, M302 and L320. 2G12 recognizes this trimer antigenically. Chuang2017 (antibody interactions)
2G12: Three strategies were applied to perturb the structure of Env in order to make the protein more susceptible to neutralization: exposure to cold, Env-activating ligands, and a chaotropic agent. A panel of mAbs (E51, 48d, 17b, 3BNC176, 19b, 447-52D, 39F, b12, b6, PG16, PGT145, PGT126, 35O22, F240, 10E8, 7b2, 2G12) was used to test the neutralization resistance of a panel of subtype B and C pseudoviruses with and without these agents. Both cold and CD4 mimicking agents (CD4Ms) increased the sensitivity of some viruses. The chaotropic agent urea had little effect by itself, but could enhance the effects of cold or CD4Ms. Thus Env destabilizing agents can make Env more susceptible to neutralization and may hold promise as priming vaccine antigens. Johnson2017 (vaccine antigen design)
2G12: Man₉-V3, a synthetic minimal immunogen designed to reflect the HIV-1 native Env V3-glycan bNAb epitope, binds memory B cells and V3-glycan bNAbs as well as germline bNAbs. Man₉-V3 was used to isolate a bNAb from an HIV-1+ subject and also induce V3-glycan-targeting antibodies in rhesus macaques. Using the crystal structure of PGT128-gp120 Env OD (outer domain), Man₉-V3 glycopeptide was synthesized based on Clade B JRFL with deletion of residues 305-320, retention of P321 and stabilization of disulfide bridge C296-C331. High mannose-glycans presented on Man₉-V3 were appropriately spaced for binding to 2G12. Alam2017 (antibody binding site)
2G12: Env from of a highly neutralization-resistant isolate, CH120.6, was shown to be very stable and conformationally-homogeneous. Its gp140 trimer retains many antigenic properties of the intact Env, while its monomeric gp120 exposes more epitopes. Thus trimer organization and stability are important determinants for occluding epitopes and conferring resistance to antibodies. Among a panel of 21 mAbs, CH120.6 was resistant to neutralization by all non-neutralizing and strain-specific mAbs, regardless of the location of their epitopes. It was weakly neutralized by several broadly-neutralizing mAbs (VRC01, NIH45-46, 12A12, PG9, PG16, PGT128, 4E10, and 10E8), and well neutralized by only 2 (PGT145 and 10-1074). Cai2017 (neutralization)
2G12: Mice twice-primed with DNA plasmids encoding HIV-1 gp120 and gag and given a double boost with HIV-1 virus-like particles (VLPs) i.e. DDVV immunization, elicited Env-specific antibody responses as well as Env- and Gag-specific CTL responses. In vivo electroporation (EP) was used to increase breadth and potency of response. Human anti-gp120 2G12 was used to prove that the VLP spike included the broad neutralization epitope recognized by it. Huang2017a (therapeutic vaccine, variant cross-reactivity)
2G12: A panel of mAbs (2G12, VRC01, HJ16, 2F5, 4E10, 35O22, PG9, PGT121, PGT126, 10-1074) was tested to compare their efficacy in cell-free versus cell-cell transmission. Almost all bNAbs (with the exception of anti-CD4 mAb Leu3a) blocked cell-free infection with greater potency than cell-cell infection, and showed greater potency in neutralization of cell-free viruses. The lower effectiveness on neutralization was particularly pronounced for transmitted/founder viruses, and less pronounced for chronic and lab-adapted viruses. The study highlights that the ability of an antibody to inhibit cell-cell transmission may be an important consideration in the development of Abs for prophylaxis. Li2017 (immunoprophylaxis, neutralization)
2G12: Compared to patient-derived mAbs, vaccine-elicited mAbs are often less able to neutralize the virus, due to a less-effective angle of approach to the Env spike. This study engineered an immunogen consisting of the gp120 core in complex with a CD4bs mAb, 17b. Rabbits immunized with this antigen displayed earlier affinity maturation and better virus neutralization compared to those immunized with the gp120 core alone. VRC01 and 2G12 bound to the the 17b-gp120 complex more avidly than to the gp120 core alone. Chen2016b (antibody binding site, vaccine antigen design, vaccine-induced immune responses, structure)
2G12: The amino acid at gp120 position 375 is embedded in the Phe43 cavity, which affects susceptibility to ADCC. Most M-group strains of HIV-1 have serine at position 375, but CRF01 typically has histidine, which is a bulky residue. MAbs 2G12 and 10E8 were not affected by changes in residue 375, while recognition by CD4i mAbs 17b and A32 was increased by mutations of residue 375 to histidine or tryptophan. Participants in the AIDSVAX vaccine trial were infected by CRF01, and a significant part of the efficacy of this vaccine rested on ADCC responses. The ADCC response of MAbs derived from AIDSVAX participants (CH29, CH38, CH40, CH51, CH52, CH54, CH77, CH80, CH81, CH89, CH91, CH94) was dependent on the presence of 375H and greatly decreased by the presence of 375S. Prevost2017 (ADCC, vaccine-induced immune responses)
2G12: This review focuses on the potential role of HIV-1-specific NAbs in preventing HIV-1 infection. Several NAbs have provided protection from infection in SHIV challenge studies in primates: b12, VRC01, VRC07-523LS, 3BNC117, PG9, PGT121, PGT126, 10-1074, 2G12, 4E10, 2F5, 10E8. Pegu2017 (immunoprophylaxis, review)
2G12: Prevalence, breadth, and potency of NAb responses in 98 CRF07_BC-infected individuals using a multi-subtype panel of 30 tier 2-3 Env-pseudotyped viruses were identified and the neutralization pattern of CRF07_BC-infected people was compared with that of subtype B'-infected individuals in China. 18% of 98 plasma samples neutralized >80% of viruses, and 53% neutralized >50%, suggesting the presence of broadly NAbs. CRF07_BC-infected individuals generated higher but less broad neutralization titers against intra-subtype viruses than subtype B'-infected individuals with longer infection length, indicating the transition from narrow autologous to broad heterologous neutralization over time. Neutralization activity of the top six plasmas from each cohort was attributable to the IgG fraction, and half of them developed CD4 binding site antibody reactivity. VRC01 and 2G12 were used as controls. Hu2017 (broad neutralizer)
2G12: This study investigated Ab binding abilities of saccharide ligands and the effects of the inner water molecules of ligand–Ab complexes. 2G12 complexes with saccharide ligands were studied by modeling to estimate how inner water molecules of the protein affect the dynamics of the complexes as well as the ligand–Ab interaction. This indicates that D -fructose’s strong affinity to the Ab was partly due to the good retentiveness of solvent water molecules of the ligand and its stability of the ligand’s conformation and relative position in the active site. Ueno-Noto2016 (antibody binding site, antibody interactions)
2G12: The results confirm that Nef and Vpu protect HIV-1-infected cells from ADCC, but also show that not all classes of antibody can mediate ADCC. Anti-cluster-A antibodies are able to mediate potent ADCC responses, whereas anti-coreceptor binding site antibodies are not. Position 69 in gp120 is important for antibody-mediated cellular toxicity by anti-cluster-A antibodies. The angle of approach of a given class of antibodies could impact its capacity to mediate ADCC. MAb 2G12 was used as a CD4-independent outer-domain-recognizing antibody to show that more Env is present on the cell surface in cells infected with Vpu-deleted HIV. Ding2015 (ADCC)
2G12: The ability of neutralizing and nonneutralizing mAbs to block infection in models of mucosal transmission was tested. Neutralization potency did not fully predict activity in mucosal tissue. CD4bs-specific bNAbs, in particular VRC01, blocked HIV-1 infection across all cellular and tissue models. MPER (2F5) and outer domain glycan (2G12) bNAbs were also efficient in preventing infection of mucosal tissues, while bNAbs targeting V1-V2 glycans (PG9 and PG16) were more variable. Non-nAbs alone and in combinations, were poorly protective against mucosal infection. The protection provided by specific bNAbs demonstrates their potential over that of nonneutralizing antibodies for preventing mucosal entry. 2G12 was selected to represent mAbs of the outer domain glycan class. Cheeseman2017 (genital and mucosal immunity, immunoprophylaxis)
2G12: This study investigated the ability of native, membrane-expressed JR-FL Env trimers to elicit NAbs. Rabbits were immunized with virus-like particles (VLPs) expressing trimers (trimer VLP sera) and DNA expressing native Env trimer, followed by a protein boost (DNA trimer sera). N197 glycan- and residue 230- removal conferred sensitivity to Trimer VLP sera and DNA trimer sera respectively, showing for the first time that strain-specific holes in the "glycan fence" can allow the development of tier 2 NAbs to native spikes. All 3 sera neutralized via quaternary epitopes and exploited natural gaps in the glycan defenses of the second conserved region of JR-FL gp120. Fig S7 showed that gp120 monomer and gp140F trimer both interfered with mAb 2G12 neutralization, but 2G12 was unable to inhibit CD4bs NAb binding. Crooks2015 (glycosylation, neutralization)
2G12: Nedd8 activation enzyme inhibitor, MLN4924, partially blocks Vpu activity through CD4 downregulation. Host antiviral factor BST2, however, is not inhibited and so reversal of Vpu activity is partial, exposing CD4-induced eptiopes that recruit ADCC-mediated host defense. Ab 2G12 which recognizes a CD4-independent epitope was used to show that even under best conditions, MLN4924 only minimally increases the binding of 2G12 to Env. Tokarev2015 (ADCC)
2G12: New antibodies were isolated from 3 patients: Donor 14 (PDGM11, PGDM12, PGDM13, PGDM14), Donor 82 (PGDM21), and Donor 26 (PGDM31). These bnAbs bound both the GDIR peptide (Env 324-327) and the high-mannose patch glycans, enabling broad reactivity. N332 glycan was absolutely required for neutralization, while N301 glycan modestly affected neutralization. Removing N156 and N301 glycans together while retaining N332 glycan abrogated neutralization for PGDM12 and PGDM21. Neutralization by PGDM11-14 bnAbs depended on R327A and H330A substitutions and neutralization by PGDM21 depended on D325A and H330A substitutions. G324A mutation resulted in slight loss of neutralization for both antibody families. In comparison, 2G12 and PGT135 did not show any dependence on residues in the 324GDIR327 region for neutralization activity, although PGT135 did show dependence on H330. Sok2016 (antibody binding site, glycosylation)
2G12: Env residue N197 on the BG505-SOSIP trimer was mutated to test the effect of its glycosylation on the binding kinetics of CD4BS and other mAbs. Removal of the glycan had little effect on the overall structure of the molecule. Its removal resulted in increased binding of CD4 and CD4BS antibodies (VRC01, VRC03, V3-3074), but little effect on bNAbs targeting other epitopes (PG9, PG16, PGT145, 17b, A32, 2G12, PGT121, PGT126). Two CD4BS-binding antibodies tested (b12, F105) had insufficient breadth to bind the BG505-SOSIP trimer. Removal of the N197 glycan may allow for the development of better SOSIP immunogens, particularly to elicit CD4BS-specific Abs. Liang2016 (glycosylation, vaccine antigen design)
2G12: This study produced Env SOSIP trimers for clades A (strain BG505), B (strain JR-FL), and G (strain X1193). Based on simulations, the MAb-trimer structures of all MAbs tested needed to accommodate at least one glycan, including both antibodies known to require specific glycans (PG9, PGT121, PGT135, 8ANC195, 35O22) and those that bind the CD4-binding site (b12, CH103, HJ16, VRC01, VRC13). A subset of monoclonal antibodies bound to glycan arrays assayed on glass slides (VRC26.09, PGT121, 2G12, PGT128, VRC13, PGT151, 35O22), while most of the antibodies did not have affinity for oligosaccharide in the context of a glycan array (PG9, PGT145, PGDM1400, PGT135, b12, CH103, HJ16, VRC16, VRC01, VRC-PG04, VRC-CH31, VRC-PG20, 3BNC60, 12A12, VRC18b, VRC23, VRC27, 1B2530, 8ANC131, 8ANC134, 8ANC195). Stewart-Jones2016 (antibody binding site, glycosylation, structure)
2G12: This study assessed the ADCC activity of antibodies of varied binding types, including CD4bs (b6, b12, VRC01, PGV04, 3BNC117), V2 (PG9, PG16), V3 (PGT126, PGT121, 10-1074), oligomannose (2G12), MPER (2F5, 4E10, 10E8), CD4i (17b, X5), C1/C5 (A32, C11), cluster I (240D, F240), and cluster II (98-6, 126-7). ADCC activity was correlated with binding to Env on the surfaces of virus-infected cells. ADCC was correlated with neutralization, but not always for lab-adapted viruses such as HIV-1 NLA-3. vonBredow2016 (ADCC)
2G12: This review summarizes representative anti-HIV MAbs of the first generation (2G12, b12, 2F5, 4E10) and second generation (PG9, PG16, PGT145, VRC26.09, PGDM1400, PGT121, PGT124, PGT128, PGT135, 10-1074, VRC01, 3BNC117, CH103, PGT151, 35O22, 8ANC195, 10E8). Structures, epitopes, VDJ usage, CDR usage, and degree of somatic hypermutation are compared among these antibodies. The use of SOSIP trimers as immunogens to elicit B-cell responses is discussed. Burton2016 (review, structure)
2G12: Two stable homogenous gp140 Env trimer spikes, Clade A 92UG037.8 Env and Clade C C97ZA012 Env, were identified. 293T cells stably transfected with either presented fully functional surface timers, 50% of which were uncleaved. A panel of neutralizing and non-neutralizing Abs were tested for binding to the trimers. Glycan Ab 2G12 bound cell surface gp160 weakly and strongly bound it without its C-terminal (gp160ΔCT), whether in the presence of sCD4 or not. It was unable to neutralize the 92UG037.8 HIV-1 isolate. Chen2015 (neutralization, binding affinity)
2G12: PGT145 was used to positively isolate a subtype B Env trimer immunogen, B41 SOSIP.664-D7324, that exists in two conformations, closed and partially open. bNAbs tested against the trimer were able to neutralize the B41 pseudovirus with a wide range of potencies. All tested non-NAbs did not neutralize B41 (IC₅₀ >50µg/ml). OD glycan bNAb, 2G12, neutralized and bound B41 pseudovirus and trimer. Pugach2015
2G12: A comprehensive antigenic map of the cleaved trimer BG505 SOSIP.664 was made by bNAb cross-competition. Epitope clusters at the CD4bs, quaternary V1/V2 glycan, N332-oligomannose patch and new gp120-gp41 interface and their interactions were delineated. Epitope overlap, proximal steric inhibition, allosteric inhibition or reorientation of glycans were seen in Ab cross-competition. Thus bNAb binding to trimers can affect surfaces beyond their epitopes. 2G12 non-reciprocally out-competed PGT135 and PGT136, all N332-outer domain (OD) glycan oligomannose patch bNAbs. Derking2015 (antibody interactions, neutralization, binding affinity, structure)
2G12: Two clade C recombinant Env glycoprotein trimers, DU422 and ZM197M, with native-like structural and antigenic properties involving epitopes for all known classes of bNAbs, were produced and characterized. These Clade C trimers (10-15% of which are in a partially open form) were more like B41 Clade B trimers which have 50-75% trimers in the partially open configuration than like B505 Clade B trimers, almost 100% in the closed, prefusion state. The Clade C trimers are reactive with bNAb 2G12, which was used to purify antigenically high quality, native-like trimers. OD-glycan binding 2G12 however, was not able to neutralize the equivalent pseudotyped viruses for either trimer. Julien2015 (assay or method development, structure)
2G12: Env trimer BG505 SOSIP.664 as well as the clade B trimer B41 SOSIP.664 were stabilized using a bifunctional aldehyde (glutaraldehye, GLA) or a heterobifunctional cross-linker, EDC/NHS with modest effects on antigenicity and barely any on biochemistry or structural morphology. ELISA, DSC and SPR were used to test recognition of the trimers by bNAbs, which was preserved and by weakly NAbs or non-NAbs, which was reduced. Cross-linking partially preserves quaternary morphology so that affinity chromatography by positive selection using quaternary epitope-specific bNAabs, and negative selection using non-NAbs, enriched antigenic characteristics of the trimers. Mannose patch-specific gp120-binding bNAb, 2G12, was conformationally insensitive to mild denaturation during ELISA and bound timers. Schiffner2016 (assay or method development, binding affinity, structure)
2G12: The native-like, engineered trimer BG505 SOSIP.664 induced potent NAbs against conformational epitopes of neutralization-resistant Tier-2 viruses in rabbits and macaques, but induced cross-reactive NAbs against linear V3 epitopes of neutralization-sensitive Tier-1 viruses. A different trimer, B41 SOSIP.664 also induced strong autologous Tier-2 NAb responses in rabbits. Sera from only 2/20 BG505 SOSIP.664-D7324 trimer-immunized rabbits were capable of inhibiting N332 glycan-dependent 2G12 binding to outer domain glycans. Sanders2015 (antibody generation, neutralization, binding affinity, polyclonal antibodies)
2G12: A new trimeric immunogen, BG505 SOSIP.664 gp140, was developed that bound and activated most known neutralizing antibodies but generally did not bind antibodies lacking neuralizing activity. This highly stable immunogen mimics the Env spike of subtype A transmitted/founder (T/F) HIV-1 strain, BG505. Anti-OD glycan bNAb 2G12 neutralized BG505.T332N, the pseudoviral equivalent of the immunogen BG505 SOSIP.664 gp140, and was shown to recognize and bind the immunogen too. Sanders2013 (assay or method development, neutralization, binding affinity)
2G12: This review discusses the application of bNAbs for HIV treatment and eradication, focusing on bnAbs that target key epitopes, specifically: 2G12, 2F5, 4E10, VRC01, 3BNC117, PGT121, VRC26.08, VRC26.09, PGDM1400, and 10-1074. Antibodies 2G12, 2F5, and 4E10 were among the first bnAbs available for clinical testing, and a cocktail of these 3 Abs was assessed in human trials. Stephenson2016 (immunotherapy, review)
2G12: This study described a natural interaction between Abs and mucin protein, especially, MUC16 that is enhanced in chronic HIV infection. Agalactosylated (G0) Abs demonstrated the highest binding to MUC16. Binding of Abs to epithelial cells was diminished following MUC16 knockdown, and the MUC16 N-linked glycans were critical for binding.These point to a novel opportunity to enrich Abs at mucosal sites by targeting Abs to MUC16 through changes in Fc glycosylation, potentially blocking viral movement. In 2G12 differential G0 content was linked to MUC16 binding supporting a role for G0 glycosylation in preferential MUC16 binding, independent of antigen specificity (Fig: S4). Gunn2016 (antibody interactions, glycosylation)
2G12: A mathematical model was developed to predict the Ab concentration at which antibody escape variants outcompete their ancestors, and this concentration was termed the mutant selection window (MSW). The MSW was determined experimentally for 12 pairings of diverse HIV strains against 7 bnAbs (b12, 2G12, PG9, PG16, PGT121, PGT128, 2F5). The neutralization of 2G12 was assayed against JRFL-N332S (resistant strain) and JRFL (sensitive strain). Magnus2016 (neutralization, escape)
2G12: The study detailed binding kinetics of the interaction between BG505 SOSIP.664 trimer or its variants (gp120 monomer; first study of disulfide-stabilized variant gp120-gp41_ECTO protomer) and several mAbs, both neutralizing (VRC01, PGV04, PG9, PG16, PGT121, PGT122, PGT123, PGT145, PGT151, 2G12) and non-neutralizing (b6, b12, 14e, 19b, F240). Glycan-binding 2G12 bound similarly to monomer and trimer and marginally better to protomer. Yasmeen2014 (antibody binding site, assay or method development)
2G12: 2G12 was expressed in transgenic rice endosperm to evaluate the potential of rice seeds as a vehicle for inexpensive microbicide production. Although the heavy chain was predominantly aglycosylated, the heavy and light chains assembled into functional antibodies with more potent HIV-neutralizing activity than other plant-derived forms of 2G12 bearing typical high-mannose or plant complex-type glycans. Assembled antibody accumulated predominantly in protein storage vacuoles but also induced the formation of novel, spherical storage compartments surrounded by ribosomes indicating that they originated from the endoplasmic reticulum. Vamvaka2016
2G12: Neutralization breadth in 157 antiretroviral-naive individuals infected for less than 1 year post-infection was studied and compared to a cohort of 170 untreated chronic patients. A range of neutralizing activities was observed with a panel of six recombinant viruses from five different subtypes. Some sera were broadly reactive, predominantly targeting envelope epitopes within the V2 glycan-dependent region. The Env neutralization breadth was positively associated with time post infection. 2G12 has been used as a control in detection of glycan-dependent HIV-1 neutralizing sera. Sanchez-Merino2016 (neutralization, acute/early infection)
2G12: Ten mAbs were isolated from a vertically-infected infant BF520 at 15 months of age. Ab BF520.1 neutralized pseudoviruses from clades A, B and C with a breadth of 58%, putting it in the same range as second-generation bNAbs derived from adults, but its potency was lower. BF520.1 was shown to target the base of the V3 loop at the N332 supersite. Outer domain glycan-binding, first generation mAb, 2G12 when compared had a geometric mean of IC₅₀=2.43 µg/ml for 2/12 viruses it neutralized at a potency of 17%. The infant-derived antibodies had a lower rate of somatic hypermutation (SHM) and no indels compared to adult-derived anti-V3 mAbs. This study shows that bnAbs can develop without SHM or prolonged affinity maturation. Simonich2016 (neutralization, structure)
2G12: The neutralization of 14 bnAbs was assayed against a global panel of 12 or 17 Env pseudoviruses. From IC₅₀, IC₈₀, IC₉₀, and IC₉₉ values, the slope of the dose-response curve was calculated. Each class of Ab had a fairly consistent slope. Neutralization breadth was strongly correlated with slope. An IIP (Instantaneous Inhibitory Potential) value was calculated, based on both the slope and IC50, and this value may be predictive of clinical efficacy. 2G12, a high mannose (HM) cluster bnAb belonged to a group with slopes ˜1. Webb2015 (neutralization)
2G12: The study's goal was to produce modified SOSIP trimers that would reduce the exposure - and, by inference, the immunogenicity - of non-NAb epitopes such as V3. The binding of several modified SOSIP trimers was compared among 12 neutralizing (PG9, PG16, PGT145, PGT121, PGT126, 2G12, PGT135, VRC01, CH103, CD4, IgG2, PGT151, 35O22) and 3 non-neutralizing antibodies (14e, 19b, b6). The V3 non-NAbs 447-52D, 39F, 14e, and 19b bound less well to all A316W variant trimers compared to wild-type trimers. Mice and rabbits immunized with modified, stabilized SOSIP trimers developed fewer V3 Ab responses than those immunized with native trimers. deTaeye2015 (antibody binding site)
2G12: HIV-1 strains were isolated from 60 patients infected with CRFs 01_AE, 07_BC, and 08_BC. Eight CRF01 strains that produced high-titer Env pseudoviruses were studied further. All were sensitive to neutralization by VRC01, PG9, PG16, and NIH45-46, but insensitive to 2G12. Of the 8 strains, 7 lacked glycans at Env 295 or 332, or both, suggesting that these glycosylation sites play a role in 2G12 binding and neutralization. Chen2016 (neutralization, subtype comparisons)
2G12: A large cross-sectional study of sera from 205 ART-naive patients infected with different HIV clades was tested against a panel of 219 cross-clade Env-pseudotyped viruses. Their neutralization was compared to the neutralization of 10 human bNAbs (10E8, 4E10, VRC01, PG9, PGT145, PGT128, 2F5, CH01, b12, 2G12) tested with a panel of 119 Env-pseudotyped viruses. Results from b12 and 2G12 suggested that these bnAbs may not be as broadly neutralizing as previously thought. 2G12 neutralized 20% of the 199 viruses tested, whereas a previous study had estimated this value at 41%. Hraber2014 (neutralization)
2G12: A flow-cytometry-based assay allowed non-radioactive measurement of ADCC-mediated elimination of HIV-1 gp120 envelope glycoprotein (Env)-coated target cells. This assay relies on staining target and effector cells with different dyes, which allows precise gating and permits the calculation of the number of surviving target cells by normalization to flow-cytometry particles. Richard2014 (ADCC, anti-idiotype, assay or method development)
2G12: This study describes a new level of complexity in antibody recognition of the mixed glycan-protein epitopes of the N332 region of HIV gp120. A combination of three antibody families that target the high-mannose patch can lead to 99% neutralization coverage of a large panel of viruses containing the N332/334 glycan site and up to 66% coverage for viruses that lack the N332/334 glycan site. PGT121, PGT128 and PGT135 families were studied. 2G12 was used as control since its binding is N332-dependent but it is less potent and broad in neutralization, recognizes glycans solely, and has a unique domain-exchanged structure. Sok2014a (antibody interactions, glycosylation)
2G12: Incomplete neutralization may decrease the ability of bnAbs to protect against HIV exposure. In order to determine the extent of non-sigmoidal slopes that plateau at <100% neutralization, a panel of 24 bnMAbs targeting different regions on Env was tested in a quantitative pseudovirus neutralization assay on a panel of 278 viral clones. All bNAbs had some viruses that they neutralized with a plateau <100%, but those targeting the V2 apex and MPER did so more often. All bnMAbs assayed had some viruses for which they had incomplete neutralization and non-sigmoidal neutralization curves. bNAbs were grouped into 3 groups based on their neutralization curves: group 1 antibodies neutralized more than 90% of susceptible viruses to >95% (PGT121-123, PGT125-128, PGT136, PGV04); group 2 was less effective, resulting in neutralization of 60-84% of susceptible viruses to >95% (b12, PGT130-131, PGT135, PGT137, PGT141-143, PGT145, 2G12, PG9); group 3 neutralized only 36-60% of susceptible viruses to >95% (PG16, PGT144, 2F5, 4E10). Among the panel tested, antibodies b12, 2G12, PGT136, and PGT137 had relatively few viruses neutralized with an IC50 <1 ug/ml. McCoy2015 (neutralization)
2G12: The neutralization abilities of Abs were enhanced by bioconjugation with aplaviroc, a small-molecule inhibitor of virus entry into host cells. Diazonium hexafluorophosphate was used. The conjugated Abs blocked HIV-1 entry through two mechanisms: by binding to the virus itself and by blocking the CCR5 receptor on host cells. Chemical modification did not significantly alter the potency and the pharmacokinetics. Improvements in potency over the parent Ab was ∼3-fold for 2G12-aplaviroc against the JR-FL isolate. Gavrilyuk2013 (neutralization)
2G12: Galactosyl ceramide (Galcer), a glycosphingolipid, is a receptor for the HIV-1 Env glycoprotein. This study has mimicked this interaction by using an artificial membrane containing synthetic Galcer and recombinant HIV-1 Env proteins to identify antibodies that would block the HIV-1 Env-Galcer interaction. HIV-1 ALVAC/AIDSVAX vaccinee-derived MAbs specific for the gp120 C1 region blocked Galcer binding of a transmitted/founder HIV-1 Env gp140. The antibody-dependent cellular cytotoxicity-mediating CH38 IgG and its natural IgA isotype were the most potent blocking antibodies.2G12 did not block Env-Galcer binding. Dennison2014 (ADCC, antibody binding site, antibody interactions, glycosylation)
2G12: This review surveyed the Vectored Immuno Prophylaxis (VIP) strategy, which involves passive immunization by viral vector-mediated delivery of genes encoding bnAbs for in vivo expression. Recently published studies in humanized mice and macaques were discussed as well as the pros and cons of VIP towards clinical applications to control HIV endemics. A single injection of AAV8 vector achieved peak Ab production in serum at week 6 and offered moderate protection. 2G12 (˜250 μg/mL) yielded partial protection. Yang2014 (immunoprophylaxis, review, antibody gene transfer)
2G12: The ability of bNAbs to inhibit the HIV cell entry was tested for b12, VRC01,VRC03, PG9, PG16, PGT121, 2F5, 10E8, 2G12. Among them, PGT121, VRC01, and VRC03 potently inhibited HIV entry into CD4+ T cells of infected individuals whose viremia was suppressed by ART. Chun2014 (immunotherapy)
2G12: Pairwise combinations of 6 NAbs (4E10, 2F5, 2G12, b12, PG9, PG16) were tested for neutralization of pseudoviruses and transmitted/founder viruses. Each of the NAbs tested targets a different region of gp120 or gp41. Some pairwise combinations enhanced neutralization synergistically, suggesting that combinations of NAbs may enhance clinical effectiveness. Miglietta2014 (neutralization)
2G12: The study compared various factors affecting the accessibility of epitopes for antibodies targeting the V2 integrin (V2i) region, versus the V3 region. CD4 treament of BaL and JRFL pseudoviruses increased their neutralization sensitivity to V3 MAbs, but not to V2i MAbs. Viruses grown in a glycosidase inhibitor were more sensitive to neutralization by V3, but not V2i, MAbs. Increasing the time of virus-MAb interaction increased virus neutralization by some V2i MAbs and all V3 MAbs. The structural dynamics of V2i and V3 epitopes has important effects in neutralization. Some experiments also included CD4BS antibodies b12, 2G12 and NIH45-46. Upadhyay2014
2G12: Dimeric 2G12 is much more potent than the monomeric form. This study compared monomeric and dimeric 2G12 by examination of crystal structures and electron microscopy. The greater potency and breadth of the dimeric form were attributed to intermolecular domain exchange, flexibility, and the avidity effects of bivalent binding. Wu2013 (structure)
2G12: Cross-group neutralization of HIV-1 isolates from groups M, N, O, and P was tested with diverse patient sera and bNAbs PG9, PG16, 4E10, b12, 2F5, 2G12, VRC01, VRC03, and HJ16. The primary isolates displayed a wide spectrum of sensitivity to neutralization by the human sera, with some cross-group neutralization clearly observed. Among the bNAbs, only PG9 and PG16 showed any cross-group neutralization. The group N prototype strain YBF30 was highly sensitive to neutralization by PG9, and the interaction between their key residues was confirmed by molecular modeling. The conservation of the PG9/PG16 epitope within groups M and N suggests its relevance as a vaccine immunogen. Braibant2013 (neutralization, variant cross-reactivity)
2G12: The binding affinity of 2G12 for sugar molecules associated with glycans was tested through computer modeling. Affinity for D-fructose was greater than for D-mannose. Koyama2014 (binding affinity)
2G12: The structure of 2G12 in association with Env trimer from HIV strain BG505-SOSIP was characterized. The 2G12 epitope overlaps with several other bNAbs that target the N332 supersite of vulnerability. Glycans N295, N392, and N339 are centrally located within the footprint of the antibody, while N448 and N386 are on the periphery. 2G12 may block membrane fusion by inducing steric hindrance upon primary receptor binding, thus abrogating Env's interaction with coreceptors. Murin2014 (structure)
2G12: 2G12 was one of 10 MAbs used to study chronic vs. consensus vs. transmitted/founder (T/F) gp41 Envs for immunogenicity. Consensus Envs were the most potent eliciters of response but could only neutralize tier 1 and some tier 2 viruses. T/F Envs elicited the greatest breadth of NAb response; and chronic Envs elicited the lowest level and narrowest response. This Glycan binding Nab bound well at <10 nM to 3/5 chronic Envs, 4/6 Consensus Envs and 4/7 T/F Envs. Liao2013c (antibody interactions, binding affinity)
2G12: The infectious virion (iVirions) capture index (IVCI) of different Abs have been determined. bnAbs captured higher proportions of iVirions compared to total virus particles (rVirions) indicating the capacity, breadth and selectively of bnAbs to capture iVirions. IVCI was additive with a mixture of Abs, providing proof of concept for vaccine-induced effect of improved capacity. bnAb 2G12 showed significantly high IVCI >1.0, but did not capture HIV subtype B T/F CH040, subtype C CH185.C, or subtype A/E AE.92TH023. Liu2014 (binding affinity)
2G12: Study evaluated 4 gp140 Env protein vaccine immunogens derived from an elite neutralizer donor VC10042, an HIV+ African American male from Vanderbilt cohort. Env immunogens, VC10042.05, VC10042.05RM, VC10042.08 and VC10042.ela, elicited high titers of cross-reactive Abs recognizing V1/V2 regions. All the Env protein except VC10042.ela bound to 2G12, but none of the parental Env were neutralized by 2G12. Carbonetti2014 (elite controllers, vaccine-induced immune responses)
2G12: The effect of low pH and HIV-1 Abs which increased the transcytosis of the virus by 20 fold, has been reported. This enhanced transcytosis was due to the Fc neonatal receptor (FcRn), which facilitates HIV-1's own transmission by usurping Ab responses directed against itself. Both infectious and noninfectious viruses were transcytosed by 2G12. Gupta2013
2G12: This study examined how the conserved gp120-gp41 association site adapts to glycan changes that are linked to neutralization sensitivity, using a DSR mutant virus, K601D. K601D has a defective gp120-association, and was sequentially passaged in peripheral blood mononuclear cells to select for suppressor mutations. Mutations 136 and/or glycan 142 increased the sensitivity of T138N and ΔN. Drummer2013 (antibody interactions, glycosylation)
2G12: Clade A Env sequence, BG505, was identified to bind to bNAbs representative of most of the known NAb classes. This sequence is the best natural sequence match (73%) to the MRCA sequence from 19 Env sequences derived from PG9 and PG16 MAbs' donor. A point mutation at position L111A of BG505 enabled more efficient production of a stable gp120 monomer, preserving the major neutralization epitopes. The antisera produced by this adjuvanted formulation of gp120 competed with bnAbs from 3 classes of non-overlapping epitopes. 2G12 bound to BG505L111A monomer, but failed to neutralize BG505 pseudovirus. Hoffenberg2013 (antibody interactions)
2G12: The neutralization profile of 1F7, a human CD4bs mAb, is reported and compared to other bnNAbs. 1F7 exhibited extreme potency against primary HIV-1, but limited breadth across clades. 2G12 neutralized 33% of a cross-clade panel of 157 HIV-1 isolates (Fig. S1) while 1F7 neutralized only 20% of the isolates. Gach2013 (neutralization)
2G12: This study reported the Ab binding titers and neutralization of 51 patients with chronic HIV-1 infection on supressive ART for 3 yrs. A high titer of Ab against gp120, gp41, and MPER was found. Patient sera were evaluated for binding against recombinant gp120_JR-FL mutants lacking either the V1/V2 loop or the V3 loop. Significantly higher end point binding titers and HIV1_JR-FL neutralization were noticed in patients with >10 compared to <10 yrs of detectable HIV RNA. 2G12 was used as a CD4b Ab control. Gach2014 (neutralization, HAART, ART)
2G12: This study reports the development of a new cell-line (A3R5)-based highly sensitive Ab detection assay. This T-lymphoblastoid cell-line stably expreses CCR5 and recognizes CCR5-tropic circulating strains of HIV-1. A3R5 cells showed greater neutralization potency compared to the current cell-line of choice TZM-bl. 2G12 was used as a reference Ab in neutralization assay comparing A3R5 and TZM-bl. McLinden2013 (assay or method development)
2G12: The crystal structure of PGT135 with gp120, CD4 and Fab 17b was analyzed to study how PGT135 recognizes its Asn332 glycan-dependent epitope. The combined structural studies of PGT 135, PGT 128 and 2G12 show this Asn332-dependent epitope is highly accessible and much more extensive than initially appreciated, allowing for multiple binding modes and varied angles of approach, thus representing a supersite of vulnerability for antibody neutralization. Kong2013 (structure)
2G12: This is a review of identified bNAbs, including the ontogeny of B cells that give rise to these antibodies. Breadth and magnitude of neutralization, unique features and similar bNAbs are listed. 2G12 is a V3-glycan Ab, with breadth 18%, IC₅₀ 4.85 μg per ml, and its unique feature is glycan-only recognition. Kwong2013 (review)
2G12: A32 and 2G12 MAbs were used to trigger ADCC activity and to show that HIV Nef and Vpu protect HIV-infected CD4+ T cells from ADCC through down-modulation of CD4 and BST2. Pham2014 (ADCC)
2G12: A highly conserved mechanism of exposure of ADCC epitopes on Env is reported, showing that binding of Env and CD4 within the same HIV-1 infected cell effectively exposes these epitopes. The mechanism might explain the evolutionary advantage of downregulation of cell surface CD4v by the Vpu and Nef proteins. 2G12 was used in CD4 coexpression and competitive binding assay. Results showed a strong correlation of deletion of vpu gene and 2G12 binding. Veillette2014 (ADCC)
2G12: The ability of MAb A32 to recognize HIV-1 Env expressed on the surface of infected CD4(+) T cells as well as its ability to mediate antibody-dependent cellular cytotoxicity (ADCC) activity was investigated. This study demonstrates that the epitope defined by MAb A32 is a major target on gp120 for plasma ADCC activity. 2G12 was used as a control and A32 showed >3 fold higher ADCC activity than 2G12. Ferrari2011a (ADCC)
2G12: Env pseudo-typed viruses generated from 7 transmitting and 4 non-transmitting mothers and their children were studied to identify phenotypes that associate with the risk of mother to child transmission. There were no differences in neutralization with 2F5, 2G12, 4E10 and b12, but transmitting mothers had higher autologous NAb responses against gp120/gp41, suggesting that strong autologous neutralization activity can associate with risk of transmission and be in fact detrimental. Baan2013 (neutralization, mother-to-infant transmission)
2G12: A statistical model selection method was used to identify a global panel of 12 reference Env clones among 219 Env-pseudotyped viruses that represent the spectrum of neutralizing activity seen with sera from 205 chronically HIV-1-infected individuals. This small final panel was also highly sensitive for detection of many of the known bNAbs, including this one. The small panel of 12 Env clones should facilitate assessments of vacine-elicited NAbs. Decamp2014 (assay or method development)
2G12: A panel of NAbs and non-neutralizing Abs (NoNAbs) displaying the highest Fc γR-mediated inhibitory activity and significant ADCC were selected and formulated in a microbicidal gel and tested for their antiviral activity against SHIVSF162P3 vaginal challenge in non-human primates. Combination of 2G12, 2F5 and 4E10 fully prevented vaginal transmission. Two NoNAbs 246-D and 4B3 had no impact on viral acquisition, but reduced plasma viral load. Moog2014 (ADCC, SIV)
2G12: The complexity of the epitopes recognized by ADCC responses in HIV-1 infected individuals and candidate vaccine recipients is discussed in this review. 2G12 is discussed as the C2, C3, C4 and V4 glycation sites-targeting neutralizing anti-gp120 mAb exhibiting ADCC activity and having a discontinuous epitope. Pollara2013 (ADCC, review)
2G12: "Neutralization fingerprints" for 30 neutralizing antibodies were determined using a panel of 34 diverse HIV-1 strains. 10 antibody clusters were defined: VRC01-like, PG9-like, PGT128-like, 2F5-like, 10E8-like and separate clusters for b12, CD4, 2G12, HJ16, 8ANC195. This mAb belongs to 10E8-like cluster. Georgiev2013 (neutralization)
2G12: This paper reported the nature of junk Env glycan that undermine the development of Ab responses against gp120/gp41 trimers and evaluated enzyme digestion as a way to remove aberrant Env to produce "trimer VLPs". 2G12 with its high-mannose glycan profile showed binding to gp160ER, considered as VLP-contaminant. Crooks2011 (glycosylation)
2G12: This study described a potential novel conformational epitope that is present in a subtype C infected subject during early infection. This epitope was recognized by three different B cell receptors and elicited both glycan dependent and independent MAbs. This also showed the power of a single strategically placed amino acid change in viral escape. 2G12 was discussed as a BnAb directed against glycan in describing the role of "glycan shield" in viral escape. Lynch2011a (glycosylation, escape, cell-line isolated antibody)
2G12: The role of NK cells and NK cell receptor polymorphisms in the assessment of HIV-1 neutralization is reported. 2G12 was used in viral inhibition assay as a control to compare NK cells participation and activity. Brown2012 (neutralization, NK cells)
2G12: This study describes an ˜11 Angstrom cryo-EM structure of the trimeric HIV-1 Env precursor in its unliganded state. The three gp120 and gp41 subunits form a cage like structure with an interior void surrounding the trimer axis which restricts Ab access. 2G12 was used in ELISA to asses the recognition of the purified Env glycoproteins and recognized a high-mannose glycan array on the gp120 outer domain. Mao2012 (structure)
2G12: The sera of 20 HIV-1 patients were screened for ADCC in a novel assay measuring granzyme B (GrB) and T cell elimination and reported that complex sera mediated greater levels of ADCC than anti-HIV mAbs. The data suggested that total amount of IgG bound is an important determinant of robust ADCC which improves the vaccine potency. 2G12 was used as an anti-gp120 to study effects of Ab specificity and affinity on ADCC against HIV-1 infected targets. Smalls-Mantey2012 (ADCC, assay or method development)
2G12: Isolation of VRC06 and VRC06b MAbs from a slow progressor donor 45 is reported. This is the same donor from whom bnMAbs VRC01, VRC03 and NIH 45-46 were isolated and the new MAbs are clonal variants of VRC03. 2G12 was used as a glycan specific Ab and as a negative control to compare binding specificity of VRC06. Li2012
2G12: Immunogenicity of gp120 immunogens from two pairs of clade B and two pairs of clade C mother-to-child transmitted HIV-1 variants was studied in rabbits. While high level Env-specific antibody responses were elicited by all immunogens, their abilities to NAb responses differed and neutralization-resistant variants elicited broader NAb. Each of the six Env antigens resistant to 2G12 lacked at least one of the four Potential N-Linked Glycosylation sites (PNGS) important for 2G12 binding. Wang2012 (mother-to-infant transmission)
2G12: Protective potency of PGT121 was evaluated in vivo in rhesus macaques. PGT121 efficiently protected against high-dose challenge of SHIV SF162P3 in macaques. Sterilizing immunity was observed in 5/5 animals administered 5 mg/kg antibody dose and in 3/5 animals administered 0.2 mg/kg, suggesting that a protective serum concentration for PG121 is in the single-digit mg/mL. PGT121was effective at serum concentration 600-fold lower than for 2G12 and 100-fold lower than for b12. Moldt2012a (immunoprophylaxis)
2G12: The unbinding kinetics of the gp120-2G12, Man(4)-2G12, and Man(5)-2G12 interactions were measured by single-molecule force spectroscopy. This is the first single-molecule study aimed at dissecting the carbohydrate-antibody recognition of the gp120-2G12 interaction. The study confirmed crystallographic models that show both the binding of the linear Man(4) arm to 2G12 and also the multivalent gp120 glycan binding to 2G12. Martines2012 (binding affinity)
2G12: Three mouse B cell lines expressing domain-exchanged 2G12 WT, the non-domain-exchanged 2G12 I19R variant, and 2G12 gl as IgM B cell receptors (BCRs) were used to determine the potential of carbohydrate immunogens to elicit Y-shaped or domain-exchanged antibodies in vivo. HIV envelope glycoproteins and candidate glycoconjugate vaccines were compared for their ability to activate these B cell lines. Several of these immunogens were able to activate both 2G12 WT and 2G12 I19R B cell lines, and the discrete cluster of oligomannose glycans could selectively activate the domain-exchanged 2G12 WT cells. None of the immunogens tested were able to activate the germ line 2G12 B cells. The engineered B cell lines were more sensitive than standard ELISA binding assays and may help in the design of immunogens that elicit 2G12-like domain-exchanged antibodies in vivo. Doores2013 (assay or method development, glycosylation)
2G12: A computational tool (Antibody Database) identifying Env residues affecting antibody activity was developed. As input, the tool incorporates antibody neutralization data from large published pseudovirus panels, corresponding viral sequence data and available structural information. The model consists of a set of rules that provide an estimated IC₅₀ based on Env sequence data, and important residues are found by minimizing the difference between logarithms of actual and estimated IC₅₀. The program was validated by analysis of MAb 8ANC195, which had unknown specificity. Predicted critical N-glycosylation for 8ANC195 were confirmed in vitro and in humanized mice. The key associated residues for each MAb are summarized in the Table 1 of the paper and also in the Neutralizing Antibody Contexts & Features tool at Los Alamos Immunology Database. West2013 (glycosylation, computational epitope prediction)
2G12: Identification of broadly neutralizing antibodies, their epitopes on the HIV-1 spike, the molecular basis for their remarkable breadth, and the B cell ontogenies of their generation and maturation are reviewed. Ontogeny and structure-based classification is presented, based on MAb binding site, type (structural mode of recognition), class (related ontogenies in separate donors) and family (clonal lineage). This MAb's classification: gp120 glycan-V3 site, type glycans and domain swapping, 2G12 class, 2G12 family. Kwong2012 (review, structure, broad neutralizer)
2G12: This review discusses the new research developments in bnAbs for HIV-1, Influenza, HCV. Models of the HIV-1 Env spike and of Influenza visrus spike with select bnAbs bound are shown. Burton2012 (review)
2G12: Somatic hypermutations are preferably found in CDR loops, which alter the Ab combining sites, but not the overall structure of the variable domain. FWR of CDR are usually resistant to and less tolerant of mutations. This study reports that most bnAbs require somatic mutations in the FWRs which provide flexibility, increasing Ab breadth and potency. To determine the consequence of FWR mutations the framework residues were reverted to the Ab's germline counterpart (FWR-GL) and binding and neutralizing properties were then evaluated. 2G12, which recognizes carbohydrates, was among the 17 bnAbs which were used in studying the mutations in FWR. Fig S4C described the comparison of Ab framework amino acid replacement vs. interactive surface area on 2G12. Klein2013 (neutralization, structure, antibody lineage)
2G12: Antigenic properties of 2 biochemically stable and homogeneous gp140 trimers (A clade 92UG037 and C clade CZA97012) were compared with the corresponding gp120 monomers derived from the same percursor sequences. The trimers had nearly all the antigenic properties expected for native viral spikes and were markedly different from monomeric gp120. 2G12 bound trimers and monomers equally well, indicating that the epitope is fully accessible in both forms. Kovacs2012 (antibody binding site, neutralization, binding affinity)
2G12: Crystal structure and mechanistic analysis of 2F5-gp41 complex is reported. b12 has been referred as a BnAb directed against the exterior gp120 envelope glycoprotein. Ofek2004 (antibody interactions, structure)
2G12: Glycan shield of HIV Env protein helps to escape the Ab recognition. Several of the PGT BnAbs interact directly with the HIV glycan coat. Crystal structures of Fabs PGT127 and PGT128 showed that the high neutralizing potency was mediated by cross-linking Env trimers on the viral surface. 2G12 was discussed in terms of recognizing terminal dimannose and binding to glycan coat. Pejchal2011 (glycosylation, structure, broad neutralizer)
2G12: Intrinsic reactivity of HIV-1, a new property regulating the level of both entry and sensitivity to Abs has been reported. This activity dictates the level of responsiveness of Env protein to co-receptor, CD4 engagement and Abs. 2G12 has been used as a control CD4BS binding Ab in neutralization assays. Haim2011 (antibody interactions)
2G12: Glycan Asn332-targeting broadly cross-neutralizing (BCN) antibodies were studied in 2 C-clade infected women. The ASn332 glycan was absent on infecting virus, but the BCN epitope with Asn332 evolved within 6 months though immune escape from earlier antibodies. Plasma from the subject CAP177 neutralized 88% of a large multi-subtype panel of 225 heterologous viruses, whereas CAP 314 neutralized 46% of 41 heterologous viruses but failed to neutralize viruses that lack glycan at 332. CAP177 or CAP314 clones were not sensitive to 2G12. Moore2012 (neutralization, escape)
2G12: This study reports the isolation of a panel of Env vaccine elicited CD4bs-directed macaque mAbs and genetic and functional features that distinguish these Abs from CD4bs MAbs produced during chronic HIV-1 infection. 2G12 was used as a negative control Abs in competitive binding assay with non human primates mAbs. Sundling2012 (vaccine-induced immune responses)
2G12: The goal of this study was to improve the humoral response to HIV-1 by targeting trimeric Env gp140 to B cells. The gp140 was fused to a proliferation-inducing ligand (APRIL), B cell activation factor (BAFF) and CD40 ligand (CD40L). These fusion proteins increased the expression of activation-induced-cytidine deaminase (AID) responsible for somatic hypermutation, Ab affinity maturation, and Ab class switching. The Env-APRIL induced high anti-Env responses against tier1 viruses. 2G12 was used in BN-PAGE trimer shift assay. Melchers2012 (neutralization)
2G12: Existing structural and sequence data was analyzed. A set of signature features for potent VRC01-like (PVL) and almost PVL abs was proposed and verified by mutagenesis. 2G12 has been referred in discussing the breadth and potency of antiCD4 abs. West2012a (antibody lineage)
2G12: Synthesis of an engineered soluble heterotrimeric gp140 is described. These gp140 protomers were designed against clade A and clade B viruses. The heterotrimer gp140s exhibited broader anti-tier1 isolate neutralizing antibody responses than homotrimer gp140. 2G12 was used to determine and compare the immunogenicity of homo and heterotrimers gp140s. 2G12 didn't exhibit any difference in binding to homotrimeric clade A and clade B gp140 binding. Sellhorn2012 (vaccine antigen design)
2G12: This paper showed that nAb 2G12, which binds to gp120 N glycans with α (1,2)-linked mannose termini and inhibits replication after passive transfer to patients, neutralizes by slowing entry of adsorbed virus. It is suggested that 2G12 competitively inhibits interactions between gp120 V3 loop and the tyrosine sulfate containing amino terminus, thus reducing assembly of complexes that catalyze entry. Platt2012 (antibody interactions, glycosylation)
2G12: The use of computationally derived B cell clonal lineages as templates for HIV-1 immunogen design is discussed. 2G12 has been discussed in terms of immunogenic and functional characteristics of representative HIV-1 BnAbs and their reactions to antigens. Haynes2012 (antibody interactions, memory cells, vaccine antigen design, review, antibody polyreactivity, broad neutralizer)
2G12: Polyclonal B cell responses to conserved neutralization epitopes are reported. Cross-reactive plasma samples were identified and evaluated from 308 subjects tested. 2G12 was used as a control mAb in the comprehensive set of assays performed. Plasma samples C1-0763 and C1-0219 showed comparable activities with 2G12 in competition ELISA. Tomaras2011 (neutralization, polyclonal antibodies)
2G12: Role of envelope deglycosylation in enhancing antigenicity of HIV-1 gp41 epitopes is reported. The mechanism of induction of broad neutralizing Abs is discussed. The hypothesis of presence of "holes" in the naive B cell repertoires for unmutated B cell receptor against HIV-1 Env was tested. The authors inferred that glycan interferences control the binding of unmutated ancestor Abs of broad neutralizing mAb to Env gp41. Ma2011 (glycosylation, neutralization)
2G12: The rational design of vaccines to elicit broadly neutralizing antibodies to HIV-1 is discussed in relation to understanding of vaccine recognition sites, the structural basis of interaction with HIV-1 env and vaccine developmental pathways. 2G12 has been mentioned regarding the recognition of high-mannose glycans Kwong2011 (antibody binding site, glycosylation, neutralization, vaccine antigen design, review)
2G12: A single-cell Ab cloning method is described to isolate neutralizing Abs using truncated gp160 transfected cells as bait. Among the 15 Abs reported, only two are found to be broadly neutralizing and bind to a novel conformational HIV-1 spike epitope. 2G12 was used as a control in neutralizing assay. Klein2012 (neutralization)
2G12: Several antibodies including 10-1074 were isolated from B-cell clone encoding PGT121, from a clade A-infected African donor using YU-2 gp140 trimers as bait. These antibodies were segregated into PGT121-like (PGT121-123 and 9 members) and 10-1074-like (20 members) groups distinguished by sequence, binding affinity, carbohydrate recognition, neutralizing activity, the V3 loop binding and the role of glycans in epitope formation. 2G12 was used as a control in virus neutralization assay. Detail information on the binding and neutralization assays are described in the figures S2-S11. Mouquet2012a (glycosylation, neutralization, binding affinity)
2G12: YU2 gp140 bait was used to characterize 189 new MAbs representing 51 independent IgG memory B cell clones from 3 clade A or B HIV infected patients exhibiting broad neutralizing activity. 2G12 has been used as a positive control for epitope mapping and evaluating these anti-gp-140 antibodies and a non-sensitive control to DMR/AAA triple mutation. Mouquet2011 (neutralization)
2G12: A panel of glycan deletion mutants was created by point mutation into HIV gp160, showing that glycans are important targets on HIV-1 glycoproteins for broad neutralizing responses in vivo. Enrichment of high mannose N-linked glycan(HM-glycan) of HIV-1 glycoprotein enhanced neutralizing activity of sera from 8/9 patients. 2G12 was used as a control. Lavine2012 (neutralization)
2G12: Ab-driven escape and Ab role in infection control and prevention are reviewed. Main focus is on NAbs, but Ab acting through effector mechanisms are also discussed. 2G12 which was isolated in 1996 and discussed in the context of developing broadly cross-neutralizing antibodies. Overbaugh2012 (escape, review)
2G12: Antigenic properties of undigested VLPs and endo H-digested WT trimer VLPs were compared. 2G12 bound gp120 and Env-VLPs equivalently. There was no significant correlation between E168K+N189A WT VLP binding and 2G12 neutralization, while trimer VLP ELISA binding and neutralization exhibited a significant correlation. BN-PAGE shifts using digested E168K + N189A WT trimer VLPs exhibited prominence compared to WT VLPs. Tong2012 (neutralization, binding affinity)
2G12: The ability of several broadly neutralizing antibodies that bind gp10 or gp41 to inhibit cell-cell fusion between Clone69TRevEnv cells induced to express the viral envelope proteins, gp120/gp41 and highly CD4-positive SupT1 cells was investigated. Little or no inhibitory effect on cell-cell fusion was observed. MAbs b12, m14 IgG and 2G12 had moderate inhibitory activity; MAbs 4E10 and 2F5 had no inhibitory activity. Yee2011 (antibody interactions)
2G12: Plasma from 14 R5-tropic SHIV-infected macaques was screened for broadly neutralizing activity. A macaque with highly potent cross-clade plasma NAb response was identified. Longitudinal studies showed that the development of broad and autologous NAb responses occurred coincidentally in this animal. Serum-mapping studies, using pseudovirus point mutants and antigen adsorption assays, indicated that the plasma bNAbs are specific for epitopes that include carbohydrates and are critically dependent on the glycan at position 332 of Env gp120. MAb 2G12 was used for comparison. Walker2011a (neutralization, polyclonal antibodies)
2G12: The role of V1V2 in the resistance of HIV-1 to neutralizing Abs was studied using a panel of neutralization-sensitive and -resistant HIV-1 variants and through exchanging regions of Env between neutralization-sensitive and -resistant viruses. An increase in the length of the V1V2 loop and/or the number of potential N-linked glycosylation sites (PNGS) in that same region of Env was directly involved in the neutralization resistance. The virus that was sensitive to neutralization by autologous serum was also sensitive to neutralization by MAbs b12, 2G12, 2F5, and 4E10, while the virus that was resistant to neutralization by autologous serum was also resistant to neutralization by all of these antibodies except MAb 2G12. vanGils2011 (glycosylation, neutralization, escape)
2G12: A standardized proficiency testing program for measurements of HIV-1-specific NAbs in the TZM-bl assay was developed. Three rounds of optimization involving 21 different test laboratories were required to design the final proficiency testing kit. MAbs b12, 2G12, 2F5, 4E10 and TriMab (b12+2G12+2F5) were used for testing. Todd2012 (assay or method development)
2G12: The inhibitory activity of HIV-1-specific Abs against HIV-1 replication in langerhans cells (LCs) and interstitial dendritic cells (IDCs) was analyzed. Five well-known NAbs 447-52D, 4E10, b12, 2G12, 2F5 strongly inhibited HIV-1BaL and HIV-1TV1 replication in LCs and IDCs, and their inhibitory activities were stronger than those measured on PBMCs. Inhibition was more efficient by IgGs than corresponding IgAs, due to an Fc receptor-dependent mechanism, where HIV-1 inhibition occurs by binding of the Fc portion of IgGs to Fc receptors. Peressin2011 (genital and mucosal immunity, dendritic cells)
2G12: The reactivity profiles of MAbs 4E10, 2F5 and 2G12 to those of four pathogenic autoAbs derived from patients with antiphospholipid-syndrome (APS), and to serum from a patient with systemic lupus erythematosus (SLE) were compared using an autoantigen microarray comprising 106 connective tissue disease-related autoantigens. The reactivity profiles of bNt anti-HIV-1 MAbs were distinct from those of pathogenic autoAbs. Singh2011 (antibody polyreactivity)
2G12: Broadly neutralizing antibodies circulating in plasma were studied by affinity chromatography and isoelectric focusing. The Abs fell in 2 groups. One group consisted of antibodies with restricted neutralization breadth that had neutral isoelectric points. These Abs bound to envelope monomers and trimers versus core antigens from which variable loops and other domains have been deleted. Another minor group consisted of broadly neutralizing antibodies consistently distinguished by more basic isoelectric points and specificity for epitopes shared by monomeric gp120, gp120 core, or CD4-induced structures. The pI values estimated for neutralizing plasma IgGs were compared to those of human anti-gp120 MAbs, including 5 bnMAbs (PG9, PG16, VRC01, b12, and 2G12), 2 narrowly neutralizing MAbs (17b and E51), and 3 nonneutralizing MAbs (A32, C11, and 19e). bnMAbs VRC01, 2G12 and b12 had basic pIs (8.1 to >9). Sajadi2012 (polyclonal antibodies)
2G12: Small sized CD4 mimetics (miniCD4s) were engineered. These miniCD4s by themselves are poorly immunogenic and do not induce anti-CD4 antibodies. Stable covalent complexes between miniCD4s and gp120 and gp140 were generated through a site-directed coupling reaction. These complexes were recognized by CD4i antibodies as well as by the HIV co-receptor CCR5 and elicited CD4i antibody responses in rabbits. A panel of MAbs of defined epitope specificities, was used to analyze the antigenic integrity of the covalent complexes using capture ELISA. MAb 2G12 was used to normalize the concentration of gp140 vs gp140-miniCD4 complex. Martin2011 (mimics, binding affinity)
2G12: Sensitivity to neutralization was studied in 107 full-length Env molecular clones from multiple risk groups in various locations in China. Neutralization sensitivity to plasma pools and bNAbs was not correlated. MAbs 2F5 and G12 failed to neutralize almost all viruses in the C/07/08/B'C subtype group. 2F5 was potent in neutralizing viruses in subtype B′ and CRF01_AE, while 2G12, could only neutralize a 6/9 of subtype B′ viruses and none of the CRF01_AE viruses. 23/24 2G12-resistant viruses lacked the glycan at position 295 or 332 or both. Shang2011 (glycosylation, neutralization, subtype comparisons)
2G12: The long-term effect of broadly bNAbs on cell-free HIV particles and their capacity to irreversibly inactivate virus was studied. MPER-specific MAbs potently induced gp120 shedding upon prolonged contact with the virus, rendering neutralization irreversible. The kinetic and thermodynamic requirements of the shedding process were virtually identical to those of neutralization, identifying gp120 shedding as a key process associated with HIV neutralization by MPER bNAbs. Neutralizing and shedding capacity of 7 MPER-, CD4bs- and V3 loop-directed MAbs were assessed against 14 divergent strains. Neutralization with 2G12 was reversible, as 2G12 immediately lost the majority of neutralization activity once access antibody was removed. 2G12 induced 30-60% shedding with 5/14 probed viruses, suggesting that although not a potent shedding inducer, 2G12 can not be considered incapable of inducing shedding. Ruprecht2011 (neutralization, kinetics)
2G12: Circulating HIV-1 virion-immune complexes (ICs), present in approximately 90% of acute subjects were quantified, and the levels and antibody specificity to those in chronic infection were compared. Similar to a nonneutralizing anti-gp41 MAb 7B2, purified plasma IgG from acute HIV-1 subjects bound both infectious and noninfectious virions. This was in contrast to the neutralizing antibody 2G12 MAb that bound predominantly infectious virions. Liu2011c (binding affinity)
2G12: Gold nanoparticles coated with self-assembled monolayers of synthetic oligomannosides [manno-gold glyconanoparticles (GNPs)], which are present in gp120, bound 2G12 with high affinity and interfered with 2G12/gp120 binding. GNPs coated with a linear tetramannoside could block the 2G12-mediated neutralization of a replication-competent virus under conditions that resemble the ones in which normal serum prevents infection of the target cell. Marradi2011 (glycosylation, neutralization)
2G12: Deglycosylations were introduced into the 24 N-linked glycosylation sites of a R5 env MWS2 cloned from semen. Mutants N156-T158A, N197-S199A, N262-S264A and N410-T412A conferred decreased infectivity and enhanced sensitivity to a series of antibodies and entry inhibitors. Mutant N156-T158A showed enhanced neutralization sensitivity to MAb 17b in the absence of soluble CD4, suggesting that deglycosylation in these sites on gp120 may be beneficial for the exposure of a CD4 induced epitope which only exists in the CD4-liganded form of gp120. Huang2012 (glycosylation, neutralization)
2G12: This study analyzed the neutralization sensitivity of sequential HIV-1 primary isolates during their natural evolution in 5 subtype B and CRF02_AG HIV-1 infected drug naive individuals to 13 anti-HIV-1 MAbs (including this MAb) directed at epitopes in the V2, V3, CD4bd and carbohydrates. Patient viruses evolved to become more sensitive to neutralization by MAbs directed at epitopes at V2, V3 and CDbd, indicating that cross sectional studies are inadequate to define the neutralization spectrum of MAb neutralization with primary HIV-1 isolates. Haldar2011 (neutralization)
2G12: This is a detailed systematic study of the molecular recognition of five synthetic oligomannosides 1–5 in solution by the antibody 2G12 by using ligand-based NMR techniques, specifically saturation transfer difference (STD) NMR spectroscopy and transferred NOE experiments. Enriquez-Navas2011 (glycosylation, structure)
2G12: The sensitivity to PG9 and PG16 of pseudotyped viruses was analysed carrying envelope glycoproteins from the viral quasispecies of three HIV-1 clade CRF01_AE-infected patients. It was confirmed that an acidic residue or a basic residue at position 168 in the V2 loop is a key element determining the sensitivity to PG9 and PG16. In addition, evidence is provided of the involvement of a conserved residue at position 215 of the C2 region in the PG9/PG16 epitopes. B clones were tested against 2G12 MAb recognizing a conformational glycan-dependent epitope on gp120 but 2G12 was not used for the CRF01_AE clones since all of them lacked the N332 residue, which constitutes one of the essential N-glycosylation sites of the 2G12 epitope. 2G12 sensitivity of B clones remained comparable, with only one resistant clone, 5008CL3, which became moderately sensitive. Thenin2012a (neutralization)
2G12: Given the potential importance of cell-associated virus during mucosal HIV-1 transmission, sensitivity of bNAbs targeting HIV-1 envelope surface unit gp120 (VRCO1, PG16, b12, and 2G12) and transmembrane domain gp41 (4E10 and 2F5) was examined for both cell-free and mDC-mediated infections of TZM-bl and CD4+ T cells. It was reported that higher gp120-bNAb concentrations, but not gp41-directed bNAb concentrations, are required The IC50 and IC90 for anti-gp120–directed bNAb 2G12, were significantly higher for almost all mDC-mediated virus transmission (Lai, NL4-3, Lai/Balenv), compared with cell-free HIV-1 infection.to inhibit mDC-mediated virus spread, compared with cell-free transmission. Only cell-free and mDC-mediated infection of 89.6 virus particles demonstrated no significant IC50 difference against 2G12. 2G12 did not readily bind mDCs in the absence of virus. Around 18% of the mDC–T cell synaptic junctions displayed colocalization of Gag-eGFP VLPs with 2G12. Furthermore, 2G12 did not localize at DC–T cell synaptic junctions in the absence of Gag-eGFP VLPs. Sagar2012 (neutralization, binding affinity)
2G12: To overcome the many limitations of current systems for HIV-1 virus-like particle (VLP) production, a novel strategy was developed to produce HIV-1 VLP using stably transfected Drosophila S2 cells by cotransfecting S2 cells with plasmids encoding an envelope glycoprotein (consensus B or consensus C), a Rev-independent Gag (Pr55) protein, and a Rev protein, along with a pCoBlast selection marker. Except for antigenic epitope PG16, all other broadly neutralizing antigenic epitopes 2G12, b12, VRC01, and 4E10 tested are preserved on spikes of HIV-1 VLP produced by S2 clones. Yang2012 (assay or method development, neutralization)
2G12: In order to increase recognition of CD4 by Env and to elicit stronger neutralizing antibodies against it, two Env probes were produced and tested - monomeric Env was stabilized by pocket filling mutations in the CD4bs (PF2) and trimeric Env was formed by appending trimerization motifs to soluble gp120/gp14. PF2-containing proteins were better recognized by bNMAb against CD4bs and more rapidly elicited neutralizing antibodies against the CD4bs. Trimeric Env, however, elicited a higher neutralization potency that mapped to the V3 region of gp120. Feng2012 (neutralization)
2g12: A way to produce conformationally intact, deglycosylated soluble, cleaved recombinant Env trimers by inhibition of the synthesis of complex N-glycans during Env production, followed by treatment with glycosidases under conditions that preserve Env trimer integrity is described to facilitate crystallography and immunogenicity studies. As expected, the glycan-dependent 2G12 did not bind to the deglycosylated trimers. Depetris2012 (glycosylation, binding affinity)
2G12: The sera of 113 HIV-1 seroconverters from three cohorts were analyzed for binding to a set of well-characterized gp120 core and resurfaced stabilized core (RSC3) protein probes, and their cognate CD4bs knockout mutants. 2G12 bound strongly to RSC3, RSC3/G367R and RSC3 Δ3711, weakly bound to RSC3 Δ3711/P363N, very weakly bound to gp120 core and did not bind to gp120 core D368R. Lynch2012 (binding affinity)
2G12: Sensitivity to bNAbs of primary R5 HIV-1 isolates sequentially obtained before and after AIDS onset was studied. End-stage disease HIV R5 isolates were more sensitive to neutralization by TriMab, an equimolar mix of the IgGb12, 2F5 and 2G12 antibodies, than R5 isolates from the chronic phase. The increased sensitivity correlated with low CD4+ T cell count at time of virus isolation and augmented viral infectivity. Envs from end-stage R5 variants had increased positive surface charge and reduced numbers of potential N-linked glycosylation sites (PNGS). These molecular changes in Env also correlated to sensitivity to neutralization by the individual 2G12 MAb. Molecular modeling suggested that the glycosylation sites lost at end-stage disease are located in close proximity to the 2G12 epitope. Borggren2011 (glycosylation, neutralization)
2G12: To test whether HIV-1 particle maturation alters the conformation of the Env proteins, a sensitive and quantitative imaging-based Ab-binding assay was used to probe the conformations of full-length and cytoplasmic tail (CT) truncated Env proteins on mature and immature HIV-1 particles. Binding of MPER-specific MAb Z13e1 to immature particles was greater than to mature virions and the increase was abolished by truncation of the gp41 CT. Z13e1 bound immature particles approximately 1.5 to 2 times as well as mature particles when the median binding signals were compared indicating that the recognized neutralization-sensitive epitopes undergo conformational masking during HIV-1 particle maturation. Joyner2011 (binding affinity)
2G12: Humoral responses to specific, linear gp41 epitopes were that were already known to be the target of broadly neutralizing antibodies were compared in a cohort of sub-Saharan mother-child pairs. TriMab positive-control Abs (2F5, 2G12, and b12) neutralized all viruses tested: the subtype B laboratory strains SF162 (R5-B) and IIIB (X4-B), and the low-sensitivity subtype C strains, primary isolates DU172 and DU156 (both R5-C). The TriMab control inhibited strain DU156 when all neutralization assays were performed on the DU156 HIV isolate (C-R5) with cord blood specimens from EUN babies. Diomede2012 (neutralization, mother-to-infant transmission, subtype comparisons)
2G12: The possibility to construct a polyepitope B-cell immunogen (TBI-2g12) containing linear mimetics of conformational epitopes and its immunogenic properties was examined. The aim was to select the most active peptide mimetic recognized by MAb 2G12 and to construct the protein immunogen by attaching the selected peptide mimotope VGAFGSFYRLSVLQS to a protein carrier. It was shown that the TBI-2g12 as well as the original TBI induce antibodies, that recognize HIV-1 proteins, TBI protein using ELISA and immunoblotting. Though only anti-TBI-2g12 serum recognized the synthetic peptide mimotope VGAFGSFYRLSVLQS, whereas the antibodies against original TBI don’t recognize it. The neutralization assay demonstrated that serum antibodies of the mice immunized with TBI-2g12 possess virus neutralizing activity suggesting that principal epitope responsible for virus neutralizing activity was formed from VGAFGSFYRLSVLQS peptide in the structure of TBI-2g12 protein. Karpenko2012 (mimotopes, neutralization)
2G12: 162 full-length envelope (env) clones were generated from plasma RNA obtained from 5 HIV-1 Clade B infected mother-infant pairs and their V1-V5 genotypes and phylogeny were extensively characterized. All clones from three infants were resistant to 2G12 and exhibited mutations eliminating one of five PNGS implicated in 2G12 binding. Most maternal clones from these pairs exhibited similar levels of 2G12 resistance, and displayed the corresponding mutations. Kishko2011 (neutralization, mother-to-infant transmission)
2G12: HIV-1 adaptation to neutralization by MAbs VRC01, PG9, PG16 was studied using HIV-1 variants from historic (1985-1989) and contemporary (2003-2006) seroconverters. 2G12 was included for comparison and neutralized 5% of contemporary viruses at IC50 < 1 μ g/ml and 14% at IC50 < 5 μ g/ml. TriMab construct, consisting of MAbs b12, 2F5 and 2G12 in equal concentrations, showed the highest neutralization correlation with 2F5 and little similarity with 2G12. Euler2011 (neutralization)
2G12: The neutralization potency of PG9, PG16, VRC01 and PGV04 was approximately 10-fold greater than that of MAbs b12, 2G12, 2F5 and 4E10. Falkowska2012 (neutralization)
2G12: Neutralizing antibody repertoires of 4 HIV-infected donors with remarkably broad and potent neutralizing responses were probed. 17 new monoclonal antibodies that neutralize broadly across clades were rescued. All MAbs exhibited broad cross-clade neutralizing activity, but several showed exceptional potency. Although 2G12 neutralized 32% of 162 isolates at IC50<50 μg/ml, it was almost 100-fold less potent than several new antibodies PGT 121-123 and 125-128, for which the median antibody concentration required to inhibit HIV activity by 50% or 90% (IC50 and IC90 values) was almost 100-fold lower than that of b12, 2G12 and 4E10. Walker2011 (neutralization)
2G12: Studies were conducted to determine whether differences in immunogenic potential exist between two previously reported primary Env antigens (Clade B primary Env antigens LN40 and B33) with closely related gene sequences and completely different phenotypic features. The B33 Env is resistant to MAb 2G12, while the LN40 Env, having the opposite phenotype of B33, is sensitive to MAb 2G12. Vaine2011 (neutralization)
2G12: HIV-1 subtype C env genes from 19 mother-infant pairs: 10 transmitting in utero (IU) and 9 transmitting intrapartum (IP) were analyzed. A severe genetic bottleneck during transmission was confirmed in all pairs. Compared to the maternal viral population, viruses transmitted IP tended to have shorter variable loops and fewer putative N-linked glycosylation sites than viruses transmitted IU. The pseudotyped viruses displayed some sensitivity to 4E10 and soluble CD4 but were resistant to 2G12, 2F5, and IgG1b12. Russell2011 (glycosylation, neutralization, mother-to-infant transmission)
2G12: The influence of potential N-linked glycosylation site (PNGS) N302 on 2G12 sensitivity was assessed based on chimeric envelope genes created by swapping the V1V2 domains of the two env clones. Both the exchange of the V1V2 domain and the introduction of the PNGS at N302 on the 2G12-sensitive clone induced a significant decrease in sensitivity to 2G12. In contrast, the reverse V1V2 exchange and the removal of the PNGS at N302 on the 2G12-resistant clone increased sensitivity to 2G12, confirming the influence of these regions on 2G12 sensitivity. It suggests that both the V1V2 loop and an additional PNGS in V3 might limit access to the 2G12 epitope. Chaillon2011 (glycosylation, neutralization, structure)
2G12: To elicit 2G12-like Ab response it was shown that Manα1→2Man motif was the primary carbohydrate neutralization determinant of HIV-1 that elicited Abs to the self oligomannose glycans. While 2G12 is known to bind to this motif, the specificity of the mannan immune serum (ΔMnn1: S. cerevisiae deficient in the α1→3 mannosyltransferase gene) seemed narrower than some alternative modes of binding postulated for 2G12. ΔMnn1 immune sera revealed fine carbohydrate specificity to Manα1→2Man units, closely matching that of 2G12. The sera also appeared to tolerate the presence of D1 glucosylation indicating perhaps a somewhat wider degree of monosaccharide or linkage specificity compared to 2G12. Dunlop2010 (antibody binding site)
2G12: The development and characterization of a tier 1 R5 SHIV, termed SHIV-1157ipEL is reported. SHIV-1157ipEL is a chimera of the "early", neutralization-sensitive SHIV-1157ip envelope and the "late", neutralization-resistant engineered backbone of SHIV-1157ipd3N4. Molecular modeling revealed a possible mechanism for the increased neutralization resistance of SHIV-1157ipd3N4 Env: V2 loops hindering access to the CD4 binding site, shown experimentally with NAb b12. Sequence analysis performed of the SHIV-1157ipEL-p showed a loss of N295, a key amino acid residue in the epitope of 2G12 that caused SHIV-1157ipEL to become resistant to 2G12. 2G12 only neutralized SHIV-SF162P4 out of the 4 C clade and 2 B clade SHIV strains tested. Siddappa2010 (neutralization, vaccine antigen design, subtype comparisons)
2G12: Purified MAb 2G12, produced by transient expression in Nicotiana benthamiana using replicating and non-replicating systems based on deleted versions of Cowpea mosaic virus (CPMV) RNA-2, was expressed and characterized based on biochemical properties, in vitro activity and neutralization capabilities. The plant derived purified 2G12 (delRNA-2 + RNA-1 or CPMV-HT) was not as pure as CHO-produced 2G12 (reference standard) although no significant differences were observed between 2G12 produced by delRNA-2 with RNA-1 or by CPMV-HT. Also, 2G12 glycosylation was not greatly affected by the presence of RNA-1 or CPMV-HT. The binding activity of plant derived 2G12 was slightly lower than CHO-produced 2G12 although its neutralization capability was similar to that of CHO-produced 2G12. Sainsbury2010 (glycosylation, neutralization, binding affinity)
2G12: This review discusses current understanding of Env neutralization by antibodies in relation to epitope exposure and how this insight might benefit vaccine design strategies. This MAb is in the list of current MAbs with notable cross-neutralizing activity. Pantophlet2010 (neutralization, variant cross-reactivity, review)
2G12: This review outlines the general structure of the gp160 viral envelope, the dynamics of viral entry, the evolution of humoral response, the mechanisms of viral escape and the characterization of broadly neutralizing Abs. The review discusses the special structure of 2G12 which allows it to overcome the glycan masking strategy that HIV-1 uses to protect itself from antibody recognition. It is noted also that 2G12 can neutralize a significant number of primary isolates from clade B, but is less effective against non-clade B viruses and is not active against most clade C. 2G12 provided protection in macaques against SHIV. Gonzalez2010 (neutralization, variant cross-reactivity, escape, review)
2G12: The expression and characterization of different glycoforms of V3-Fc fusion protein along with its binding to HIV-neutralizing Abs 2G12 and 447-52D was examined. The binding affinity of 2G12 was significantly high for the high-mannose type glycoforms of V3-Fc (V3-Fc-HM, V3-Fc-M9 and the two mutants:N301A and Fc-N297A) following a quick association/dissociation kinetic process, although it was not measurable for the complex type glycoform V3-Fc-CT. The affinity to 2G12 was reduced more by removal of the N-glycan at the N301 site than at the N297 site. Very high affinity to 2G12 was observed for gp120 with extremely slow dissociation rate. Yang2010a (glycosylation, binding affinity)
2G12: This review discusses recent rational structure-based approaches in HIV vaccine design that helped in understanding the link between Env antigenicity and immunogenicity. This MAb is mentioned in the context of immunogens based on the epitopes recognized by bNAbs. 2G12 adopts an unusual domain exchanged structure to recognize a conserved cluster of oligomannose residues on the outer domain of gp120 and has provided a basis for the design of immunogens to target the HIV-1 glycan shield. Walker2010a (neutralization, review)
2G12: 37 Indian clade C HIV-1 Env clones obtained at different time points from five patients with recent infection, were studied in neutralization assays for sensitivities to their autologous plasma antibodies and mAbs. All Env variants were resistant to 2G12, except those obtained from IVC-3 patient. This resistance was associated with the absence of N-linked glycosylation site at position 295 at the N-terminal base of V3 loop. The sensitivity of IVC-3 clones was due to the presence of N295, atypical of clade C. Ringe2010 (neutralization)
2G12: This review discusses strategies for design of neutralizing antibody-based vaccines against HIV-1 and recent major advances in the field regarding isolation of potent broadly neutralizing Abs. Sattentau2010 (review)
2G12: The effect of absence and presence of sCD4 on accessibility and binding of HIV-1 gp41 MPER-binding epitopes on CCR5-tropic pseudoviruses from five different clades to the mAbs was studied. The 2G12 N-sites 295, 332, 339, 386, 392 were examined. 2G12 showed high binding affinity to pseudoviruses from clade A (epitope mutant:tWFDIs), clade B (NWFDIT) and clade D (NWFsIT), and very low binding affinity to clade A (NWFDIs), clade B (sWFsIT), clade C (sWFsIT), clade D (NWFsIT) and clade CRF01_AE (NWFDIT) and no binding to clade C (sWFsIT) and clade CRF01_AE (NWFDIs). Peachman2010a (variant cross-reactivity, binding affinity, subtype comparisons)
2G12: Most of the 34 Env-pseudotyped viruses from HIV-1 CRF01_AE - infected plasma samples collected in China could efficiently infect target cells in the presence of high concentrations of 2G12 MAb. Only 1/34 viruses showed low 2G12 susceptibility and all viruses lacked one or more glycans at positions critical for 2G12 neutralization. Nie2010 (glycosylation, neutralization)
2G12: This review discusses the studies done on poly-reactive antibodies (binding to two different epitopes), and the importance of polyreactivity. Low polyreactivity has been reported for 2G12. Pluckthun2010 (review, antibody polyreactivity)
2G12: A lentiviral vector encoding the heavy and light chains of 2G12 was transduced in the primary human B cells and directed production of 2G12. NOD/SCID/γc mice were transplanted with human hematopoetic stem cells (hu-HSC) transduced with the vector and the animals were inoculated with HIV-1. Mice engrafted with the 2G12-transducted cells displayed a 70-fold reduction in plasma RNA levels and a 200-fold reduction in HIV-1 infected spleen cells compared to control mice, indicating inhibition of in vivo HIV infection by this gene therapy approach. Joseph2010
2G12: This paper shows that a highly neutralization-resistant virus is converted to a neutralization sensitive virus with a rare single mutation D179N in the C-terminal portion of the V2 domain for several antibodies. 2G12, however, did not neutralize any of the mutants tested. ORourke2010 (neutralization, variant cross-reactivity)
2G12: MAb m9 showed superior neutralization potency compared to 2G12 in a TZM-bl assay, where it neutralized all 15 isolates compared to 2G12 that neutralized only 4 clade B isolates but not clade A or C isolates. Zhang2010 (neutralization)
2G12: A side-by-side comparison was performed on the quality of Ab responses in humans elicited by three vaccine studies focusing on Env-specific Abs. Minimal presence of 2G12-like Abs was detected in the three vaccine trials. 17% of sera from the HVTN 203 trial, 0% of sera from the HVTN 041 trial, and 24% of sera from the DP6-001 trial were able to outcompete binding to 2G12 MAb. Vaine2010 (antibody interactions)
2G12: This review focuses on recent vaccine design efforts and investigation of broadly neutralizing Abs and their epitopes to aid in the improvement of immunogen design. NAb epitopes, NAbs response to HIV-1, isolation of novel mAbs, and vaccine-elicited NAb responses in human clinical trials are discussed in this review. Mascola2010 (review)
2G12: Naturally occurring human and experimentally induced murine and rabbit GBV-C E2 Abs were studied for their ability to neutralize diverse HIV-isolates and showed that broadly neutralizing HIV Abs were elicited on immunization of rabbits with GBV-C E2. MAb 2G12 neutralized R5 and dual R5-X4 HIV-1 isolates of subtypes A and B in primary human PBMCs. The TriMAb control including 2G12 did not neutralize the HIV-1 R5 isolate in TZM-bl cells but did in PBMCs. Mohr2010 (neutralization)
2G12: A mathematical framework is designed to determine the number of Abs required to neutralize a single trimer called the stoichiometry of trimer neutralization. 15 different virus antibody combinations divided into five groups based on antibody binding sites were used in the designed model. 2G12 is in a group by itself as it recognizes a carbohydrate-dependent epitope on gp120. The number of 2G12 Abs needed to neutralize a single trimer was estimated as 1 with 97 percent probability. Magnus2010
2G12: BanLec is a lectin isolated from the fruit of bananas that was shown to inhibit HIV-1 isolates of different subtypes and tropisms. Pretreatment of gp120 with BanLec inhibited recognition by 2G12 in a dose-dependent manner, indicating that BanLec inhibits HIV-1 by binding to high-mannose structures also recognized by 2G12. Swanson2010
2G12: Four human anti-phospholipid mAbs were reported to inhibit HIV-1 infection of human PBMC's by binding to monocytes and releasing soluble chemokines. The ability of different anti-phospholid mAbs to inhibit pseudovirus infection was studied. Four out of nine anti-phospholid mAbs inhibited HIV-1 infectivity in PBMC-based virus infection inhibition assay where a mixture of mAbs 2F5, IgG1b12, and 2G12 (TriMab) was used as a positive control. Moody2010 (neutralization)
2G12: A naturally occurring dimeric form of 2G12 was shown to have increased neutralization potency and increased ADCC activity compared to the monomeric form of 2G12. An ADCC-enhancing double mutation improved the ADCC activity of 2G12 monomer more than 2G12 dimer. Klein2010a (ADCC)
2G12: Targeted neutralizing epitopes have been identified based on the change in sensitivity to neutralization due to variations in known immunoepitopes studied in 17 subjects. The glycan removal by N332S mutant from gp120 outer domain decreased the neutralization of gp160 by 2G12. In addition, the N332S mutant escaped neutralization by two patient sera. Nandi2010 (neutralization, escape)
2G12: Molecular modeling was used to construct a 3D model of an anti-gp120 RNA aptamer, B40t77, in complex with gp120. Externally exposed residues of gp120 that participated in stabilizing interaction with the aptamer were mutated. Binding of 2G12 to gp120 was inhibited by B40t77, which is suggested to be due to distant conformational changes of gp120 induced by the aptamer. Joubert2010 (binding affinity, structure)
2G12: A yeast glycosylation mutant was created to expose numerous terminal Man1,2-Man residues. Although the yeast did not bind to 2G12, immunization of rabbits resulted in sera containing Manα1,2-Manα1,2-Man-specific Abs that cross-reacted with Env glycoproteins from HIV-1 subtypes A, B and C. Luallen2010 (glycosylation, vaccine antigen design)
2G12: 2G12 was shown to capture virion particles completely devoid of HIV-1 Env. Virus capture assay was modified with added incubation of virions and MAbs in solution followed by removal of unbound MAbs, which nearly eliminated the Env-independent binding by this Ab. This modification also allowed for relative affinity of 2G12 for virions to be quantified. There was an overall reduction in the efficiency of capture of molecular clones (MC) relative to pseudotyped virions by 2G12. In addition, trimeric JR-FL MC was captured more efficiently by 2G12 than nontrimeric Envs from JR-CSF MC virus. Leaman2010 (assay or method development, binding affinity)
2G12: The role of HIV-1 envelope spike density on the virion and the effect it has on MAb avidity, and neutralization potencies of MAbs presented as different isotypes, are reviewed. Engineering approaches and design of immunogens able to elicit intra-spike cross-linking Abs are discussed. Klein2010 (review)
2G12: 18 unique Env clones of subtype C HIV-1 derived from six African countries and Scotland were tested for their neutralization susceptibility by 2G12. 2G12 neutralized only one of the isolates. Koh2010a (neutralization)
2G12: Glycoconjugates were designed consisting of four- and eight-valent high-mannose HIV-1 related oligosaccharides clustered onto flexible polyamidoamine (PAMAM) dendrons and subsequently conjugated to well-characterized nontoxic diphtheria toxin mutant CRM197 as a carrier. The multivalent presentation of oligomannoses increased the avidity to 2G12. Antisera of mice and rabbits immunized with the glycoconjugates failed to recognize recombinant HIV-1 proteins. Kabanova2010 (glycosylation, vaccine antigen design, binding affinity)
2G12: The effect of presence and absence of V1 loop was assessed using two approaches: remove V1 loop from the soluble trimeric gp140 construct (ΔV1SF162gp140) and second, substitute the V1 loop on SF162gp140 construct with four different V1 loops from 89.6, YU2, JRFL, and HxB2 (heterologous HIV-1 viruses). Deletion or substitution of V1 loop did not affect neutralization by 2G12 and there was only a small change in binding affinity to 2G12. D368R modification to SF162gp120 did not affect the binding by 2G12, although it abrogated neutralization by 2G12 at lower MAb concentrations. Ching2010 (neutralization, binding affinity)
2G12: A hybrid nonself sugar was designed based on the crystal structure of D-fructose in complex with 2G12 Fab to elicit high 2G12 Ab response based on much enhanced (9 times) affinity of 2G12 for D-fructose compared to D-mannose. Introduction of nonself modifications into the D1 arm of high-mannose sugars led to additional interactions of nonself modifications to the 2G12 binding site resulting in enhanced antigenicity. The nonself glycan enhanced 2G12 binding compared to the self glycan, and the antibodies generated in immunized rabbits cross-reacted with the self glycan present in different conjugates, but did not bind the self D1 glycan motif when present on gp120. Doores2010c (glycosylation, binding affinity)
2G12: The effect of HIV-1 complement opsonization on 2G12 activity was evaluated in three instances: HIV-1 transcytosis through epithelial cells, HIV-1 attachment on immature monocyte derived dendritic cells (iMDDC), and infectivity of iMDDC. 2G12 was not able to inhibit HIV-1 transcytosis. 2G12 inhibited the attachment of non-opsonised HIV to iMDDC but had no effect on the opsonized HIV-1 attachment. 2G12 was able to inhibit production of both opsonized and non-opsonized HIV-1 in iMDDCs. Jenabian2010 (complement)
2G12: A germ line version of 2G12 was constructed that was not domain exchanged and did not detectably bind to gp120. Introducing increasing number of substitutions to germ line 2G12 resulted in domain exchanged wild type form of this Ab. Only 5-7 crucial substitutions were found necessary to induce considerable domain exchange of germ line 2G12; Ih19, Rh57, Eh75, Rh39, Ah14, Vh84 and Ph113. Huber2010 (antibody binding site)
2G12: Clustering analysis was performed to find patterns of neutralization reactivity for the dataset of 103 patients sera against 20 viruses. The clustering by five MAbs (including 2G12) against the 20 isolates was less statistically robust than that with serum titers, resulting in three clusters for both cases. The membership in an isolate cluster defined by serum titers was compared with its sensitivity to every MAb to understand the relationship of serum and MAb reactivity. Membership in all the three clusters did not correlate with sensitivity to 2G12. Doria-Rose2010 (neutralization)
2G12: The sensitivity of subtype C viruses to lectins GRFT, CV-N and SVN was analysed and compared to that of subtype A and B viruses which showed same sensitivity by all three viruses for all the three lectins. It was also examined whether lectin binding interfered with the access to the 2G12 epitope and there was competition among the compounds for virus capture. GRFT and CV-N inhibited the virus capture more effectively than SVN. Virus capture by 2G12 was inhibited for all three viruses using same amount of lectin concentrations. The results suggested overlap of 2G12 epitope with the binding sites of all the three lectins. Alexandre2010 (binding affinity)
2G12: Addition of bacterial endotoxin (LPS) had no effect on the potency of 2G12 neutralization in TZM-bl assay but addition of LPS in PBMC assay increased neutralization potency of 2G12. Endotoxin contamination was shown to mediate release of antiviral chemokines in PBMCs and is thus suggested to be able to cause false-positive results in PBMC-based neutralization assays. Geonnotti2010 (neutralization)
2G12: In order to overcome problems of the PBMC-based neutralization assay a novel approach was developed utilizing a platform based on Renilla luciferase (LucR) expressing HIV-1 proviral backbone. Env-IMC-LucR reporter viruses expressing HIV-1 envs from different virus strains were incubated with NAbs, such as 2G12, and used to infect donor PBMCs. The inhibition was assessed by measuring virus-encoded LucR activity in the cell lysates. There was a dosage dependent effect of 2G12 on virus infectivity. Variation in sensitivity to 2G12 was observed among different donor PBMCs, and this high variability was suggested to be a real biological effect attributable to use of different donor PBMCs, rather than assay-to-assay variability. Edmonds2010 (assay or method development, neutralization)
2G12: The identity of N-linked glycans from primary isolates of subtypes A, B and C was studied. Results showed highly conserved virus-specific glycan profile devoid of medial Golgi-mediated processing. When mutant viruses with glycosylation site deletions that disrupt the 2G12 epitope were analyzed, there was a modest decrease of Man8-9GlcNAc2 glycans, but the overall profile remained unperturbed. This confirmed the sensitivity of 2G12 for a small subset of Manα1-2Man glycans. Doores2010b (glycosylation)
2G12: Subtype B HIV-1 variants from historical seroconverters (individuals that seroconverted between 1985 and 1989) were equally sensitive to neutralization by 2G12 as variants isolated from contemporary seroconverters (ndividuals that seroconverted between 2003 and 2006). Bunnik2010a (neutralization, dynamics)
2G12: 17b was linked with sCD4 and the construct was tested for its neutralization breadth and potency. sCD4-17b showed significantly greater neutralization breadth and potency compared to 2G12, neutralizing 100% of HIV-1 primary isolates of subtypes A, B, C, D, F, CRF01_AE and CRF02_AG, while 2G12 neutralized some isolates of subtypes B and D. Unlike sCD4-17b, 2G12 was not equivalently active against virus particles generated from different producer cell types. Lagenaur2010 (neutralization, variant cross-reactivity, subtype comparisons)
2G12: A set of Env variants with deletions in V1/V2 was constructed. Replication competent Env variants with V1/V2 deletions were obtained using virus evolution of V1/V2 deleted variants. Sensitivity of the evolved ΔV1V2 viruses was evaluated to study accessibility of their neutralization epitopes. 2G12 neutralized and bound to both cleaved and uncleaved ΔV1V2 variants more potently compared to the wild type virus, indicating better accessibility of the 2G12 epitope when the V1V2 domain is deleted. Bontjer2010 (neutralization, binding affinity)
2G12: Five different glycoforms of 2G12, generated in wild type and glycoengineered plants and in Chinese hamster ovary cells, were used to investigate the impact of Ab Fc glycosylation on the antiviral activity of the Ab. All five 2G12 glycoforms had similar binding profiles to cells expressing FcγRI, FcγRIIa or FcγRIIb. In contrast, two glycoforms of 2G12 lacking fucose showed significantly enhanced binding to cells expressing FcγRIIIa, compared to 2G12 glycoforms carrying core fucose. The two non-fucosylated forms of 2G12 also showed stronger antiviral activity against HIV-1 and SIV in ADCVI-assays compared to the fucosylated forms of 2G12. Forthal2010 (glycosylation, binding affinity)
2G12: A single amino acid substitution (I19R) was used to produce a nondomain-exchanged variant of 2G12 (2G12 I19R). 2G12 I19R was able to recognize the same mannose motifs on recombinant gp120, synthetic glycoconjugates, and on Candida albicans as the wild type 2G12. However, 2G12 I19R was unable to recognize the cluster of mannose motifs in the context of HIV envelope trimer, and was unable to neutralize 2G12-sensitive HIV-1 pseudovirions. Crystallographic structure of 2G12 I19R showed that this Ab and the wild type 2G12 have identical Fab binding units but that they display dramatically different juxtapositioning of their variable versus constant regions. These differences lead to remarkably different binding characteristics. Doores2010a (glycosylation, neutralization, binding affinity, structure)
2g12: Various UV-activatable azido- and iodo-based hydrophobic compounds have been studied for their ability to inactivate HIV-1 virus while preserving their surface antigenic structures. The virus was inactivated by treating it with azido-containing hydrophobic compounds and UV irradiation. The preservation of known neutralizing epitopes on the viral surface of treated virus was tested using the known neutralizing Abs. There was no significant effect on 2g12 recognition and capture of the virus treated with azido-compounds and irradiated with UV for 2 or 15 minutes compared to the untreated virus, hence no damage to its epitopes. Belanger2010 (binding affinity)
2G12: This review discusses recent research done to improve the production, quality, and cross-reactivity of binding Abs, neutralizing Abs, monoclonal Abs with broad neutralizing activity, antibody-dependent cell-mediated cytotoxicity (ADCC), antibody-dependent cell-mediated viral inhibition (ADCVI), and catalytic Abs. Studies focusing on several aspects of BNAb roles in vaccine development, and studies done to better understand the broad binding capacity of BNAbs are reviewed. Baum2010 (ADCC, neutralization, review)
2G12: Parent and GnTI (complex glycans of the neutralizing face are replaced by fully trimmed oligomannose stumps) viruses were equally sensitive to neutralization by 2G12, indicating that replacement of complex glycans does not affect the already exposed 2G12 epitope on the silent domain of the virus. Absence of the glycan at residue N301 (N301Q mutant virus) had no effect on 2G12 neutralization. Viruses subjected to removal of outer domain glycans by Endo H treatment were recognized less efficiently by 2G12. Binley2010 (glycosylation, neutralization)
2G12: Pseudoviruses containing Env mutations (V255E, S375N or A433T), which were in vitro selected with the small CD4-mimicking compound NBD-556, showed the same neutralization sensitivities as the wild type virus to 2G12. Yoshimura2010 (mimics, neutralization)
2G12: Neutralizing sensitivity of L669S mutant virus to 2G12 was not significantly different from the neutralizing sensitivity of the wild type virus. Shen2010 (neutralization)
2G12: Neutralization potency of 2G12 was compared to that of HK20 scFv in TZM-based assay using 45 Tier 1 and Tier 2 HIV isolates. 2G12 neutralized 12/45 isolates. In addition, 2G12 was used in TriMab, together with 2F5 and b12, to examine neutralization of 9 clade A, B, C, D and E isolates in PBMC assay. Here, TriMab neutralized 7 isolates with 2 not determined. Sabin2010 (neutralization, variant cross-reactivity, subtype comparisons)
2G12: Using a humanized mouse model it was shown that passively transferred 2G12 dimer was more potent than 2G12 monomer at preventing CD4 T cell loss and suppressing increase in viral load in mice challenged with JR-CSF virus. 100µg/ml of combined 2G12 monomer and dimer significantly reduced the severity of HIV-1 infection in mice with high-dose challenge, but this 2G12 dose resulted in escape mutations at the N295 residue. Providing 2G12 dimers continuously at 5-25µg/ml by IgG tumor backpacks in mice resulted in effective protection against HIV-1, while complete escape to 2G12 neutralization was not observed. Luo2010 (immunoprophylaxis, neutralization, escape, immunotherapy)
2G12: B cell depletion in an HIV-1 infected patient using rituximab led to a decline in NAb titers and rising viral load. Recovery of NAb titers resulted in control of viral load, and the newly emerged virus population was examined. The common ancestor of this new viral population showed evidence of positive selection and presence of N339E mutation, which inhibited neutralization by 2G12 fourfold. However, there was no binding competition between patient sera and 2G12. Huang2010 (antibody interactions, escape)
2G12: The role of several N-glycosylation sites in 2G12 binding and neutralization was investigated on Envs of LN40 and B33 strains. Glycans at N295, N332, N386 and N392 were critical for 2G12 binding and neutralization. Substitutions in Envs which affect CD4 binding were also shown to have a strong effect on 2G12 neutralization. These residues were within and proximal to CD4bs but not involved in glycosylation. Increased avidity to CD4 did not correlate with 2G12 sensitivity, indicating that the determinants within CD4bs may act to reorient glycans on gp120. Duenas-Decamp2010 (antibody binding site, glycosylation, neutralization, kinetics, binding affinity)
2G12: Unlike for b12, decreasing neutralization sensitivity during the course of infection was not observed for 2G12 in 15 patients studied. Changes in three amino acid residues (154, 178 and 389) were found to confer resistance to b12, but they did not increase resistance of LAI strain to 2G12 neutralization. Bunnik2010 (neutralization)
2G12: Fusion of CD4 with 2G12 scFv resulted in CD4-scFv2G12 reagent with neutralization potency improved by inclusion of an IgG Fc region and by linkage of CD4 to the heavy chain of 2G12. The resulting CD4hc-IgG12G12 was, like 2G12, expressed as a mixture of monomers and dimers. CD4hc-IgG12G12 dimers showed comparable neutralization potencies with 2G12, and CD4hc-IgG12G12 monomers showed enhanced neutralization potencies. Unlike 2G12, CD4hc-IgG12G12 had the ability to neutralize some clade C HIV-1 strains. West2010 (neutralization, variant cross-reactivity, subtype comparisons)
2G12: The specificities and structural analyses of 2G12 binding to Env are reviewed. This review also summarizes data on the evolution of HIV neutralizing Abs, principles of Env immunogen design to elicit broadly neutralizing Abs, and future critical areas of research for development of an Ab-based HIV vaccine. Hoxie2010 (vaccine antigen design, review)
2G12: Three 2G12 heavy chain mutants with multiple germ line amino acid substitutions in the VDJ region were created to investigate the mechanism of domain swapping in 2G12. There were qualitative structural differences between 2G12 mutants and 2G12 wild type, and the mutants failed to neutralize or to capture free virus. Structural analyses revealed that the domain-exchanged configuration of 2G12 was fostered by single or combined effects of 4 amino acid side chains that help stabilize the elbow region (H113). The proline at H113 was not required for the domain swapping capability of 2G12. 2G12-3H6 mutant, which had the whole Vh region exchanged with that of another Ab (3H6), lacked domain swapping capability, indicating that CDR3 and J region are not sufficient to promote Vh domain exchange. Gach2010 (neutralization, binding affinity, structure)
2G12: 58 mAbs, including 3 broadly neutralizing mAbs, were isolated from memory B cells of HIV-1 infected donors using an improved EBV immortalization method combined with a broad screening strategy. 2G12 neutralization activity was compared to the three new broadly neutralizing mAbs. 2G12 did not compete for binding to gp120 with any of the new mAbs. 2G12 neutralized 67% of Tier 1 and 23% of Tier 2 viruses, the neutralization of Tier 2 viruses being inferior to that of the new MAb HJ16. 2G12 rarely neutralized clade C isolates. Corti2010 (neutralization)
2G12: 433 Abs were cloned from HIV envelope-binding memory B cells from 6 patients with broadly neutralizing sera. The Abs had neutralizing activity directed against several epitopes on gp120 and the majority neutralized Tier 1 viruses. Tier-2 neutralization was observed only with mixtures of MAbs, but only at high concentrations. 2G12 was used as a control and it neutralized 4/5 Tier 1 and 4/5 Tier 2 viruses. Scheid2009 (neutralization)
2G12: Exogenous epitope tags were introduced in different parts of three variable regions, V1, V2 and V4, of two HIV isolates, SF162 and SF33. Almost all SF162 and SF33 tagged Envs were as susceptible to neutralization by 2G12 as the wild type, except V4-tagged Envs, which were significantly more resistant to neutralization by this Ab compared to wild type. However, V4-tagged Envs were recognized by 2G12. Wallace2009 (antibody binding site, neutralization)
2G12: This review discusses obstacles to elicitation of protective NAbs, recent data on viral epitopes vulnerable to broadly NAbs, qualitative and quantitative implications of NAb response for vaccine development, and possible future areas of investigation to improve understanding of Env structure and stimulation of appropriate B cell responses. Stamatatos2009 (review)
2G12: The structure and dynamic of the virion spike and the 2G12 epitope are discussed. Challenges to eliciting broadly neutralizing anticarbohydrate response, such as weak protein-carbohydrate interactions and small size of glycan patches for Ab binding, are reviewed. 2G12 domain swapping solution to these problems and the implication of the data for immunogen design are discussed. Schief2009 (antibody binding site, review)
2G12: TZM-bl and PBMC systems were compared to investigate the influence of target cell environment on HIV entry inhibition. The sensitivity of TZM-bl system was confirmed by inhibitory capacity of 2G12, 2F5 and b12. Virus entry increased on addition of polycation additives, but neither concentration nor type of polycation had a significant impact on the inhibitory activity of 2G12. 2G12 was shown to be significantly less active on TZM-bl cells, where it failed to inhibit 12 viruses, while it failed to inhibit 9 viruses in PBMC assay. HIV isolates were less sensitive to inhibition by 2G12, 2F5 and 4E10, with up to 100-fold lower sensitivity in the TZM-bl assay. Rusert2009 (assay or method development, neutralization)
2G12: To examine the antigenicity of a defined Ab epitope on the functional envelope spike, a panel of chimeric viruses engrafted at different positions with the hemagglutinin (HA) epitope tag was constructed. The neutralization sensitivity of the all but three HA-tagged viruses to 2G12 was similar to the neutralization sensitivity of wild type virus to this Ab. The three viruses with HA-tag insertions in the V4 region were more resistant to 2G12 than the wild type virus. Pantophlet2009 (neutralization)
2G12: This review summarizes targets of autologous neutralizing Abs (AnAbs) in early and chronic infections. V1V2 is a frequent target of AnAbs, while V4 and V5 have marginal role and anti-V3 Abs do not contribute to autologous neutralization. In addition to variable regions, C3 is a neutralization target in subtype C viruses, and is thought to interact with V4. gp41 is thought to have marginal effect as a target of AnAbs, with only one study showing 4E10-resistant variants suggesting escape from AnAbs targeting this region. AnAb specificities and sequential development, and their role in preventing superinfection is also reviewed. The relatively high Ab titer required for prevention of superinfection and control of viremia, and the low inhibitory potential of b12, 2F5, 4E10 and 2G12 compared to antiretroviral drugs is discussed. Moore2009 (autologous responses, review)
2G12: This review describes obstacles that have been encountered in the development of an HIV-1 vaccine that induces broadly neutralizing Abs, and unusual features of existing broadly neutralizing Abs, such as 2G12. Importance of identification and characterization of new epitopes, and of B-cell stimulation, is discussed. Montefiori2009 (review)
2G12: An overview of the different expression strategies to over produce HIV neutralizing Abs, including 2G12, in plants. The attention is specially focused on expression strategies of Nef protein. Marusic2009 (review)
2G12: Env clones of 6 out of 12 viruses were shown to be highly sensitive to neutralization by 2G12 in PBMC assay but were not inhibited by 2G12 in TZM-bl assay. All 6 envelopes carried a mutation in the core epitope of 2G12. Viruses from patients receiving passive immunization with 2G12 were sensitive to 2G12 both in vivo and in PBMC assay. Upon emergence of 2G12 resistant viruses in vivo, the viruses were shown resistant to neutralization by 2G12 in PBMC assay. The study suggests that TZM-bl assay can fail to detect neutralizing activity of in vivo relevance but may be more prone to detect epitope mismatches. Causes of the observed differences between the PBMC and TZM-bl assays were due to virus producer cells and target cells, that could influence virus entry inhibition. Mann2009 (assay or method development, neutralization)
2G12: NAb specificities of a panel of HIV sera were systematically analyzed by selective adsorption with native gp120 and specific mutant variants. The integrity and specificity of gp120 beads in adsorption assay were validated by their ability to adsorb binding activity of 2G12. gp120 point mutation D368R was used to screen the sera for CD4bs- Abs, and it was shown that this mutant could adsorb binding activity of 2G12. To test for presence of coreceptor binding region MAbs in sera, gp120 I420 mutant was used. This mutant was recognized by 2G12 at equal levels as the wild type, and it could adsorb binding activity of 2G12 in adsorption assay. In some of the broadly neutralizing sera, the gp120-directed neutralization was mapped to CD4bs. Some sera were positive for NAbs against coreceptor binding region. A subset of sera also contained NAbs directed against MPER. Li2009c (assay or method development)
2G12: 2G12 domain swapping mode of epitope recognition is reviewed in detail. The review also summarizes on how different modes of Ab binding and recognition are used to overcome viral evasion tactics and how this knowledge may be used to re-elicit responses in vivo. Kwong2009a (antibody binding site, review)
2G12: The review discusses the implications of HIV-1 diversity on vaccine design and induction of neutralizing Abs, and possible novel approaches for rational vaccine design that can enhance coverage of HIV diversity. Patterns of within-clade and between-clade diversity in core epitopes of known potent neutralizing Abs, including 2G12, is displayed. Korber2009 (review)
2G12: 2G12 alone was not able to trigger complement-mediated lysis (CML) of 93BR020 and 92UG037 strains, however, it did so in combination with 4E10. Lysis experiments of viruses from three donors showed that 2G12 in combination with allotype-specific Abs Cw4 or Cw7 significantly increased CML. 2G12 in combination with Abs against HLA A1 resulted in significant reduction in CML. Hildgartner2009 (complement)
2G12: The effect of continuous 2G12 infusion on protection from infection and on viral load is reviewed. Haigwood2009 (immunoprophylaxis, review)
2G12: FcγR-mediated inhibition and neutralization of HIV by 2G12 and other MAbs is reviewed. The review also summarizes the role of ADCC and ADCVI Abs on HIV infection inhibition and neutralization. Forthal2009 (review)
2G12: A set of Env variants with deletions in V1/V2 were constructed. Replication competent Env variants with V1/V2 deletions were obtained using virus evolution of V1/V2 deleted variants. Most variants were found more sensitive to neutralization by 2G12 than the wild type, indicating that deletion of V1/V2 increases 2G12 epitope accessibility. Bontjer2009 (antibody binding site, neutralization)
2G12: This review summarizes novel approaches to mapping broad neutralizing activities in sera and novel technologies for targeted MAb retrieval. Binley2009 (assay or method development, review)
2G12: Resurfaced stabilized core 3 (RSC3) protein was designed to preserve the antigenic structure of the gp120 CD4bs neutralizing surface but eliminate other antigenic regions of HIV-1. RSC3 retained strong reactivity with 2G12. Memory B cells were selected that bound to RSC3 and full IgG mAbs were expressed. Binding profiles of the three newly detected mAbs (VRC1, VRC2 and VRC3) were compared to binding profile of 2G12. Wu2010 (binding affinity)
2G12: Glycosylation patterns of HIV-1 were altered using different glycosidase inhibitors or a mutant cell line. Recombinant production of gp120 in the presence of kifunensine resulted in increased neutralization by 2G12, while swainsonine and NB-DNJ treatment resulted in neutralization similar to the wild type. Doores2010 (glycosylation, neutralization)
2G12: In 25% of cases, the broad and potent neutralizing activity of sera from elite neutralizers displayed critical correlation to the N-linked glycosylation at position 332 of HIV-1. Although this N-linked glycan is important for formation of the 2G12 epitope, none of the donor sera inhibited 2G12 binding to gp120, indicating presence of NAbs distinct of 2G12. Unlike PG9 and PG16, 2G12 neutralized kifunensine-treated pseudoviruses with similar potency as wild type pseudoviruses. Walker2010 (glycosylation, neutralization, binding affinity)
2G12: Ab gene divergence analyses found that 2G12 Ab was significantly more divergent from the closest germline Abs than were hmAbs against other viruses. Germline-like 2G12 was constructed in a scFv format. It was shown that germline-like 2G12 did not bind to recombinant gp140 although the corresponding mature 2G12 showed binding. Xiao2009 (binding affinity, antibody sequence)
2G12: Patient sera from 13 HIV controllers and 75 chronic viremic patients were tested for the ability to block binding of 2G12 to Env JRFL gp140 oligomers. There was no difference observed between the controllers and chronic viremic patients. The NAb response was significantly lower in controllers, while ADCC was detected in all controllers but in only 40% of viremic patients. Lambotte2009 (elite controllers, neutralization)
2G12: One functional Env clone from each of 10 HIV-1 infected seroconverting individuals from India were analyzed for their sensitivity to MAbs and plasma pools of subtypes B, C and D. All 10 Envs were resistant to 2G12, and the resistance was associated with the absence of a PNLG at position 295. HIVIG neutralized all 10 Envs, and the Envs were most sensitive to neutralization by subtype C pool, followed by subtype D and B pools, respectively. Amino acid signature patterns that associated with neutralization clusters were found. Signature patterns included PNLG at positions 295, 392 and 448, which participate in the 2G12 epitope. Kulkarni2009 (glycosylation, neutralization, acute/early infection)
2G12: Combinations of loop alternations, filling hydrophobic pockets (F-mutations) and introduction of inter-domain cysteine pairs (D-mutations) were used to construct four immunogens with stabilized gp120 core. Modified truncations of the V1V2 and the V3 loop had no impact on 2G12 binding. However, introduction of stabilizing F and D mutations in one case slightly reduced 2G12 affinity and in other two cases slightly increased it. Dey2009 (binding affinity)
2G12: A review about the in vivo efficacy of 2G12 and other MAbs against HIV-1, and about inhibition of HIV-1 infection by Ab fragments Fab, scFv and engineered human Ab variable domains or "domain antibodies" (dAbs). Chen2009b (neutralization, immunotherapy, review)
2G12: Env derivatives from R3A TA1 virus with eliminated V1 and V2 regions, truncated V3, and deleted cleavage, fusion, and interhelical domains were able to bind 2G12. A membrane anchored variant of this outer domain glycoprotein was also shown to bind to 2G12. Truncations of the β20-β21 hairpin increased reactivity with 2G12. Replacement of the central 20 amino acids of the V3 loop with a basic hexapeptide further significantly increased binding to 2G12. Wu2009a (binding affinity)
2G12: During purification of 2G12 from mammalian cells, two forms of 2G12 were discovered, a monomeric and a dimeric form. The 2G12 dimer had an average increased potency of 82-fold compared to the monomer and was able to neutralize three out of 20 strains not neutralized by the monomer. Clade C strains were resistant to neutralization by both 2G12 dimer and monomer. A dimeric form of 2G12 was constructed that was more potent in neutralization of 2G12-sensitive strains than the monomeric form. There was no significant difference observed in binding of 2G12 dimers and monomers to gp120. West2009 (neutralization, kinetics, binding affinity)
2G12: 2G12 neutralization breadth and potency was compared to that of two broadly neutralizing Abs PG9 and PG16 in a panel of 162 multi-clade viruses. 2G12 exhibited lower neutralization potency than PG9 and PG16. 2G12 bound with high affinity to both monomeric gp120 and trimeric Env. Binding of 2G12 to Endo H and mock treated gp120 was determined. Walker2009a (neutralization, variant cross-reactivity, binding affinity)
2G12: NL4.3 virus was cultured with cyclotriazadisulfonamide (CADA) and CADA-resistant virus was selected. 2G12 MAb showed a slightly higher neutralizing potency against the CADA-resistant virus compared to wildtype. The mutations in CADA-resistant virus are suggested to stabilize the conformation of gp120 and reduce glycosylation. Vermeire2009 (neutralization)
2G12: Glyco-engineered tobacco plants were used for efficient expression of recombinant 2G12 with quantitative β1,4-galactosylation (AA structure). Antigen binding capacity of 2G12 glycoforms compared to CHO-derived 2G12 was 115-140%. Neutralization activity of fully galactosylated 2G12 was more than 3 times higher than that of other plant-derived glycoforms and CHO-derived 2G12. Strasser2009 (neutralization, binding affinity)
2G12: An analytical selection algorithm and a reduced virus screening panel were created for assessment of serum neutralizing activity. It is suggested that selection of pseudoviruses for neutralization assays should focus on the overall resistance profile of the pseudovirus and against MAbs b12, 4E10, 2F5 and 2G12. Neutralization profiles of all viruses used for screenings were determined for 2G12. Simek2009 (neutralization)
2G12: Substantial increase in neutralization potency (58-fold) of 2G12 was observed in cells expressing FcγRI against HIV 6535.3 virus strain while there was no effect on the neutralization potency of this Ab against QH0692 strain. With virus SC422661.8, FcγRIIa and FcγRIIb impaired the neutralizing activity of 2G12, suggesting possible infection enhancement. Perez2009 (enhancing activity, neutralization)
2G12: Aqueous two-phase partition system (ATPS) was used to successfully separate 2G12 from unclarified tobacco extract with a yield of 85%. ATPS was successfully combined with affinity chromatography and yielded Ab was stable without any major contaminating proteins or degraded Ab variants. Platis2009a (assay or method development)
2G12: Δ49-12a, a mutant virus derived from an in-vitro passaged virus with four residues removed from the V3 stem, was shown to be completely resistant to CCR5 inhibitors but was 3-fold more sensitive to neutralization by 2G12 compared to the parental R3A virus. TA1, a mutant with a 15 amino acid deletion of the distal half of V3, was resistant to neutralization by 2G12. Nolan2009 (neutralization)
2G12: Swarm analysis of viruses from one patient resulted in isolation of several different clones with different neutralization sensitivities against four HIV-1 positive sera. None of the clones were sensitive to neutralization by 2G12. ORourke2009 (neutralization, acute/early infection)
2G12: Binding of 2G12 to gp120 was not inhibited by YZ23, an Ab derived from mice immunized with eletcrophilic analogs of gp120 (E-gp120), indicating no overlap of these MAb epitopes. Nishiyama2009
2G12: Binding of 2G12 to various lipid antigens was studied. 2G12 did not bind to any lipids. Matyas2009
2G12: There was no association between 2G12 Abs and anticardiolipin in serum samples from slow progressors. Martinez2009 (autoantibody or autoimmunity)
2G12: By manipulation of the glycosylation machinery of S. cerevisiae a heavily glycosylated yeast protein, Pst1, was identified, that presents closely arrayed N-glycans. Pst1 produced in TM yeast bound 2G12 with high affinity and was able to inhibit 2G12 binding to gp120 more efficiently than a heterologous gp120 from the same subtype. Pst1 was also able to inhibit 2G12 neutralization of HxB and SF162 Env. Luallen2009 (antibody binding site, glycosylation, neutralization, kinetics, binding affinity)
2G12: Subtype A gp140 SOSIP trimers bound to 2G12. Sera from rabbits immunized with SOSIP gp140 and gp120 were unable to capture pseudovirions of the homologous virus by 2G12. 2G12 was unable to bind to the 295 N/A mutant of the virus. Kang2009
2G12: Five rhesus macaques were intravenously treated with 40mg/kg 2G12, which resulted in a high 2G12 serum concentration, and challenged with SHIV SF162P3. Three animals were protected against infection. One animal showed delayed and lower peak viremia compared to controls. Sequence analysis of one of the infected animals showed presence of T388A mutation disrupting the N-glycosylation consistent with escape. Thus, 2G12 can offer protection at relatively low titers, where a titer of 1:1 was sufficient to protect 60% of animals against infection. Vaginal concentrations of 2G12 and b12 were similar when compared in 3 animals, and thus unlikely to contribute to protection differences between the two MAbs. Hessell2009 (glycosylation, neutralization, escape, immunotherapy, rate of progression)
2G12: Ten new non-neutralizing, cross-reactive mAbs were found in immunized mice. 2G12 only reacted with a subset of different Env subtypes tested. 2G12 also reacted with cells expressing A1.con, B.con, B_17779 and B_MN Envs. None of the new mAbs could bind free virus particles while 2G12 did. Binding of 2G12 to B_JRFL oligomer was not blocked by any of the newly detected mAbs. Gao2009 (variant cross-reactivity)
2G12: The heavy and light chains of 2G12 were expressed in transgenic tobacco plants. The accumulation of the Ab chains was increased 2-3-fold by elastin-like peptide (ELP) fusion in both leaves and seeds of the plant. The quality of leaf-derived Abs was comparable to 2G12 generated in CHO cells, and the presence of ELP did not affect N-glycan processing nor intracellular trafficking. Plant-derived 2G12 lacking ELP was more efficient in neutralizing HIV-1 than CHO-2G12, but the fusion of ELP to either of the Ab chains significantly reduced the neutralization efficacy. Floss2009 (neutralization, kinetics, binding affinity)
2G12: An international collaboration (NeutNet) was organized to compare the performance of a wide variety of HIV-1 neutralization assays performed in different laboratories. Four neutralizing agents were evaluated: 4E10, 447-52D, sCD4 and TriMab (equal mixture of 2F5, 2G12 and 4E10). For TriMab, the mean IC50 values were always lower in the pseudovirus assays than in virus infectivity assays. In general, there were clear differences in assay sensitivities that were dependent on both the neutralizing agent and the virus. No single assay was capable of detecting the entire spectrum of neutralizing activities. Fenyo2009 (assay or method development, neutralization)
2G12: Gene encoding gp140 was fused with three trimerization motifs, T4F, GCN and ATC. gp140, gp140(-)(with mutations in the furin-cleavage site), gp140(-)T4F and gp140(-)GCN bound 2G12 as well, or better than, gp120. gp140(-)ATC bound 2G12 less strongly than gp120. Du2009 (binding affinity)
2G12: Four groups of Abs were detected in a CRF02_AG infected patient directed against mimotopes of MPER, V3, C1 and LLP2. Out of four pseudoviruses from 4 different time points of infection, only one showed moderate susceptibility to 2G12. Dieltjens2009 (neutralization)
2G12: A phylogenetic analysis of gp120 evolution was performed in patients with different patterns of disease progression. In the LNTP patient group, and in 2 NPs, many N-linked glycosylation sites were shown to be under positive selection and exposed on the surface, indicating that Abs binding close to or to 2G12 binding site exert selective pressure on the viral surface in some patients. Canducci2009 (glycosylation, rate of progression)
2G12: Neutralization profiles of cloned Envs derived from recent heterosexual infections by subtypes A, C, D, and A/D from Kenya were determined. The transmitted env variants were generally resistant to neutralization by 2G12, as only 4/31 variants were neutralized by this Ab. These were also the only variants that maintained all five PNGS within the 2G12 epitope. Blish2009 (neutralization, acute/early infection)
2G12: This report investigated whether mannose removal alters gp120 immunogenicity in mice. Approximately 55 mannose residues were removed from gp120 by mannosidase digestion creating D-gp120 for immunization. 2G12 was unable to bind to D-gp120, indicating that 2G12 epitope was eliminated and that the mannosidase digestion was functional. Banerjee2009 (glycosylation, binding affinity)
2G12: HIV-1 variants derived from 5 patients at different timepoints during chronic infection were analysed for their sensitivity to neutralization by b12, 2G12, 2F5 and 4E10. In four of the patients, almost all variants from all time points were resistant to neutralization by 2G12. In two of these patients, resistance to neutralization coincided with the absence of N-linked glycans at position 339 at all time points. In one patient, resistance to neutralization by 2G12 correlated with absence of N-linked glycans at positions 295, 332 and/or 339, and in the second patient, resistance correlated with absence of glycans at positions 295, 339, 386, and/or 339. In the fifth patient, early viruses were sensitive to neutralization by 2G12, but late variants were resistant, which coincided with the loss of N-linked glycans at either 386 or 392 positions. Bunnik2009 (glycosylation, neutralization, escape)
2G12: 2G12 neutralized infection of PBLs with various HIV-1 strains with high potency. However, 2G12 did not inhibit transcytosis of cell-free or cell-associated virus across a monolayer of epithelial cells. A mixture of 13 MAbs directed to well-defined epitopes of the HIV-1 envelope, including 2G12, did not inhibit HIV-1 transcytosis, indicating that envelope epitopes involved in neutralization are not involved in mediating HIV-1 transcytosis. When the mixture of 13 MAbs and HIV-1 was incubated with polyclonal anti-human γ chain, the transcytosis was partially inhibited, indicating that agglutination of viral particles at the apical surface of cells may be critical for HIV transcytosis inhibition by HIV-specific Abs. Chomont2008 (neutralization)
2G12: 5 loop structures surrounding the CD4 binding site in the gp120 liganded conformation were identified that may protect gp120 from Abs. Loops A, B, C and E were located in the C2, C3, C4 and C5 regions respectively, and loop D was situated in the V5 region. Binding of 2G12 to gp120 was unaffected by loop deletions, as this Ab bound equally to HIV-1 IIIB wild type and its loop B deletion mutant, and to HIV-1 89.6 wild type and its loop C deletion mutant. Berkower2008 (binding affinity)
2G12: A reference panel of recently transmitted Tier 2 HIV-1 subtype B envelope viruses was developed representing a broad spectrum of genetic diversity and neutralization sensitivity. The panel includes viruses derived from male-to-male, female-to-male, and male-to-female sexual transmissions, and CCR5 as well as CXCR4 using viruses. The envelopes displayed varying degrees of neutralization sensitivity to 2G12, with 11 of 19 envelopes sensitive to neutralization by this Ab. Schweighardt2007 (assay or method development, neutralization)
2G12: Pre-treatment of gp120 with 2G12 strongly inhibited induction of IL-10, indicating that interaction between gp120 and a mannose C-type lectin receptor is a critical trigger for IL-10 induction. Shan2007
2G12: Modeling of protein-protein interaction based on the gp120 crystal structure, X-ray crystal structure of 2G12 and its complexes with glycans, suggested that the glycans attached to N295 and N302 from the V3 loop are the two most likely involved in the conformational epitope of 2G12. Sirois2007 (review, structure)
2G12: A chimeric protein entry inhibitor, L5, was designed consisting of an allosteric peptide inhibitor 12p1 and a carbohydrate-binding protein cyanovirin (CNV) connected via a flexible linker. The L5 chimera inhibited 2G12-gp120 interaction, as did CNV alone, indicating that the chimera has the high affinity binding property of the CNV molecule. McFadden2007
2G12: This review summarizes data on possible vaccine targets for elicitation of neutralizing Abs and discusses whether it is more practical to design a clade-specific than a clade-generic HIV-1 vaccine. Development of a neutralizing Ab response in HIV-1 infected individuals is reviewed, including data that show no apparent division of different HIV-1 subtypes into clade-related neutralization groups. Also, a summary of the neutralizing activity of MAb 2G12 in different HIV-1 clades is provided. McKnight2007 (variant cross-reactivity, review)
2G12: HIV-1 passaged in the presence of chloroquine was observed to have lost two glycosylation sites important for 2G12 binding, at positions 332 and 397 in the gp120 region, indicating that the drug can alter the immunogenic properties of gp120. Naarding2007
2G12: This review provides information on the HIV-1 glycoprotein properties that make it challenging to target with neutralizing Abs. 2G12 structure and binding to HIV-1 envelope and current strategies to develop versions of the Env spike with functional trimer properties for elicitation of broadly neutralizing Abs, such as 2G12, are discussed. In addition, approaches to target cellular molecules, such as CD4, CCR5, CXCR4, and MHC molecules, with therapeutic Abs are reviewed. Phogat2007 (review)
2G12: This review summarizes current knowledge on the various functional properties of antibodies in HIV-1 infection, including 2G12 MAb, in vivo and in vitro activity of neutralizing Abs, the importance and downfalls of non-neutralizing Abs and antibodies that mediate antibody-dependent cellular cytotoxicity and the complement system, and summarizes data on areas that need future investigation on Ab-mediated immune control. Huber2007 (review)
2G12: A new high throughput method was developed for neutralization analyses of HIV-1 env genes by adding cytomegalovirus (CMV) immediate enhancer/promoter to the 5' end of the HIV-1 rev/env gene PCR products. The PCR method eliminates cloning, transformation, and plasmid DNA preparation steps in the generation of HIV-1 pseudovirions and allows for sufficient amounts of pseudovirions to be obtained for a large number of neutralization assays. Pseudovirions generated with the PCR method showed similar sensitivity to 2G12 Ab, indicating that the neutralization properties are not altered by the new method. Kirchherr2007 (assay or method development, neutralization)
2G12: 2G12 structure, binding, neutralization, and strategies that can be used for vaccine antigen design to elicit 2G12-like Abs, are reviewed in detail. Lin2007 (vaccine antigen design, review, structure)
2G12: This review summarizes 2G12Ab epitope, properties and neutralization activity. 2G12 use in passive immunization studies in primates and possible mechanisms explaining protection against infection are discussed. Kramer2007 (immunotherapy, review)
2G12: gp120 proteins were developed with double mutation T257S+S375W, which alters the cavity at the epicenter of the CD4 binding region, and used to immunize rabbits. The ability of rabbit sera to affect binding of CD4 to unmodified gp120 proteins was tested. CD4 binding to gp120 was unaffected by 2G12. Dey2007a (antibody binding site)
2G12: The various effects that neutralizing and non-neutralizing anti-envelope Abs have on HIV infection are reviewed, such as Ab-mediated complement activation and Fc-receptor mediated activities, that both can, through various mechanisms, increase and decrease the infectivity of the virus. The importance of these mechanisms in vaccine design is discussed. The unusual features of the 2G12 MAb, and its neutralization capacities, are described. Willey2008 (neutralization, review)
2G12: Current insights into CTLs and NAbs, and their possible protective mechanisms against establishment of persistent HIV/SIV infection are discussed. Pre- and post-infection sterile and non-sterile protection of NAbs against viral challenge, and potential role of NAbs in antibody-mediated antigen presentation in modification of cellular immunity, are reviewed. Use of 2G12 in immunization experiments and its in vivo anti-viral activity in suppression of viral rebound in HIV-1 infected humans undergoing structured treatment interruptions are described. Yamamoto2008 (immunotherapy, supervised treatment interruptions (STI), review)
2G12: A yeast strain was produced (TM) with a deletion of genes encoding two key carbohydrate processing enzymes, Och1 and Mnn1, that resulted in efficient recognition of the TM yeast by 2G12 MAb. Four heavily glycosylated yeast proteins were isolated that supported 2G12 binding. Removal of high-mannose-type N-linked carbohydrates from the proteins resulted in loss of 2G12 recognition. Sera from rabbits immunized with TM yeast cells contained Abs that could cross-react with HIV-1 gp120 and that recognized a variety of clade B, C and SIV gp120 proteins. Like 2G12, binding of these Abs to Env proteins was abrogated by removal of N-linked high mannose glycans. The elicited Abs had 50-100-fold lower gp120 binding activity than 2G12, and the antiserum recognized a larger variety of mannose-dependent epitopes. There was no observed neutralizing activity of the sera. The results indicate that immunizations with TM yeast can elicit 2G12-like Abs. Luallen2008 (vaccine antigen design)
2G12: A mathematical model was developed and used to derive transmitted or founder Env sequences from individuals with acute HIV-1 subtype B infection. All of the transmitted or early founder Envs were sensitive to neutralization by 2G12. Keele2008 (neutralization, acute/early infection)
2G12: This review summarizes the obstacles that stand in the way of making a successful preventive HIV-1 vaccine, such as masked or transiently expressed Ab epitopes, polyclonal B-cell class switching, and inefficient, late, and not sufficiently robust mucosal IgA and IgG responses. Possible reasons why HIV-1 envelope constructs expressing 2G12 epitope fail to induce broadly neutralizing Abs are discussed. Haynes2008 (vaccine antigen design, review)
2G12: Transmission of HIV-1 by immature and mature DCs to CD4+ T lymphocytes was significantly higher for CXCR4- than for CCR5-tropic strains. In addition, preneutralization of X4 virus with 2G12 prior to capture efficiently blocked transmission to 36%, while transmission of R5 was blocked to 63%, indicating that 2G12 treatment results in more efficient transfer of X4 than of R5 HIV-1. vanMontfort2008 (co-receptor, neutralization, dendritic cells)
2G12: 2G12 did not neutralize a clade C SHIV strain in the TZM-bl based assay. Zhang2008 (neutralization)
2G12: Sera from both gp120 DNA prime-protein boost immunized rabbits and from protein-only immunized rabbits did not compete for binding to 2G12, indicating no elicitation of 2G12-like Abs by either of the immunization regimens. Vaine2008 (vaccine antigen design)
2G12: An R5 HIV variant, in contrast to its parental virus, was shown to infect T-cell lines expressing low levels of cell surface CCR5 and to infect cells in the absence of CD4. The variant was neutralized less efficiently by 2G12 than the parental virus, indicating conformational changes in gp120. These properties of the mutant virus were determined by alternations in gp41. Taylor2008 (co-receptor, neutralization)
2G12: In order to assess whether small molecule CCR5 inhibitor resistant viruses were more sensitive to neutralization by NAbs, two escape mutant viruses, CC101.19 and D1/85.16, were tested for their sensitivity to neutralization by 2G12, compared to the sensitivity of CC1/85 parental isolate and the CCcon.19 control isolate. The CC101.19 escape mutant has 4 sequence changes in V3 while the D1/85.16 has no sequence changes in V3 and relies on other sequence changes for its resistance. D1/85.16, but not CC101.19 escape variant, was markedly more sensitive to neutralization by 2G12 (approx. 50-fold). As 2G12 had no significantly higher affinity for gp120 from D1/85.16, the increased sensitivity of this virus is most likely due to alternation in the conformation or accessibility of the 2G12 epitope on its Env trimer. Overall, the study suggests that CCR5 inhibitor-resistant viruses are likely to be somewhat more sensitive to neutralization than their parental viruses. Pugach2008 (co-receptor, neutralization, escape, binding affinity)
2G12: The sensitivity of R5 envelopes derived from several patients and several tissue sites, including brain tissue, lymph nodes, blood, and semen, was tested against a range of inhibitors and Abs targeting CD4, CCR5, and various sites on the HIV envelope. All but one envelopes from brain tissue were macrophage-tropic while none of the envelopes from the lymph nodes were macrophage-tropic. Macrophage-tropic envelopes were also less frequent in blood and semen. There was a clear variation in sensitivity to 2G12, where most envelopes were sensitive, while some were resistant to neutralization by this Ab. There was a significant correlation between increased envelope macrophage-tropism and decreased 2G12 sensitivity. It is suggested that the macrophage-tropic brain variants are less protected by glycosylation due to absence of Abs in the brain, thus lacking N-glycosylation sites critical for 2G12 neutralization. Three of nine brain envelopes were resistant to 2G12, while only one of nine lymph node envelopes were resistant to 2G12. Peters2008a (antibody binding site, neutralization)
2G12: To examine sequence and conformational differences between subtypes B and C, several experiments were performed with 11 MAbs regarding binding and neutralization. Both binding and neutralization studies revealed that the 11 MAbs could be divided in three different groups, and that the most differences between the subtypes were located in the stem and turn regions of V3. 2G12 was used as control in neutralization assays, and was able to neutralize JR-FL and SF162 isolates, as well as a chimeric SF162 variant with a JR-FL-like V3 sequence. Patel2008 (neutralization)
2G12: Contemporaneous biological clones of HIV-1 were isolated from plasma of chronically infected patients and tested for their functional properties. The clones showed striking functional diversity both within and among patients, including differences in infectivity and sensitivity to inhibition by 2G12. There was no correlation between clonal virus infectivity and sensitivity to 2G12 inhibition, indicating that these properties are dissociable. The sensitivity to 2G12 inhibition was, however, a property shared by viruses from a given patient, suggesting that the genetic determinants that define this sensitivity may lie in regions that are not necessarily subject to extensive diversity. Nora2008 (neutralization)
2G12: A peptide 2G12.1, that binds to 2G12, was derived by screening of phage-displayed peptide libraries with 2G12. Comparison of the crystal structure of the Fab 2G12 bound to 2G12.1 peptide, and 2G12 bound to carbohydrate, revealed that 2G12 binding to peptide and carbohydrate occurs through different Ab interactions. The 2G12.1 peptide occupied a site different from, but adjacent to, the primary carbohydrate binding site on 2G12. Thus, this does not support structural mimicry of the peptide to the native carbohydrate epitope on gp120. In addition, the 2G12.1 peptide was not an immunogenic mimic of the 2G12 epitope either, since the sera from mice immunized with the peptide did not bind gp120. Menendez2008 (mimics, structure)
2G12: Maize was evaluated as a potential inexpensive large-scale production system for therapeutic antibodies against HIV. 2G12 was expressed in maize endosperm. In vitro cell assays demonstrated that the HIV-neutralizing properties of the maize-produced 2G12 MAb were equivalent to those of Chinese hamster ovary cell-derived MAb 2G12. Rademacher2008
2G12: Neutralization susceptibility of CRF01_AE Env-recombinant viruses, derived from blood samples of Thai HIV-1 infected patients in 2006, was tested to 2G12. Most of the 35 viruses tested replicated efficiently in the presence of 2G12, in spite of highly conserved PNLG sites recognized by this Ab, indicating that CRF01_AE is not susceptible to neutralization by 2G12. These results suggest that the protein structure , including conformation of the CD4 binding domain, may somehow be different between CRF01_AE and subtype B Env gp120. Utachee2009 (neutralization)
2G12: Concentrations of neutralizing Abs in long-term non-progressors (LNTPs) were significantly higher than the concentrations in asymptomatic subjects and subjects with AIDS, with no statistically significant difference between the two latter groups. Amino acid substitutions in the 2G12 epitope were found in both asymptomatic subjects and subjects with AIDS, while no such mutations were found among LNTPs. Eight different mutations were found at five N-glycosylation linked sites: 295V/T/D/K, 297I, 332E. 334N, and 386D. The mutation rates of the conserved 2G12 neutralization epitopes were significantly different among LNTPs, asymptomatic patients, and patients with AIDS. Wang2008 (escape, rate of progression)
2G12: Synergy of 2F5 with MAbs 2G12, D5, and peptide C34 was examined. 2G12 exhibited synergy in inhibition of HIV-1 89.6 with MAb 2F5. 2G12 was not as synergistic when combined with D5 as 2F5 was. Hrin2008 (antibody interactions)
2G12: A series of peptide conjugates were constructed via click reaction of both aryl and alkyl acetylenes with an internally incorporated azidoproline 6 derived from parent peptide RINNIPWSEAMM. Many of these conjugates exhibited increase in both affinity for gp120 and inhibition potencies at both the CD4 and coreceptor binding sites. None of the high affinity peptides inhibited the interactions of YU2 gp120 with 2G12 Ab. The aromatic, hydrophobic, and steric features in the residue 6 side-chain were found important for the increased affinity and inhibition of the high-affinity peptides. Gopi2008
2G12: Three constructs of the outer domain (OD) of gp120 of subtype C, fused with Fc, were generated for immunization of mice: OD(DL3)-Fc (has 29 residues from the center of the V3 loop removed), OD(2F5)-Fc (has the same deletion reconstructed to contain the sequence of 2F5 epitope), and the parental OD-Fc molecule. All OD variants contained substitutions at residues 295 and 394 that reintroduced the 2G12 epitope into the used sequence. All three OD-variants reacted with 2G12, indicating that the isolated outer domain is conformationally immobile. Despite the presence of the 2G12 epitope, none of the sera from mice immunized with the three OD-constructs showed 2G12-like reactivity. Chen2008a (vaccine antigen design)
2G12: The goal of the study was to measure NAb responses in patients infected with HIV-1 prevalent subtypes in China. g160 genes from plasma samples were used to establish a pseudovirus-based neutralization assay. 2G12 neutralized 33% of subtype B clones but not subtype BC and AE clones. Chong2008 (neutralization, subtype comparisons)
2G12: To investigate B-cell responses immediately following HIV-1 transmission, Env-specific Ab responses to autologous and consensus Envs in plasma donors were determined. Broadly neutralizing Abs with specificity similar to 2G12 did not appear during the first 40 days after plasma virus detection. Tomaras2008 (acute/early infection)
2G12: The neutralization profile of early R5, intermediate R5X4, and late X4 viruses from a rhesus macaque infected with SHIV-SF162P3N was assessed. 2G12 neutralized all three viruses with similar low potency. Tasca2008 (co-receptor, neutralization)
C2G12: Neutralization of HIV-1 IIIB LAV isolate by 2G12 was within the same range as the neutralization of the virus by natural antibodies from human sera against the gal(α1,3)gal disaccaride linked to CD4 gp120-binding peptides, indicating that the activity of natural antibodies can be re-directed to neutralize HIV-1. Perdomo2008 (neutralization)
2G12: A new purification method was developed using a high affinity peptide mimicking CD4 as a ligand in affinity chromatography. This allowed the separation in one step of HIV envelope monomer from cell supernatant and capture of pre-purified trimer. Binding of 2G12 to gp120SF162 purified by the miniCD4 affinity chromatography and a multi-step method was comparable, suggesting that the miniCD4 allows the separation of HIV-1 envelope with intact 2G12 epitope. gp140DF162ΔV2 was purified by the miniCD4 method to assess its ability to capture gp140 trimers. Binding of 2G12 to gp140DF162ΔV2 purified by the miniCD4 affinity chromatography and a multi-step method was comparable, suggesting that the SF162 trimer antigenicity was preserved. Martin2008 (assay or method development, binding affinity)
2G12: A divalent Man9ClcNAc2 glycopeptide, that binds to 2G12, was covalently coupled to the OMPC carrier and used as immunogen to test its efficacy to induce 2G12-like neutralizing Ab response. High levels of carbohydrate-specific Ab were induced in both guinea pigs and rhesus macaques, but these Ab showed poor recognition of recombinant gp160 and failed to neutralize a panel of subtype B isolates. Sera from HIV-1 positive individuals was tested for binding to the synthetic antigen but failed to recognize the mimetics, although two of the patients showed presence of 2G12-like Abs. These results suggest that presentation of Man9ClcNAc2 on the constrained cyclic scaffold is insufficient to induce a polyclonal response that recognizes native 2G12 epitope. Joyce2008 (mimotopes, neutralization, vaccine antigen design)
2G12: MAb 2G12 binds to gp120 and is essentially inactive after CD4 engagement, with a neutralization half-life of less than 1 minute. Thus, the binding site for 2G12 on gp120 is unavailable once the CD4-induced conformational changes in gp120 have occurred. Gustchina2008 (antibody binding site, neutralization, kinetics)
2G12: Variable domains of three heavy chain Abs, the VHH, were characterized. The Abs were isolated from llamas, who produce immunoglobulins devoid of light chains, immunized with HIV-1 CRF07_BC, to gp120. It was hypothesized that the small size of the VHH, in combination with their protruding CDR3 loops, and their preference for cleft recognition and binding into active sites, may allow for recognition of conserved motifs on gp120 that are occluded from conventional Abs. 2G12 provided some inhibition of binding of the three neutralizing VHH Abs to gp120, suggesting that 2G12 imposes steric hinderance to binding of the VHH Abs to gp120. Forsman2008 (antibody interactions)
2G12: 24 broadly neutralizing plasmas from HIV-1 subtype B and C infected individuals were investigated using a series of mapping methods to identify viral epitopes targeted by NAbs. In competitive virus capture assays on 2G12 coated plates, some of the subtype B plasmas, and two of the subtype C plasmas, inhibited virus capture. Mutant versions of JR-FL trimers were designed to selectively eliminate neutralization epitopes, but the plasma titers against the 2G12-eliminated mutant were similar to those against the wildtype. This indicated that very few, if any, 2G12-like Abs were present in the plasmas, and that a fraction of patients developed Abs that overlap the 2G12 epitope but do not neutralize the virus. Binley2008 (neutralization, binding affinity)
2G12: 32 human HIV-1 positive sera neutralized most viruses from clades A, B, and C. Two of the sera stood out as particularly potent and broadly reactive. Two CD4-binding site defective mutant Env proteins were generated to evaluate whether Abs to the CD4-binding site are involved in the neutralizing activity of the two sera. The integrity of the wildtype and mutant proteins was tested for their reactivity to 2G12. Li2007a (binding affinity)
2G12: A recombinant gp120-Fc bound to 2G12, indicating it was conformationally intact. 2G12 binding to gp120 was inhibited by the soluble recombinant extracellular domain (ECD) of DC-SIGN in a dose-dependent fashion, but 2G12 did not inhibit binding of gp120 to DC-SIGN. Many single, double, and triple N-glycan mutations in the 2G12 epitope did not affect binding of gp120 to DC-SIGN, however, some of the N-glycan sites within the 2G12 epitope were shown to be optimally positioned to significantly contribute to DC-SIGN binding. Thus, it is suggested that DC-SIGN can bind to a flexible combination of N-glycans on gp120, both within and outside of the 2G12 epitope, but that its optimal binding site overlaps with specific N-glycans within the 2G12 epitope. Hong2007 (binding affinity)
2G12: HIV-1 env clones resistant to cyanovirin (CV-N), a carbohydrate binding agent, showed amino acid changes that resulted in deglycosylation of high-mannose type residues in the C2-C4 region of gp120. Compared to their parental virus HIV-1 IIIB, these CV-N resistant viruses were also completely resistant to 2G12, as they lost one or more 2G12 binding glycans on gp120. Hu2007 (neutralization, escape)
2G12: Chemical inhibition of mammalian glycoprotein synthesis with the plant alkaloid kifunensine resulted in an abundance of oligomannose-type glycans on the cell surface, and binding of 2G12 to previously non-antigenic self proteins and cells. Expression of gp120 in the presence of kifunensine also increased both binding and valency of gp120 to 2G12. Scanlan2007 (antibody binding site, binding affinity)
2G12: The ability of 2G12 to neutralize recently transmitted viruses was examined in four homosexual and two parenteral transmission couples. The vast majority of recently transmitted viruses from homosexual recipients were resistant to neutralization by 2G12, although viruses isolated later in the course of infection showed increased sensitivity to 2G12 in one of the patients. In the parenteral transmission, one of the recipients had early viruses resistant to 2G12 neutralization, and one had viruses somewhat sensitive to 2G12 neutralization. The neutralization sensitivity patterns of recipient viruses to 2G12 did not correlate to the neutralization sensitivity patterns of their donors in the homosexual couples, while the HIV-1 variants from the one of the two parenteral pairs were similarly resistant to neutralization by 2G12. 12% of 2G12 resistant viruses had all five PNGS of the 2G12 epitope. 88.5% of the 2G12 resistant viruses lacked at least one of the five PNGS, and viruses isolated later in infection that had become sensitive to 2G12 neutralization had restored the 2G12 epitope. Quakkelaar2007a (neutralization, acute/early infection, mother-to-infant transmission)
2G12: Three MAbs, 2G12, 4E10 and 2F5, were administered to ten HIV-1 infected individuals treated with ART during acute and early infection, in order to prevent viral rebound after interruption of ART. MAb infusions were well tolerated with essentially no toxicity. Viral rebound was not prevented, but was significantly delayed in 8/10 patients. 2G12 activity was dominant among the MAbs used. Baseline susceptibility to 2G12 was inversely correlated with the time to viral rebound. Escape from 2G12 was associated with viral rebound. Long-term suppression of viremia was achieved in 3/10 patients. Mehandru2007 (escape, immunotherapy, supervised treatment interruptions (STI))
2G12: MBL, a lectin present in human serum that recognizes mannose-rich N-glycans, was shown to mediate increased HIV-1 infectivity, and to reduce 2G12-mediated neutralization of HIV-1. Marzi2007 (neutralization)
2G12: The study compared Ab neutralization against the JR-FL primary isolate and trimer binding affinities judged by native PAGE. There was direct quantitative relationship between monovalent Fab-trimer binding and neutralization, implying that neutralization begins as each trimer is occupied by one Ab. In BN-PAGE, neutralizing Fabs, 2G12 in particular, and sCD4 were able to shift JR-FL trimers. In contrast, most non-neutralizing Fabs bound to monomer, but their epitopes were conformationally occluded on trimers, confirming the exclusive relationship of trimer binding and neutralization. For 2G12, there was a ladder of partially and fully liganded trimers Crooks2008 (neutralization, binding affinity)
2G12: Five amino acids in the gp41 N-terminal region that promote gp140 trimerization (I535, Q543, S553, K567 and R588) were considered. Their influence on the function and antigenic properties of JR-FL Env expressed on the surfaces of pseudoviruses and Env-transfected cells was studied. Various non-neutralizing antibodies bind less strongly to the Env mutant, but neutralizing antibody binding is unaffected. There was no difference in 2G12 binding to wild type and mutant JR-FL, and 2G12 inhibited infection of the two pseudoviruses with comparable potencies. Dey2008 (binding affinity)
2G12: The study explores how the V1 loop of Env influences the neutralization susceptibilities of heterologous viruses to antibodies elicited by the SF162gp140 immunogen. All viruses expressing the WT Envs were susceptible to neutralization by 2G12. Replacement of the V1 loops by that of SF162 did not alter the neutralization susceptibilities of the viruses. Ching2008 (neutralization)
2G12: Molecular mechanism of neutralization by MPER antibodies, 2F5 and 4E10, was studied using preparations of trimeric HIV-1 Env protein in the prefusion, the prehairpin intermediate and postfusion conformations. MAb 2G12 was used to analyze antigenic properties of construct 92UG-gp140-Fd, derived from isolate 92UG037.8 and stabilized by a C-terminal foldon tag. 92UG-gp140-Fd binds 2G12 with high affinity. Frey2008 (binding affinity)
2G12: The study explores the development of a carbohydrate immunogen that could elicit 2G12-like neutralizing ABs to contribute to an AIDS vaccine. Specifically, the study describes the development of neoglycoconjugates displaying variable copy numbers of synthetic tetramannoside (Man(4) on bovine serum albumin (BSA) molecules by conjugation to Lys residues. Immunization of rabbits with BSA-(Man(4))(14) elicits significant serum Ab titers to Man(4). However, these Abs are unable to bind gp120. Astronomo2008 (vaccine antigen design)
2G12: Addition of a glycosylation site at position V295N in three different subtype C envelope clones (COT9.6, COT6.15 and Du151.2) resulted in increase in binding of 2G12. However, only one of the viral clones (COT9.6) became sensitive to neutralization by 2G12 at high Ab concentrations. Introduction of glycosylation site at position 448 in COT6.15 further increased its binding to 2G12 and resulted in viruses more sensitive to neutralization. Furthermore, addition of glycosylation at position 442 increased binding and neutralization sensitivity of the corresponding viruses to 2G12, and deletion of glycosylation at position 386 resulted in reduction in binding and resistance to neutralization by 2G12. Gray2007a (antibody binding site, neutralization, binding affinity, subtype comparisons)
2G12: A D386N change in the V4 region, which results in restoration of N-glycosylation at this site, did not have any impact on the neutralization of a mutant virus by 2G12 compared to wildtype. Also, there was no association between increased sensitivity to 2G12 neutralization and enhanced macrophage tropism. Dunfee2007 (antibody binding site)
2G12: This review summarizes data on the development of HIV-1 centralized genes (consensus and ancestral) for induction of neutralizing antibody responses. Functionality and conformation of native epitopes in proteins based on the centralized genes was tested and confirmed by binding to 2G12 and other MAbs. Antibodies induced by immunization with these centralized proteins did not, however, have the breadth and potency compared to that of 2G12 and other broadly neutralizing MAbs. Gao2007 (antibody binding site, neutralization, vaccine antigen design, review)
2G12: Macaques were immunized with either CD4, gp120, cross-linked gp120-human CD4 complex (gp120-CD4 XL), and with single chain complex containing gp120 rhesus macaque CD4 domains 1 and 2 (rhFLSC). Sera from the rhFLSC immunized animals showed slightly higher competition titers, being able to block gp120-CD4 complex interactions with 2G12 slightly more efficiently than sera from animals immunized with the three other proteins. DeVico2007 (neutralization)
2G12: 2G12-blocking activity was very low in all of the sera from guinea pigs immunized with gp120 protein, or with three types of VLPs: disulfide-shackled functional trimers (SOS-VLP), uncleaved nonfunctional Env (UNC-VLP), naked VLP bearing no Env. Crooks2007 (neutralization, vaccine antigen design)
2G12: Interactions of this Ab with gp120 monomer and two cleavage-defective gp140 trimers were studied. It was shown that 2G12 interactions with the soluble monomers and trimers were minimally affected by GA cross-linking of the proteins, indicating that the 2G12 epitope was maintained after cross-linking. This Ab was associated with a small entropy change upon gp120 binding. This Ab was shown to have a kinetic advantage as it bound to gp120 faster than other less neutralizing Abs. Yuan2006 (antibody binding site, antibody interactions, kinetics, binding affinity)
2G12: No significant levels of 2G12 were shown to bind to HA/gp41 expressed on cell surfaces and this Ab did not stain cells expressing HA/gp41 in a fluorescence assay. However, it did bind to HIV 89.6 Env expressing cells. Ye2006 (antibody binding site, binding affinity)
2G12: Viruses with wild-type HIV-1JR-FL Envs were neutralized by this Ab at much lower concentrations than HIV-1 YU2 Env viruses. Yang2006 (neutralization, binding affinity)
2G12: SHIV SF162p4 virus used as challenge in ISCOM vaccinated macaques was shown to be highly sensitive to neutralization by this Ab. Pahar2006 (neutralization)
2G12: All subtype C env-pseudotyped clones derived from individuals in acute/early stage of HIV-1 infection were highly resistant to neutralization by this Ab, since each of the clones lacked a PNLG at one or more critical epitope positions. The sensitivity of clones to a mix of Abs IgG1b12, 2G12 and 2F5 was tracked to IgG1b12. Li2006a (neutralization, variant cross-reactivity, acute/early infection, subtype comparisons)
2G12: This Ab was used as a control since its epitope is independent of either V1/V2 or V3 domains confirmed in its equal neutralization of SF162 and variants SF162(JR-FL V3), SF162(JR-FL V1/V2) and SF162(JR-FL V1/V2/V3). This Ab was also shown to neutralize viruses with V3 sequences from several different subtypes (B, F, A1, H, C, CRF02_AG and CRF01_AE). Krachmarov2006 (neutralization, variant cross-reactivity, subtype comparisons)
2G12: Binding of 2G12 to wt gp120 and two constructs with 5 and 9 residues deleted in the middle of the beta3-beta5 loop in the C2 region of gp120 was examined. The deletions of the loop residues did not affect the conformation of 2G12 epitope as 2G12 Ab binding and kinetics were identical for the wt gp120 and both constructs. Rits-Volloch2006 (antibody binding site, kinetics, binding affinity)
2G12: This Ab was used as a positive control in the neutralization assay. At the highest Ab concentrations, 2G12 was able to neutralize several primary isolates but not all, with a neutralization pattern similar to that of rabbit sera immunized with monovalent and polyvalent DNA-prime/protein-boost Env from different HIV-1 subtypes. At a reduced concentrations, 2G12 showed much weaker neutralizing activities. Wang2006 (neutralization, variant cross-reactivity, subtype comparisons)
2G12: Novel approaches based on sequential (SAP) and competitive (CAP) antigen panning methodologies, and use of antigens with increased exposure of conserved epitopes, for enhanced identification of broadly cross-reactive neutralizing Abs are reviewed. Previously known broadly neutralizing human mAbs are compared to Abs identified by these methods. Zhang2007 (review)
2G12: This Ab was used in the analysis of clade C gp140 (97CN54) antigenicity and was shown not to bind to this molecule, as the glycan epitope is absent. Sheppard2007a (binding affinity)
2G12: 2 glycosylation site additions to asparagines 295 and 392 on the clade C gp120 backbone (gp120CN54+) were used to reconstruct the 2G12 epitope, as the gp120CN54+ construct showed excellent reactivity with 2G12. gp120CN54+ and an Fc tagged outer domain of gp120 (ODCN54+-Fc) bound equally well to 2G12, while Fc fusion to gp120CN54+ reduced 2G12 binding, indicating partial occlusion of the 2G12 epitope. Chen2007a (antibody binding site, binding affinity)
2G12: Pseudoviruses derived from gp120 Env variants that evolved in multiple macaques infected with SHIV 89.6P displayed a range of degrees of virion-associated Env cleavage. Pseudoviruses with higher amount of cleaved Env were more sensitive to neutralization by 2G12, as they contained peripheral glycan N386, not present in the wildtype 89.6P. Blay2007 (neutralization)
2G12: Carbohydrate-binding agents, including 2G12, are reviewed regarding to their antiviral activity, resistance development, and their potential use as therapeutic agents. Balzarini2007 (review)
2G12: Increased neutralization sensitivity was observed for (R5)X4 viruses from timepoints both early and late after emergence of X4 compared to their coexisting R5 variants in one patient, and only for the early (R5)X4 viruses in another patient. In a third patient, in contrast, late (R5)X4 viruses were found to be significantly more resistant to 2G12 neutralization than their coexisting R5 variants. Bunnik2007 (co-receptor, neutralization)
2G12: Neutralization sensitivity of maternal and infant viruses to 2G12 close to transmission timepoint was shown to be poor. Even the viruses from one mother, that were shown to be sensitive to maternal Abs and pooled plasma, were not neutralized by 2G12, indicating that Abs in plasma are not directed to this Ab epitope. Rainwater2007 (neutralization, mother-to-infant transmission)
2G12: 2G12-neutralized HIV-1 captured on Raji-DC-SIGN cells or immature monocyte-derived DCs (iMDDCs) was successfully transferred to CD4+ T lymphocytes, indicating that the 2G12-HIV-1 complex was disassembled upon capture by DC-SIGN-cells. vanMontfort2007 (neutralization, dendritic cells)
2G12: Synthetic monomeric D1 arm oligosaccharide, corresponding to the D1 arm of Man9 which has a high affinity to 2G12, and its fluorinated derivative interacted with 2G12 only weakly. However, when four units of synthetic D1 arm tetrasaccharide were introduced to a cyclic decapeptide template, it showed high affinity to 2G12. Introduction of two T-helper epitopes onto the template did not affect 2G12 binding, indicating that the construct could be used as a new type of immunogen for raising carbohydrate-specific neutralizing Abs against HIV. Wang2007b (mimotopes, vaccine antigen design, kinetics, binding affinity)
2G12: Infusion of a MAb cocktail (4E10, 2G12 and 2F5) into HIV-1 infected subjects was shown to be associated with increased levels of serum anti-cardiolipin and anti-phosphatidylserine Ab titers, and increased coagulation times. In the absence or in the presence of adult and neonate plasma, 2G12 did not bind to either phosphatidylserine nor to cardiolipin, and did not induce significant prolongations of clotting times in human plasma, indicating that infusion of 2G12 was not responsible for autoreactivity and prolonged clotting times. Vcelar2007 (antibody interactions, autoantibody or autoimmunity, binding affinity, immunotherapy)
2G12: The major infectivity and neutralization differences between a PBMC-derived HIV-1 W61D strain and its T-cell line adapted counterpart were conferred by the interactions of three Env amino acid substitutions, E440G, D457G and H564N. Chimeric Env-pseudotyped virus Ch5, containing all three of the mutations, was equally neutralization sensitive to 2G12 as Ch2, which did not contain any of these mutations. Beddows2005a (neutralization)
2G12: Four primary isolates (PIs), Bx08, Bx17, 11105C and Kon, were tested for binding and neutralization by 2G12. 2G12 was only able to neutralize Bx08, but bound well to both Bx08 and Bx17 and less well to 11105C and Kon. There was no direct correlation between binding and neutralization of the four PIs by 2G12. CD4-induced gp120 shedding resulted in a decrease of 2G12 binding to Bx08. Presence of gp160 depleted of the principal immunodominant domain (PID) significantly decreased capture of Bx17 and Kon by 2G12. Presence of both gp160ΔPID and PID slightly improved the inhibition of virus capture compared to PID peptide alone, revealing an additive effect. Burrer2005 (neutralization, binding affinity)
2G12: A panel of 60 HIV-1 isolates, with complete genome sequences available, was formed for neutralization assay standardization. It comprises of 10 isolates from each of the subtypes A, B, C, D, CRF01_AE and CRF02AG, with majority of the viruses being of R5 phenotype and few of X4 phenotype. Neutralization profile of each isolate was assessed by measuring neutralization by sCD4, a cocktail of MAbs including 2G12, 2F5 and IgG1b12, and a large pool of sera collected from HIV-1 positive patients. The MAb cocktail neutralized with >50% a large portion of the isolates (51/60) including: 10 subtype A isolates, 8 subtype B isolates, 8 subtype C isolates, 9 subtype D isolates, 7 CRF-01_AE isolates, and 9 CRF_02AG isolates. Brown2005a (assay or method development, neutralization, subtype comparisons)
2G12: The unique structure of the 2G12 MAb, and the reasons for its unique ability to recognize oligomannose chains on the silent face of the gp120, are reviewed. Engineering of Abs based on revealed structures of broadly neutralizing MAbs is discussed. Burton2005 (antibody binding site, review, structure)
2G12: SFV-gp140(-GCN4) was constructed for analysis of its immunogenic properties in animal models. Both gp120 and gp140(-GCN4) secreted from rSFV-infected cells were recognized by 2G12, suggesting that the proteins retained their native folding. Forsell2005 (antibody binding site)
2G12: Monomeric gp120 and trimeric gp140CF proteins synthesized from an artificial group M consensus Env gene (CON6) bound efficiently to 2G12, indicating correct exposure of the 2G12 epitope. A mix of 2G12, 2F5 and b12 MAbs (TriMab2) was used for neutralization assessment of some subtype B isolates, but showed no significant neutralization. Gao2005a (antibody binding site, neutralization)
2G12: 2G12 neutralized viral isolates HXBc2, SF162, 89.6 and BaL. ADA isolate was poorly neutralized and the YU2 isolate was not neutralized. Neutralization was concentration dependent, as higher MAb concentration resulted in higher % of neutralization. The exception was the YU2 isolate, where higher concentration of 2G12 resulted in enhancement of viral infection. Grundner2005 (enhancing activity, neutralization)
2G12: 2G12 bound with a higher maximal mean fluorescence intensity (MFI) to Env protein on the surface of cells producing gp140Δct-pseudotyped neutralization resistant 3.2P strain, than to the Env of pseudotyped neutralization sensitive HXBc2. Neutralization assays with the pseudotyped viruses showed that 2G12 neutralized both viruses with same potency. Furin co-transfection did not have an effect on the reactivity of pseudoviruses with 2G12 or on their neutralization sensitivity. Presence or absence of sialic acid residues did not affect Env reactivity with 2G12. Herrera2005 (antibody binding site, neutralization, binding affinity)
2G12: Why broadly neutralizing Abs, such as 2G12, 2F5 and 4E10, are extremely rare, and their protective abilities and potential role in immunotherapy are discussed. Julg2005 (neutralization, immunotherapy, review)
2G12: Point mutations in the highly conserved structural motif LLP-2 within the intracytoplasmic tail of gp41 resulted in conformational alternations of both gp41 and gp120. The alternations did not affect virus CD4 binding, coreceptor binding site exposure, or infectivity of the virus, but did result in increased relative neutralization resistance of the LLP-2 mutant virus to 2G12, compared with wildtype virus. The increased neutralization resistance of LLP-2 virus was associated with decreased 2G12 binding to its epitope. Kalia2005 (antibody binding site, neutralization, binding affinity)
2G12: A series of genetically modified Env proteins were generated and expressed in both insect and animal cells to be monitored for their antigenic characteristics. For 2G12, two of the modified proteins expressed in insect cells, dV1V2 mutant (V1V2 deletions) followed by the dV2 mutant, showed higher binding to the Ab than the wildtype Env did, indicating that V1V2 deletion exposes epitopes against 2G12 better than other proteins. Unlike for most of the other MAbs, 3G mutant (mutations in 3 glycosylation sites) did not show a higher binding affinity to 2G12. When expressed in animal cells, only dV2 mutant resulted in higher binding to 2G12, while all other modified proteins showed lower binding compared to the wildtype. Kang2005 (antibody binding site, binding affinity)
2G12: Full-length gp160 clones were derived from acute and early human HIV-1 infections and used as env-pseudotyped viruses in neutralization assays for their characterization as neutralization reference agents. 12 out of 19 pseudoviruses were neutralized by 2G12, as were SF162.LS and IIIB strains but not the MN strain. Resistance to 2G12 was generally associated with lack of N-glycosylation sites, except in one case, where the clone was resistant to neutralization in spite of presence N-glycosylation sites. Two clones lacked N-glycosylation at residues 339 and 386, but remained sensitive to 2G12. A mixture of IgG1b12, 2F5 and 2G12 (TriMab) exhibited potent neutralizing activity against all Env-pseudotyped viruses except one. 7 out of 12 Env-pseudotyped viruses were more sensitive to neutralization by 2G12 than their uncloned parental PBMC-grown viruses. Li2005a (assay or method development, neutralization)
2G12: Pseudoviruses expressing HIV-1 envelope glycoproteins from BL01, BR07 and 89.6 strains were compared in neutralization assays to replication competent clone derived from transfection of 293T cells (IMC-293T) and to the IMC-293T derived from a single passage through PBMC (IMC-PBMC). The neutralization responses of pseudoviruses and corresponding IMC-293T to 2G12 were similar, while a significant decrease in viral neutralization sensitivity to 2G12 was observed for all three IMC-PBMC viruses. The decrease was associated with an increase in average virion envelope glycoprotein content on the PBMC-derived virus. Louder2005 (assay or method development, neutralization)
2G12: 2G12 was used as isolating template for screening of a phage library in order to develop mimotopes that target carbohydrate antigens of gp120. Specific binding of 2G12 to three phages expressing peptides was observed, however, 2G12 did not bind to the peptides themselves. Pashov2005a (assay or method development)
2G12: 2G12 neutralized JR-FL, but not YU2 HIV-1 strain. 2G12 and other neutralizing mAbs recognized JR-FL cleavage-competent and cleavage-defective env glycoproteins, while non-neutralizing Abs only recognized JR-FL cleavage-defective glycoproteins. It is suggested that an inefficient env glycoprotein precursor cleavage exposes non-neutralizing determinants, while only neutralizing regions remain accessible on efficiently cleaved spikes. For YU2, both cleavage-competent and -defective glycoproteins were recognized by both neutralizing and non-neutralizing Abs. Pancera2005 (antibody binding site, neutralization, binding affinity)
2G12: A short review of 2F5 and 4E10 interaction with autoantigens, epitope accessibility, structure, neutralizing capability, and the reasons for their infrequent appearance in nature. Immunotherapy and escape to 2G12 is also discussed. Nabel2005 (escape, immunotherapy, review)
2G12: Viruses containing substitutions at either L568 or K574 of the gp41 hydrophobic pocket were resistant to D5-IgG1 but were as sensitive to 2G12 as the wildtype virus. Miller2005
2G12: This short review summarizes recent findings of the role of neutralizing Abs in controlling HIV-1 infection. Certain neutralizing MAbs and their potential role in immunotherapy and vaccination, as well as the reasons for their poor immunogenicity, are discussed. Montefiori2005 (antibody binding site, therapeutic vaccine, escape, immunotherapy)
2G12: Virions containing a single point mutation Y706C in gp41 had a 10-fold increase in binding to 2G12 compared to wildtype. This, together with the same p24 supernatant levels after transfection with wildtype and mutant virus, indicated that the mutant virions contained more envelope on a per-particle basis. Poon2005 (antibody binding site, binding affinity)
2G12: Escape mutations in HR1 of gp41 that confer resistance to Enfuvirtide reduced infection and fusion efficiency and also delayed fusion kinetics of HIV-1. They also conferred increased neutralization sensitivity to a subset of neutralizing MAbs that target fusion intermediates or with epitopes exposed following receptor interactions. Enhanced neutralization correlated with reduced fusion kinetics. None of the mutations had a significant effect on 2G12 neutralization of virus. Reeves2005 (antibody binding site, drug resistance, neutralization, escape, HAART, ART)
2G12: There was no difference found in the neutralization sensitivity of viruses isolated from acutely and from chronically infected HIV-1 patients to this Ab, suggesting that the glycosylation sites manifesting the epitope of 2G12 are well conserved throughout the course of infection. Rusert2005 (antibody binding site, neutralization, acute/early infection)
2G12: This review summarizes data on the role of NAb in HIV-1 infection and the mechanisms of Ab protection, data on challenges and strategies to design better immunogens that may induce protective Ab responses, and data on structure and importance of MAb epitopes targeted for immune intervention. The importance of standardized assays and standardized virus panels in neutralization and vaccine studies is also discussed. Srivastava2005 (antibody binding site, neutralization, vaccine antigen design, binding affinity, immunotherapy, review, structure)
2G12: Six acutely and eight chronically infected patients were passively immunized with a mix of 2G12, 2F5 and 4E10 neutralizing Abs during treatment interruption. Two chronically and four acutely infected individuals showed evidence of a delay in viral rebound during Ab treatment suggesting that NAbs can contain viremia in HIV-1 infected individuals. All subjects with virus sensitive to 2G12 developed Ab escape mutants resulting in loss of viremia and failure to treatment. In several cases resistance to 2G12 emerged rapidly. Plasma levels of 2G12 were substantially higher than those of 2F5 and 4E10, and the 2G12 levels exceeded the in vitro required 90% inhibitory doses by two orders of magnitude in subjects that responded to Ab treatment. This suggested that high levels of NAbs are required for inhibition in vivo. Trkola2005 (neutralization, acute/early infection, escape, immunotherapy, early treatment, HAART, ART, supervised treatment interruptions (STI))
2G12: Ab neutralization of viruses with mixtures of neutralization-sensitive and neutralization-resistant envelope glycoproteins was measured. It was concluded that binding of a single Ab molecule is sufficient to inactivate function of an HIV-1 glycoprotein trimer. The inhibitory effect of the Ab was similar for neutralization-resistant and -sensitive viruses indicating that the major determinant of neutralization potency of an Ab is the efficiency with which it binds to the trimer. It was also indicated that each functional trimer on the virus surface supports HIV-1 entry independently, meaning that every trimer on the viral surface must be bound by an Ab for neutralization of the virus to be achieved. Yang2005b (neutralization)
2G12: A substantial fraction of soluble envelope glycoprotein trimers contained inter-subunit disulfide bonds. Reduction of these disulfide bonds had little effect on binding of the 2G12 to the glycoprotein, indicating that the inter-S-S bonds had no impact on the exposure of 2G12 epitope. Yuan2005 (antibody binding site)
2G12: This review focuses on the importance of neutralizing Abs in protecting against HIV-1 infection, including mechanisms of Ab interference with the viral lifecycle, Ab responses elicited during natural HIV infection, and use of monoclonal and polyclonal Abs in passive immunization. In addition, vaccine design strategies for eliciting of protective broadly neutralizing Abs are discussed. MAbs included in this review are: 2F5, Clone 3 (CL3), 4E10, Z13, IgG1b12, 2G12, m14, 447-52D, 17b, X5, m16, 47e, 412d, E51, CM51, F105, F425, 19b, 2182, DO142-10, 697-D, 448D, 15e and Cβ1. McCann2005 (antibody binding site, antibody interactions, neutralization, vaccine antigen design, variant cross-reactivity, immunotherapy, review, structure)
2G12: 2G12 was investigated in different neutralization formats, including the standard format that measures activity over the entire infection period and several formats that emphasize various stages of infection. The activity of 2G12 was induced in the post-CD4 format and was less pronounced in the standard format. 2G12 did not neutralize after CD4/CCR5 engagement. HIV-1+ human plasma mediated high-levels of post-CD4 neutralization indicating presence of b12 and 2G12 -like Abs. Crooks2005 (antibody binding site, assay or method development, neutralization)
2G12: This review summarizes data on the polyspecific reactivities to host antigens by the broadly neutralizing MAbs IgG1b12, 2G12, 2F5 and 4E10. It also hypothesizes that some broadly reactive Abs might not be routinely made because they are derived from B cell populations that frequently make polyspecific Abs and are thus subjected to B cell negative selection. Haynes2005a (antibody interactions, review)
2G12: This review summarizes data that indicate that the V3 region of HIV-1 may be an epitope to target for the induction of protective Abs. Data shows that the V3 region can induce broadly-reactive, cross-neutralizing Abs, that it is partially exposed during various stages of the infectious process, and that it is immunogenic. 2G12 is the only highly neutralizing MAb targeting the carbohydrate region of gp120, suggesting that this region does not induce protective Abs. The carbohydrate epitope is poorly immunogenic and 2G12 has an aberrant structure probably extremely rare in the human Ab repertoire. Zolla-Pazner2005 (antibody binding site, variant cross-reactivity, review)
2G12: In addition to gp120-gp41 trimers, HIV-1 particles were shown to bear nonfunctional gp120-gp41 monomers and gp120-depleted gp41 stumps on their surface. 2G12 effectively neutralized wildype virus particles. 2G12 was found to bind to both nonfunctional monomers and to gp120-gp41 trimers. Binding of 2G12 to trimers correlated with its neutralization of wildtype virus particles. Monomer binding did not correlate with neutralization, but it did correlate with virus capture. It is hypothesized that the nonfunctional monomers on the HIV-1 surface serve to divert the Ab response, helping the virus to avoid neutralization. Moore2006 (antibody binding site, neutralization, binding affinity)
2G12: A carbohydrate mimetic peptide with central motif versions RYRY and YPYRY was shown to precipitate human IgG Ab that bind to gp120 and to immunoprecipitate gp120 from transfected cells. 2G12 showed significant binding only to the PYPY motif version of the peptide. Pashov2006 (mimotopes)
Macaques were immunized with SF162gp140, ΔV2gp140, ΔV2ΔV3gp140 and ΔV3gp140 constructs and their antibody responses were compared to the broadly reactive NAb responses in a macaque infected with SHIV SF162P4, and with pooled sera from humans infected with heterologous HIV-1 isolates (HIVIG). 2G12 recognized all four gp140 proteins equally. Low titers of Abs capable of blocking the binding of 2G12 were present in the sera from the SHIV-infected macaque, but were absent in the sera from the gp140-immunized animals. Derby2006 (antibody binding site)
2G12: Development of neutralizing Abs and changes to Env gp120 were analyzed in SHIV infected macaques during a period of 1 year. 4 macaques showed little viral divergence while the remaining 7 showed significant env divergence from the inoculum, associated with higher titers of homologous NAbs. In five of the 7 divergent animals, the glycosylation site N386, which is a part of the 2G12 epitope, was significantly added. Glycosylation sites N392, on the inner domain of gp120, and N295, on the silent face, also forma a part of the 2G12 epitope, and were found to be highly conserved. Blay2006 (antibody binding site)
2G12: 2G12 did not inhibit binding of Fc-gp120 to CD4, however, it inhibited binding of Fc-gp120, and of the virus itself, to the CCR5 coreceptor and to the DC-SIGN. Thus 2G12 probably inhibits HIV-1 by two mechanisms: blocking of gp120-CCR5 and of gp120-DC-SIGN interactions. Pre-incubation of virus with sCD4 did not affect its neutralization by 2G12. This Ab was also shown to effectively inhibit trans-infection of virus from primary monocyte-derived dendritic cells (MDDCs) to CD4+ T-cells. Attachment of Fc-gp120 to MDDCs and PBLs was partially inhibited by 2G12, while b12 and sCD4 did not inhibit binding to MDDCs but did inhibit binding to PBLs. The results indicate that Env attachment is mediated through DC-SIGN and other receptors on MDDCs while it is predominantly mediated by CD4 and CCR5 on PBLs. Binley2006 (antibody binding site, co-receptor, neutralization, binding affinity, dendritic cells)
2G12: A fusion protein (FLSC R/T-IgG1) that targets CCR5 was expressed from a synthetic gene linking a single chain gp120-CD4 complex containing an R5 gp120 sequence with the hinge-Ch2-Ch3 portion of human IgG1. The fusion protein did not activate the co-receptor by binding. In cell-line based assays, the FLSC R/T-IgG1 was less potent in neutralizing R5 HIV-1 primary isolates than 2G12, while in PBMC assays they were comparable. Vu2006 (neutralization)
2G12: Env-pseudotyped viruses were constructed from the gp160 envelope genes from seven children infected with subtype C HIV-1. 2G12 failed to neutralize any of the seven viruses, correlating with the absence of crucial N-linked glycans that define 2G12 epitope on these viruses. When this Ab was mixed with IgG1b12 and 2F5, the neutralization was similar as to IgGb12 alone, indicating that the majority of the pool activity was due to IgG1b12. When 4E10 was added to this mix, all isolates were neutralized. Gray2006 (neutralization, variant cross-reactivity, responses in children, mother-to-infant transmission)
2G12: Pharmacokinetic properties of this Ab were studied in HIV infected patients infused with high doses of 2G12. The Ab did not elicit an endogenous immune response and had distribution and systemic clearance values similar to other Abs. The elimination half-life was measured to 21.8 days, which is significantly longer than the elimination half-life of 4E10 and 2F5. Joos2006 (kinetics, immunotherapy)
2G12: Inhibition of 2G12 binding to gp120 by 2G12-like Abs in sera from long-term non-progressors (LTNP) was determined. 2G12-like Abs were present in almost all sera from LTNPs but at a lower levels than b12. Higher 2G12-like Ab levels were significantly associated with the broadest neutralizing activity in sera from LNTPs. Braibant2006 (enhancing activity, neutralization, variant cross-reactivity, subtype comparisons)
2G12: Neutralization rates and rate constants for the neutralization of clade B primary isolates SF33, SF162 and 89.6 by this Ab were determined. Statistically significant neutralization was not observed for isolate SF162. It was shown that neutralization sensitivity is not associated with neutralization of cell-associated or free virus. Davis2006 (neutralization, variant cross-reactivity, kinetics)
2G12: Cloned Envs (clades A, B, C, D, F1, CRF01_AE, CRF02_AG, CRF06_cpx and CRF11_cpx) derived from donors either with or without broadly cross-reactive neutralizing antibodies were shown to be of comparable susceptibility to neutralization by 2G12. Cham2006 (neutralization, variant cross-reactivity, subtype comparisons)
2G12: The ability of this Ab to inhibit viral growth was increased when macrophages and immature dendritic cells (iDCs) were used as target cells instead of PHA-stimulated PBMCs. It is suggested that inhibition of HIV replication by this Ab for macrophages and iDCs can occur by two distinct mechanisms, neutralization of infectivity involving only the Fab part of the IgG, and, an IgG-FcγR-dependent interaction leading to endocytosis and degradation of HIV particles. Holl2006 (neutralization, dendritic cells)
2G12: Viruses with cleavage-competent 2G12-knockout Env and cleavage-defective Env able to bind 2G12 were constructed. The amount of Env precipitated by 2G12 was same when the two pseudotyped virus variants were mixed as with the wildtype alone, suggesting formation of heterotrimers consisting of both cleavage-competent and defective Envs. The presence of nonfunctional Envs on the surface of infectious virions did not affect the neutralization by 2G12. The neutralization by the CD4-binding agents was also unaffected by 2G12 binding to uncleaved Env indicating that the function of a trimer is unaffected sterically by the binding of an antibody to adjacent trimer. Herrera2006 (neutralization, binding affinity)
2G12: Inhibition of R5 HIV replication by monoclonal and polyclonal IgGs and IgAs in iMDDCs was evaluated. The neutralizing activity of 2G12 was higher in iMDDCs than in PHA-stimulated PBMCs. A 90% reduction of HIV infection was observed without induction of MDDC maturation by this MAb. Blockade of FcgammaRII on iMDDCs decreased the anti-HIV activity of 2G12 while increased expression of FcgammaRI increased inhibition of HIV by 2G12, suggesting the involvement of these receptors in the HIV-inhibitory activity of this Ab. Holl2006a (neutralization, dendritic cells)
2G12: G1 and G2 recombinant gp120 proteins, consisting of 2F5 and 4E10, and 4E10 epitopes, respectively, engrafted into the V1/V2 region of gp120, were tested as an immunogen to see if they could elicit MPER antibody responses. Deletion of V1/V2 from gp120 or its replacement with G1 and G2 grafts, did not greatly affect binding of 2G12 to gp120. Shortening of the N and C termini of the V3 loop nearly abolished binding of 2G12. Law2007 (vaccine antigen design)
2G12: This review describes the effectiveness of the current HIV-1 immunogens in eliciting neutralizing antibody responses to different clades of HIV-1. It also summarizes different evasion and antibody escape mechanisms, as well as the most potent neutralizing MAbs and their properties. MAbs reviewed in this article are: 2G12, IgG1b12, 2F5, 4E10, A32, 447-52D and, briefly, D50. Novel immunogen design strategies are also discussed. Haynes2006a (antibody binding site, neutralization, variant cross-reactivity, escape)
2G12: 2G12 was used as a negative control to investigate the relationship of MAb 412d epitope to the CCR5 binding site of gp120. These two MAbs were incubated with soluble CD4 and ADA gp120 in the presence of a peptide shown to block the association of gp120-CD4 with CCR5. As expected, the presence of the peptide did not inhibit precipitation of gp120 by 2G12, since it binds an epitope distinct from the CCR5 binding domain, while it did inhibit the 412d. Choe2003 (antibody binding site)
2G12: The gp140δCFI protein of CON-S M group consensus protein and gp140CFI and gp140CF proteins of CON6 and WT viruses from HIV-1 subtypes A, B and C were expressed in recombinant vaccinia viruses and tested as immunogens in guinea pigs. 2G12 was shown to bind specifically to all recombinant proteins except for the subtype B gp140δCF and subtype A gp140δCFI. The specific binding of this Ab to CON-S indicated that its conformational epitope was intact. This Ab also bound specifically to the two tested subtype B gp120 proteins. Liao2006 (antibody binding site, vaccine antigen design, subtype comparisons)
2G12: Cross-neutralization was limited in this study. 2G12 neutralized subtype A strain UG273 and subtype B strains US2, NL4-3, and IIIB. It did not neutralize subtype C strain ETH2220, subtype D UG270, CRF01 A/E ID12; subtype F BZ163; nor subtype G BCF06. 3 HIV-2 strains and SIVmac 251 were also not neutralized. 2G12 bound to MN and NDK, but did not neutralize them. Neutralization resistance was selected in culture using strains NL43 and IIIB. NL43 escaped via loss of the glycosylation sequon at positions 295-297, IIIB escaped via sequon losses at positions 392-394 and 295-297, or 406-408, as expected from earlier studies defining critical mannose residues for 2G12 binding. The loss of the mannose actually enhanced mannose-specific lectin inhibition of the virus. Huskens2007 (antibody binding site, neutralization, variant cross-reactivity, escape, subtype comparisons)
2G12: Binding of 2G12 to gp120 was not significantly affected by the small molecule HIV-1 entry inhibitor IC9564. IC9564 induces conformational change of gp120 to allow CD4i antibody 17b to bind, but inhibits CD4-induced gp41 conformational changes. Huang2007 (antibody binding site)
2G12: The neutralizing activity of this antibody for the JR-FL Env variant with the N160K/E160K mutations was measured in comparison with the neutralizing activity of 2909, which was found to be higher. Honnen2007 (neutralization, variant cross-reactivity)
2G12: Controlled attachment of Ab-bound HIV to cells was not affected by the presence of this Ab. However, the virus was still efficiently neutralized indicating that binding of 2G12 to the cell-free virus interferes with a step of infection subsequent to cell attachment. Haim2007 (antibody binding site, neutralization, kinetics)
2G12: This Ab was used to help define the antigenic profile of envelopes used in serum depletion experiments to attempt to define the neutralizing specificities of broadly cross-reactive neutralizing serum. It bound to JR-FL and JR-CSF gp120 monomers and to a lesser extent to core JR-CSF gp120 monomer. Dhillon2007 (antibody binding site, neutralization)
2G12: SOSIP Env proteins are modified by the introduction of a disulfide bond between gp120 and gp41 (SOS), and an I559P (IP) substitution in gp41, and form trimers. The KNH1144 subtype A virus formed more stable trimers than did the prototype subtype B SOSIP Env, JRFL. The stability of gp140 trimers was increased for JR-FL and Ba-L SOSIP proteins by substituting the five amino acid residues in the N-terminal region of gp41 with corresponding residues from KNH1144 virus. b12, 2G12, 2F5, 4E10 and CD4-IgG2 all bound similarly to the WT and to the stabilized JRFL SOSIP timers, suggesting that the trimer-stabilizing substitutions do not impair the overall antigenic structure of gp140 trimers. Dey2007
2G12: 15 subtype A HIV-1 envelopes from early in infection were not neutralized by 2G12, likely because of a deletion or shift in one or more of the 5 glycosylation sites associated with 2G12 recognition. SF162 was neutralized as expected. Blish2007 (neutralization, acute/early infection, subtype comparisons)
2G12: This Ab was found to be able to bind to a highly stable trimeric rgp140 derived from a HIV-1 subtype D isolate containing intermonomer V3-derived disulfide bonds and lacking gp120/gp41 cleavage. Billington2007
2G12: Yeast display was compared to phage display and shown to select all the scFv identified by phage display and additional novel antibodies. Biotinylated C11 and 2G12 were used to minimize selection of non-gp120 specific clones from the yeast displayed antibody library; these MAbs were used as they have unique epitopes with limited overlap with most known epitopes. Bowley2007 (assay or method development)
2G12: Four consensus B Env constructs: full length gp160, uncleaved gp160, truncated gp145, and N-linked glycosylation-site deleted (gp160-201N/S) were compared. All were packaged into virions, and all but the fusion defective uncleaved version mediated infection using the CCR5 co-receptor. Primary isolate Envs were completely resistant or just somewhat sensitive to neutralization by 2G12 while the consensus B constructs were sensitive. Thus the 2G12 epitope is present on the consensus B Env glycoprotein and was not influenced by the Env modifications in this study. Kothe2007 (vaccine antigen design, variant cross-reactivity)
2G12: Newborn macaques were challenged orally with the highly pathogenic SHIV89.6P and then treated intravenously with a combination of IgG1b12, 2G12, 2F5 and 4E10 one and 12 hours post-virus exposure. All control animals became highly viremic and developed AIDS. In the group treated with mAbs 1 hour post-virus exposure, 3/4 animals were protected from persistent systemic infection and one was protected from disease. In the group treated with mAbs 12 hour post-virus exposure, one animal was protected from persistent systemic infection and disease was prevented or delayed in two animals. IgG1b12, 2G12, and 4E10 were also given 24 hours after exposure in a separate study; 4/4 treated animals become viremic, but with delayed and lower peak viremia relative to controls. 3/4 treated animals did not get AIDS during the follow up period, and 1 showed a delayed progression to AIDS , while the 4 untreated animals died of AIDS. Thus the success of passive immunization with NAbs depends on the time window between virus exposure and the start of immunoprophylaxis. Ferrantelli2007 (immunoprophylaxis)
2G12: Antigens were designed to attempt to target immune responses toward the IgG1b12 epitope, while minimizing antibody responses to less desirable epitopes. One construct had a series of substitutions near the CD4 binding site (GDMR), the other had 7 additional glycans (mCHO). The 2 constructs did not elicit b12-like neutralizing antibodies, but both antigens successfully dampened other responses that were intended to be dampened while not obscuring b12 binding. 2G12 had diminished binding to both antigen constructs. Selvarajah2005 (vaccine antigen design, vaccine-induced immune responses)
2G12: Concanavalin A (ConA) binds to mannose and blocks 2G12 binding, but 2G12 does not block ConA binding. ConA binding is less sensitive to mutations in glycosylation sites than 2G12. Furthermore, ConA neutralizes HIV-1 at a post-CD4 binding step. Thus, this report indicates that designing antigens based on the HIV-1 mannose residues that bind ConA may be an effective vaccine strategy, as antibodies elicited might be broadly cross-reactive. Pashov2005 (vaccine antigen design)
2G12: Passive immunization of 8 HIV-1 infected patients with 4E10, 2F5 and 2G12 (day 0, 4E10; days 7, 14 and 21 4E10+2G12+2F5; virus isolated on days 0 and 77) resulted in 0/8 patients with virus that escaped all three NAbs. Three patients had viruses that escaped 2G12, and two of these were sequenced. Each had lost two of the glycosylation sites required for 2G12 binding (one had 295 N->D and 332 N->T changes, the other had 295 N->T and 392 N->T changes). In a companion in vitro study, resistance to a single MAb emerged in 3-22 weeks, but triple combination resistance was slower and characterized by decreased viral fitness. In contrast to the in vivo escape study, only one N was lost in the in vitro experiments, a 386 N->K change in a triple resistant mutant. The lack of resistance to the combination of MAbs in vivo and the reduced fitness of the escape mutants selected in vitro suggests passive immunotherapy may be of value in HIV infection. Nakowitsch2005 (escape, immunotherapy)
2G12: Nine anti-gp41 bivalent Fabs that interacted with either or both of the six-helix bundle and the internal coiled-coil of N-helices of gp41 were selected from a non-immune human phage display library. The IC50 the range for the inhibition of LAV ENV-mediated cell-fusion was 6-61 ug/ml -- for context, 2F5 and 2G12 (IC50s of 0.5-1.5 ug/ml) were about an order of magnitude more potent in this assay than the best Fabs generated here. Louis2005 (neutralization)
2G12: Retrovirus inactivation for vaccine antigen delivery was explored through lipid modification by hydrophobic photoinduced alkylating probe 1.5 iodonaphthylazide (INA). The viral proteins were shown to be structurally intact in the treated non-infectious virus, through the preservation of antibody binding sites for polyclonal anti-gp120 serum, and for broadly neutralizing MAbs 2G12, b12 and 4E10, although the modifications of the lipid disabled viral infection. Raviv2005 (vaccine antigen design)
2G12: This study is about the V2 MAb C108g, that is type-specific and neutralizes BaL and HXB2. JR-FL is a neutralization resistant strain; modification of JRFL at V2 positions 167 and 168 (GK->DE) created a C108g epitope, and C108g could potently neutralize the modified JR-FL. The modification in V2 also increased neutralization sensitivity to V3 MABs 4117c, 2219, 2191, and 447-52D, but only had minor effects on neutralization by CD4BS MAb 5145A, and broadly neutralizing MAbs IgG1b12, 2G12, and 2F5. Pinter2005 (antibody binding site)
2G12: The HIV-1 Bori-15 variant was adapted from the Bori isolate for replication in microglial cells. Bori-15 had increased replication in microglial cells and a robust syncytium-forming phenotype, ability to use low levels of CD4 for infection, and increased sensitivity to neutralization by sCD4 and 17b. Four amino acid changes in gp120 V1-V2 were responsible for this change. Protein functionality and integrity of soluble, monomeric gp120-molecules derived from parental HIV-1 Bori and microglia-adapted HIV-1 Bori-15 was assessed in ELISA binding assays using CD4BS MAbs F105 and IgG1b12, glycan-specific 2G12, and V3-specific 447-52D, and were unchanged. Association rates of sCD4 and 17b were not changed, but dissociation rates were 3-fold slower for sCD4 and 14-fold slower for 17b. Martin-Garcia2005 (antibody binding site)
2G12: Sera from subtype A infected individuals from Cameroon have antibodies that react strongly with subtype A and subtype B V3 loops in fusion proteins, and neutralize SF162 pseudotypes, while sera from 47 subtype B infected individuals reacted only with subtype B V3s. Sera from Cameroon did not neutralize primary A or B isolates, due to indirect masking by the V1/V2 domain rather than due to loss of the target epitope. Neutralization by Cameroonian sera MAbs was blocked by Clade A and B V3 loop fusion proteins, while NAbs to non-V3 epitopes, 2F5, 2G12, and b12, were not blocked. Krachmarov2005 (antibody binding site, variant cross-reactivity, subtype comparisons)
2G12: Of 35 Env-specific MAbs tested, only 2F5, 4E10, IgG1b12, and two CD4BS adjacent MAbs (A32 and 1.4G) and gp41 MAbs (2.2B and KU32) had binding patterns suggesting polyspecific autoreactivity, and similar reactivities may be difficult to induce with vaccines because of elimination of such autoreactivity. Unlike the other three broadly neutralizing human anti-HIV-1 MAbs, 2G12 has no indication of polyspecific autoreactivity. Haynes2005 (antibody binding site)
2G12: 2909 is a human anti-Env NAb that was selected by a neutralization assay and binds to the quaternary structure on the intact virion. ELISA-based competition assays and subsequent mutational analysis determined that the CD4BS and V2 and V3 loops contribute to the 2909 epitope: 2909 binding was inhibited by MAbs 447-52d (anti-V3), 830A (anti-V2), and IgG1b12 (anti-CD4BS) and sCD4. 2909 was not inhibited by MAbs 670, 1418, nor 2G12; in fact, 2G12 enhanced 2909 binding. Gorny2005
2G12: Precise characterization of 2G12 binding to carbohydrate was undertaken; the 2G12 Fab was co-crystallized with four oligomannose derivatives, Man4, Man5, Man7 and Man8. 2G12 recognizes the terminal Manα1-2Man both in the context of the D1 arm (Manα1-2Manα1-2Man) and D3 arm (Manα1-2Manα1-6Man) of the Man9GlcNAc2 moiety, but not the D2 arm. This gives the 2G12 more binding flexibility than previously thought, as only the D1 arm binding had been shown previously. Calarese2005 (antibody binding site, structure)
2G12: The lack of glycosylation sites at residues Asn 295 and Thy 394 within C-clade gp120s generally causes the loss of 2G12 recognition. Introduction of glycans in the subtype C strain HIV-1CN54 at these positions restored 2G12 binding, and addition of just a single glycan partially restored binding (V295N + A394T >> V295N > A395T). 2G12 epitope recovery decreased b12 binding. Chen2005 (antibody binding site)
2G12: By adding N-linked glycosylation sites to gp120, epitope masking of non-neutralizing epitopes can be achieved leaving the IgG1b12 binding site intact. This concept was originally tested with the addition of four glycosylation sites, but binding to b12 was reduced. It was modified here to exclude the C1 N-terminal region, and to include only three additional glycosylation sites. This modified protein retains full b12 binding affinity and it binds to the neutralizing MAb 2G12. It masks other potentially competing epitopes, and does not bind to 21 other MAbs to 7 epitopes on gp120. Pantophlet2004 (vaccine antigen design)
2G12: Infusions of 2F5 and 2G12 intravenously administered 24h prior to vaginal SHIV-89.P challenge are able to protect macaques from infections. Animals that receive a IL-2 adjuvanted DNA immunization SIV Gag and HIV Env have T-cell responses and lower viral loads, but were not protected. Suboptimal levels of 2F5 and 2G12 were not able to confer sterile protection in combination with the T-cell responses stimulated by DNA immunizations. Mascola2003
2G12: Nabs against HIV-1 M group isolates were tested for their ability to neutralize 6 randomly selected HIV-1 O group strains. 2G12 did not neutralize O group strains, although it was included in a quadruple combination of b12, 2F5, 2G12, and 4E10, that neutralized the six Group O viruses between 62-97%. Ferrantelli2004a (variant cross-reactivity)
2G12: Neonatal rhesus macaques were exposed orally to a pathogenic SHIV, 89.6P. 4/8 were given an intramuscular, passive immunization consisting of NAbs 2G12, 2F5 and 4E10, each given at a different body sites at 40 mg/kg per Ab, at one hour and again at 8 days after exposure to 89.6P. The four animals that were untreated all died with a mean survival time of 5.5 weeks, the four animals that got the NAb combination were protected from infection. This model suggests Abs may be protective against mother-to-infant transmission of HIV. Ferrantelli2004 (mother-to-infant transmission)
2G12: 93 viruses from different clades were tested for their neutralization cross-reactivity using a panel of HIV antibodies. 2G12 primarily neutralized B clade viruses with sporadic neutralization of A, D, and two AC recombinants, and no C or CRF01 (E) isolates. Envelopes from subtypes C and E have generally lost critical glycans for 2G12 binding. Binley2004 (variant cross-reactivity, subtype comparisons)
2G12: Env sequences were derived from 4 men at primary infection and four years later; the antigenicity in terms of the ability to bind to 2G12, 2F5 and IgG1b12 was determined. 2G12 bound primarily to late clones in 3 of the 4 patients, and to both early and late in the other patient. Neither 2F5 nor IgG1b12 showed a difference in binding affinity to early or late envelopes. The number of glycosylation sites increased in the three patients. The ability to bind to 2G12 correlated perfectly with having all three sites known to be important for binding: N295 in C2, N332 in C3, and N392 in the V4 loop. Dacheux2004 (antibody binding site, acute/early infection, kinetics)
2G12: Crystal structure analysis of Fab 2G12 alone or complexed with Manα1-2Man or Man9GlcNac2 demonstrates that the exchange of VH domains forms stable dimers for gp120 binding. Two Fabs assemble in an interlocked VH domain swapped dimer, providing an extended surface for multivalent interaction with the cluster of oligomannose on gp120, allowing high-affinity recognition of repeated epitopes in the carbohydrate structure. Ala substitutions of the 2G12 VH/VH' interface residues Ile H19, Arg H57, Phe H77, Tyr H80, Val H84 and Pro H113 result in the loss of 2G12-gp120 JR-FL binding. Calarese2003 (antibody binding site, antibody sequence, structure)
2G12: Synthetic mannose Man9 clusters arranged on a scaffold were used to mimic the epitope of 2G12. Bi-, tri, and tetra-valent clusters had a 7-, 22-, and 73-fold higher affinities for 2G12 than the monomers, suggesting that 2G12 binds best to multiple carbohydrate moieties. 2G12 bound larger mannose oligosaccharides with higher affinity: Ma9GlcNAc bound 210- and 74-fold more effectively that Man6GlcNac and Man5GlcNAc, respectively. Wang2004 (antibody binding site)
2G12: This review discusses research presented at the Ghent Workshop of prevention of breast milk transmission and immunoprophylaxis for HIV-1 in pediatrics (Seattle, Oct. 2002), and makes the case for developing passive or active immunoprophylaxis in neonates to prevent mother-to-infant transmission. Macaque studies have shown that passive transfer of NAb combinations (for example, IgG1b12, 2G12, 2F5, and 4E10; or 2G12 and 2F5) can confer partial or complete protection to infant macaques from subsequent oral SHIV challenge. Safrit2004 (immunoprophylaxis, mother-to-infant transmission)
2G12: A primary isolate, CC1/85, was passaged 19 times in PBMC and gradually acquired increased sensitivity to FAb b12 and sCD4 that was attributed to changes in the V1V2 loop region, in particular the loss of a potential glycosylation site. The affinity for sCD4 was unchanged in the monomer, suggesting that the structural impact of the change was manifested at the level of the trimer. The passaged virus, CCcon19, retained an R5 phenotype and its neutralization susceptibility to other Abs was essentially the same as CC1/85. The IC50 for 2G12 was 1.8 for CC1/85, and was 4.2 for CCcon19, so both the primary and passaged viruses were neutralized. Pugach2004 (variant cross-reactivity, viral fitness and reversion)
2G12: V1V2 was determined to be the region that conferred the neutralization phenotype differences between two R5-tropic primary HIV-1 isolates, JRFL and SF162. JRFL is resistant to neutralization by many sera and MAbs, while SF162 is sensitive. All MAbs tested, anti-V3, -V2, -CD4BS, and -CD4i, (except the broadly neutralizing MAbs IgG1b12, 2F5, and 2G12, which neutralized both strains), neutralized the SF162 pseudotype but not JRFL, and chimeras that exchanged the V1V2 loops transferred the neutralization phenotype. 2G12 was the only MAb that neutralized JRFL more efficiently than SF162, with a 6-fold lower ND50 for JRFL. 2G12 also had a higher affinity for JRFL. Pinter2004 (variant cross-reactivity)
2G12: An antigen panel representing different regions of gp41 was generated, and sera from 23 individuals were screened. 2G12 was a control, binding to gp120 but to none of the gp41 peptides in the experiment. Opalka2004 (assay or method development)
2G12: A set of HIV-1 chimeras that altered V3 net charge and glycosylation patterns in V1V2 and V3, involving inserting V1V2 loops from a late stage primary isolate taken after the R5 to X4 switch, were studied with regard to phenotype, co-receptor usage, and MAb neutralization. The loops were cloned into a HXB2 envelope with a LAI viral backbone. It was observed that the addition of the late-stage isolate V1V2 region and the loss of V3-linked glycosylation site in the context of high positive charge gave an X4 phenotype. R5X4 viruses were more sCD4 and 2G12 neutralization resistant than either R5 or X4, but the opposite pattern was observed for b12. Addition of the late stage V1V2 altered neutralization for both MAbs, but this alteration was reversed with the loss of the V3 glycan. Nabatov2004 (antibody binding site, co-receptor)
2G12: Mice susceptible to MV infection were intraperitoneally immunized with native HIV-1 89.6 env gp160 and gp140 and δV3 HIV-1 89.6 mutants expressed in live attenuated Schwarz measles vector (MV). The gp160ΔV3 construct raised more cross-reactive NAbs to primary isolates. A HIVIG/2F5/2G12 combination was used as a positive control and could neutralize all isolates. Lorin2004 (vaccine antigen design)
2G12: 2G12 was used as a positive control in a study that showed that A32-rgp120 complexes open up the CCR5 co-receptor binding site, but did not induce neutralizing antibodies with greater breadth among B subtype isolates than did uncomplexed rgp120 in vaccinated guinea pigs. Liao2004 (vaccine antigen design)
2G12: A set of oligomeric envelope proteins were made from six primary isolates for potential use as vaccine antigens: 92/UG/037 (clade A), HAN2/2 (clade B), 92/BR25/025 (clade C), 92/UG/021 (clade D), 93/BR/029 (clade F) and MVP5180 (clade O). This was one of a panel of MAbs used to explore folding and exposure of well characterized epitopes. The clade C isolate BR25 is apparently misfolded, as conformation-dependent antibodies did not bind to it. 2G12 bound to clade A, B, D and F HIV-1 primary isolates. Polyclonal sera raised in rabbits against these antigens cross-bound the other antigens, but none of the sera had neutralizing activity. Jeffs2004 (vaccine antigen design, subtype comparisons)
2G12: The peptide 12p1 (RINNIPWSEAMM) inhibits direct binding of YU2 gp120 or Env trimer to CD4, CCR5 and MAb 17b in a concentration-dependent allosteric manner. 12p1 is thought to bind to unbound gp120 near the CD4 binding site, with a 1:1 stoichiometry. 12p1 also inhibited MAb F105 binding; presumably because F105 favors an unactivated conformation, but not MAbs 2G12 or b12. The 1:1 stoichiometry, the fact that the peptide binding site is accessible on the trimer, the non-CD4 like aspect of the binding, and an ability to inhibit viral infection in cell cultures make it a promising lead for therapeutic design. Biorn2004
2G12: This paper is a review of anti-HIV-1 Envelope antibodies. This unique epitope is formed from carbohydrates. The mechanism of MAb neutralization is thought to be steric inhibition of CCR5 binding. 2G12 neutralizes many TCLA strains and about 40% of primary isolates tested. Gorny2003 (review)
2G12: A gp120 molecule was designed to focus the immune response onto the IgG1b12 epitope. Ala substitutions that enhance the binding of IgG1b12 and reduce the binding of non-neutralizing MAbs were combined with additional N-linked glycosylation site sequons inhibiting binding of non-neutralizing MAbs; b12 bound to the mutated gp120. C1 and C5 were also removed, but this compromised b12 binding. Pantophlet2003b (vaccine antigen design)
2G12: scFv 4KG5 reacts with a conformational epitope. Of a panel of MAbs tested, only NAb b12 enhanced 4KG5 binding to gp120. MAbs to the V2 loop, V3 loop, V3-C4 region, and CD4BS diminished binding, while MAbs directed against C1, CD4i, C5 regions didn't impact 4KG5 binding. These results suggest that the orientation or dynamics of the V1/V2 and V3 loops restricts CD4BS access on the envelope spike, and IgG1b12 can uniquely remain unaffected. 2G12 had no impact on 4KG5 binding. Zwick2003a (antibody interactions)
2G12: The broadly neutralizing antibodies 2F5 and 2G12 were class-switched from IgG to IgA and IgM isotypes. Neutralizing potency was increased with valence for 2G12 so the IgM form was most potent, but for 2F5 the IgG form was most potent. Eight primary isolates were tested including two subtype A isolates. The polymeric IgM and IgA Abs, but not the corresponding IgGs, could interfere with HIV-1 entry across a mucosal epithelial layer, although they were limited in a standard neutralization assay. All isotypes could interact with activated human sera, presumably through complement, to inhibit HIV replication. Wolbank2003 (complement, genital and mucosal immunity, isotype switch, variant cross-reactivity, subtype comparisons)
2G12: The antiviral response to intravenously administered MAbs 2F5 and 2G12 was evaluated in 7 HAART-naïve asymptomatic HIV-1 infected patients during a treatment period of 28 days. MAb therapy reduced plasma HIV RNA in 3/7 patients during the treatment period, and transiently reduced viral load in two more. CD4 counts were up in 3/7 through day 28, and transiently increased in three more. Vigorous complement activation was observed after 48/56 Ab infusions. Virus derived from 2/7 patients could be neutralized by 2G12, and escape from 2G12 was observed in both cases after infusion; one year after the infusion, isolates were again sensitive to 2G12. Stiegler2002 (complement, variant cross-reactivity, escape, immunotherapy)
2G12: Env genes derived from uncultured brain biopsy samples from four HIV-1 infected patients with late-stage AIDS were compared to env genes from PBMC samples. Brain isolates did not differ in the total number or positions of N-glycosylation sites, patterns of coreceptor usage, or ability to be recognized by gp160 and gp41 MAbs. 2G12 was the only MAb tested to recognize all blood and brain isolates from all four patients by gp120 immunoprecipitation. Ohagen2003 (variant cross-reactivity)
2G12: AC10 is a subject who was given treatment early after infection, and had a viral rebound after cessation of therapy, which then declined to a low level. The polyclonal sera from AC10 could potently neutralize the rebound virus, and NAb escape followed with a neutralizing response against the escape variant and subsequent escape from that response. Viral loads remained low in this subject despite escape. The rebound isolate that was potently neutralized by autologous sera was not particularly neutralization sensitive, as it resisted neutralization by sCD4 and MAbs IgG1b12, 2G12 and 2F5, and was only moderately sensitive to sera from other HIV+ individuals that had high titers of NAbs to TCLA strains. Montefiori2003 (acute/early infection, escape)
2G12: Polyclonal Abs raised against soluble trivalently linked N35CCG-N13 and N34CCG, the internal trimeric core of the coiled-coil ectodomain, inhibit HIV-1 Env-mediated cell fusion at levels comparable to 2G12. Louis2003 (vaccine antigen design)
2G12: Thermodynamics of binding to gp120 was measured using isothermal titration calorimetry for sCD4, 17b, b12, 48d, F105, 2G12 and C11 to intact YU2 and the HXBc2 core. The free energy of binding was similar, except for 2G12, which might not have bound well to the carbohydrate additions on the Drosophila expressed core. Enthalpy and entropy changes were divergent, but compensated. Not only CD4 but MAb ligands induced thermodynamic changes in gp120 that were independent of whether the core or the full gp120 protein was used. Non-neutralizing CD4BS and CD4i MAbs (17b, 48d, 1.5e, b6, F105 and F91) had large entropy contributions to free energy (mean: 26.1 kcal/mol) of binding to the gp120 monomer, but the potent CD4BS neutralizing MAb b6 had a much smaller value of 5.7 kcal/mol. The high values suggest surface burial or protein folding an ordering of amino acids. 2G12 had an entropy value of -1.6. These results suggest that while the trimeric Env complex has four surfaces, a non-neutralizing face (occluded on the oligomer), a variable face, a neutralizing face and a silent face (protected by carbohydrate masking), gp120 monomers further protect receptor binding sites by conformational or entropic masking, requiring a large energy handicap for Ab binding not faced by other anti-gp120 Abs. Kwong2002 (antibody binding site)
2G12: MAbs IgG1b12, 2G12, 2F5 and 4E10 were tested for their ability to neutralize two primary HIV-1 clade A isolates (UG/92/031 and UG/92/037) and two primary HIV-1 clade D isolates (UG/92/001 and UG/92/005). 4E10 demonstrated the most potent cross-neutralization activity. Quadruple administration of MAbs IgG1b12, 2G12, 2F5, and 4E10 induced strong synergistic neutralization of 4 clade A isolates (UG/92/031, UG/92/037, RW/92/020 and RW/92/025) as well as 5 clade D isolates (UG/92/001,UG/9/005, /93/086/RUG/94/108, UG/94/114). The authors note this combination of 4 MAbs neutralizes primary HIV A, B, C, and D isolates. Kitabwalla2003 (antibody interactions, immunoprophylaxis, variant cross-reactivity, mother-to-infant transmission, subtype comparisons)
2G12: This paper shows that binding of CD4BS MAbs to Env blocks the conformational shift that allows co-receptor CCR5 binding and CD4-independent mediated cell fusion. CD4BS MAbs IgG1b12, F91 and F105 and their Fab counterparts (except for C11, used as a negative control) inhibited CD4-independent JR-FL and YU-2 gp120-CCR5 binding to CCR5-expressing Cf2Th cells and syncytium formation. The carbohydrated binding MAb 2G12 also inhibited CD4-independent syncytium formation. Raja2003 (co-receptor)
2G12: To begin to design vaccine antigens that can mimic the carbohydrate structure, the gp120 peptide 336-342 was synthesized with Man(9), Man(6), and Man(5) moieties attached. Singh2003 (vaccine antigen design)
2G12: Review of current neutralizing antibody-based HIV vaccine candidates and strategies of vaccine design. Strategies for targeting of the epitopes for NAbs 2F5, 2G12, 4E10, b12, and Z13 are described. They have shown that both N-glycans, at 295N and 332N are required for 2G12 binding, emphasizing the oligosaccharide cluster nature of the epitope, and suggest the uniqueness of the target structure may not result in autoimmune reactions. Wang2003 (vaccine antigen design, review)
2G12: Most plasma samples of patients from early infection had NAb responses to early autologous viruses, and NAbs against heterologous strains tended to be delayed. Serial plasma samples were tested against serial isolates, and neutralization escape was shown to be rapid and continuous throughout infection. Autologous neutralization-susceptible and resistant viruses from four patients were tested for susceptibility to neutralizing Ab responses using MAbs 2G12, IgG1b12 and 2F5. No correlation was established, all viruses tested were susceptible to at least one of the neutralizing MAbs. Two patients that did not have an autologous NAb response also did not evolve changes in susceptibility to these MAbs, while one patient with a pattern of autologous neutralization and escape acquired a 2G12 sensitive virus at month 6, and lost IgG1b12 sensitivity at month 21. Richman2003 (autologous responses, acute/early infection, escape)
2G12: This review discusses the importance and function of protective antibody responses in animal model studies in the context of effective vaccine development. SHIV models have shown protection using high levels of MAbs can prevent infection, and partial protection that can influence disease course can be obtained from modest levels of NAbs. SHIV challenges studies conducted with infusions of combinations of MAbs b12, 2G12, and 2F5 are reviewed. Mascola2003a (immunoprophylaxis, review)
2G12: This study investigates the effects of glycosylation inhibitors on the binding between HIV-1 gp120 and mannose-binding lectin (MBL). Mannosidase I inhibitor deoxymannojirimycin (dMM) inhibits formation of complex and hybrid N-linked saccharides and yields virus with more mannose residues. dMM added during viral production significantly enhanced the binding 2F5 and 2G12, but not IgG1b12 in a viral capture assay. Hart2003 (antibody binding site)
2G12: UK1-br and MACS2-br are R5 isolates derived from brain tissue samples from AIDS patients with dementia and HIV-1 encephalitis; both are neurotropic, but only UK1-br induced neuronal apoptosis and high levels of syncytium formation in macrophages. UK1-br Env had a greater affinity for CCR5 than MACS-br, and required low levels of CCR5 and CD4 for cell-to-cell fusion and single round infection. PBMC infected with UK1-br and MACS2-br virus isolates were resistant to neutralization by MAb 2G12. UK1-br was more sensitive than MACS2-br to IgG1b12, 2F5 and CD4-IgG2 neutralization. Gorry2002 (brain/CSF, co-receptor)
2G12: Four newborn macaques were challenged with pathogenic SHIV 89.6 and given post exposure prophylaxis using a combination of NAbs 2F5, 2G12, 4E10 and IgG1b12. 2/4 treated animals did not show signs of infection, and 2/4 macaques maintained normal CD4+ T cell counts and had a lower delayed peak viremia compared to the controls. Ferrantelli2003 (immunoprophylaxis, mother-to-infant transmission)
2G12: A sCD4-17b single chain chimera was made that can bind to the CD4 binding site, then bind and block co-receptor interaction. This chimeric protein is a very potent neutralizing agent, more potent than IgG1b12, 2G12 or 2F5 against Ba-L infection of CCR5-MAGI cells. It has potential for prophylaxis or therapy. Dey2003 (co-receptor)
2G12:The MAb B4e8 binds to the base of the V3 loop, neutralizes multiple primary isolates and was studied for interaction with other MAbs. B4e8 and 2G12 enhanced each other's binding, and gave synergistic neutralization. B4e8 could neutralize R5X4 virus 92HT593 better than 2G12, while 2G12 was better at neutralizing R5 virus 92US660. Cavacini2003 (antibody interactions)
2G12: This study examined Ab interactions, binding and neutralization with a B clade R5 isolate (92US660) and R5X4 isolate (92HT593). Abs generally bound and neutralized the R5X4 isolate better than the R5 isolate. Anti-gp41 MAb F240 did not affect binding of 2G12 to either R5X4 and R5 isolates, and anti-V3 MAb B4a1 increased 2G12 binding to R5X4 virions but not R5. Neutralization with B4al and 2G12 was additive for the R5X4 virus, and was enhanced for the R5 virus. Cavacini2002 (antibody interactions, co-receptor, variant cross-reactivity)
2G12: Neutralization assays with rsCD4, MAbs, and serum samples from SHIV-infected macaques and HIV-1 infected individuals were used to characterize the antigenic properties of the env glycoprotein of six primary isolate-like or TCLA SHIV variants. 2G12 neutralized the five SHIV strains tested, HXBc2, KU2, 89.6, 89.6P and KB9, in MT-2 cells. Crawford1999 (variant cross-reactivity)
2G12: The SOS mutant envelope protein introduces a covalent disulfide bond between gp120 surface and gp41 transmembrane proteins into the R5 isolate JR-FL by adding cysteines at residues 501 and 605. Pseudovirions bearing this protein bind to CD4 and co-receptor bearing cells, but do not fuse until treatment with a reducing agent, and are arrested prior to fusion after CD4 and co-receptor engagement. 2G12 is able to neutralize both the wildtype and SOS protein comparably, but 2G12 could not neutralize SOS when added post-attachment. Binley2003 (vaccine antigen design)
2G12: IgG1b12 neutralized many South African (5/8) and Malawian (4/8) clade C primary HIV-1 isolates, being more effective than 2F5 which neutralized only two Malawian and no South African isolates. 2G12 did not neutralize any of the 16 isolates. Bures2002 (subtype comparisons)
2G12: SOS-Env is a mutant protein engineered to have a disulfide bond between gp120 and gp41. Cells expressing SOS-Env due not fuse with target cells expressing CD4 and CCR5, although the fusion process proceeds to an intermediate state associated with CD4 and co-receptors, prior to the formation of the six helix bundle that allows fusion.2G12 was used to monitor surface expression of SOS-Env compared to wildtype. Abrahamyan2003b (co-receptor, vaccine antigen design)
2G12: 2G12 was used as a positive control to test for a NAb activity in mice intranasally immunized with gp120 or gp140 with IL-12 and Cholera Toxin B. Albu2003
2G12: NIH AIDS Research and Reference Reagent Program: 1476.
2G12: UK Medical Research council AIDS reagent: ARP3030.
2G12: CD4BS MAbs b12 (neutralizing) and 205-42-15, 204-43-1, 205-46-9 (non-neutralizing) all cross-competed for binding to monomeric gp120, indicating the topological proximity of their epitopes, however, the non-neutralizing CD4BS MAbs did not interfere with the neutralization activity of MAb b12 -- 2G12 was used to normalize and as a control in these experiments. Herrera2003 (antibody interactions)
2G12: Alanine scanning mutagenesis was used to compare substitutions that affected anti-CD4BS NAb b12 -- rec gp120s were engineered to contain combinations of Alanine substitutions that enhanced b12 binding, and while binding of b12 to these gp120 monomers was generally maintained or increased, binding by five non-neutralizing anti-CD4bs MAbs (b3, b6, F105, 15e, and F91) was reduced or completely abolished -- 2G12 binding was largely unperturbed, indicating these proteins were not grossly misfolded. Pantophlet2003 (antibody binding site)
2G12: Review of NAbs that discusses mechanisms of neutralization, passive transfer of NAbs and protection in animal studies, and vaccine strategies. Liu2002 (review)
2G12: Review of NAbs that notes 2G12 alone or in combination with other MAbs can protect some macaques against SHIV infection, that it has strong ADCC activity, and that it is safe and well tolerated in humans. Ferrantelli2002 (immunoprophylaxis)
2G12: A rare mutation in the neutralization sensitive R2-strain in the proximal limb of the V3 region caused Env to become sensitive to neutralization by MAbs directed against the CD4 binding site (CD4BS), CD4-induced (CD4i) epitopes, soluble CD4 (sCD4), and HNS2, a broadly neutralizing sera -- 2/12 anti-V3 MAbs tested (19b and 694/98-D) neutralized R2, as did 2/3 anti-CD4BS MAbs (15e and IgG1b12), 2/2 CD4i MAbs (17b and 4.8D), and 2G12 and 2F5 -- thus multiple epitopes on R2 are functional targets for neutralization and the neutralization sensitivity profile of R2 is intermediate between the highly sensitive MN-TCLA strain and the typically resistant MN-primary strain. Zhang2002 (antibody binding site)
2G12: Rhesus macaques were better protected from vaginal challenge with SHIV89.6D (MAb 2G12, 2/4; MAbs 2F5/2G12, 2/5; and HIVIG/2F5/2G12, 4/5 infected) than from intravenous challenge (MAb 2G12, 0/3; MAbs 2F5/2G12, 1/3; and HIVIG/2F5/2G12, 3/6 infected)-- the animals that were infected by vaginal challenge after Ab infusion had low or undetectable viral RNA levels and modest CD4 T-cell decline. Mascola2002 (genital and mucosal immunity, immunoprophylaxis)
2G12: HIV-1 gp160deltaCT (cytoplasmic tail-deleted) proteoliposomes (PLs) containing native, trimeric envelope glycoproteins from R5 strains YU2 and JRFL, and X4 strain HXBc2, were made in a physiologic membrane setting as candidate immunogens for HIV vaccines -- 2F5 bound to gp160deltaCT with a reconstituted membrane ten-fold better than the same protein on beads, while such an affinity difference was not seen with F105 and 2G12 -- anti-CD4BS MAbs IgG1b12 and F105, A32 (C1-C4), C11 (C1-C5), and 39F (V3) MAbs bound gp160deltaCT PLs indistinguishably from gp160deltaCT expressed on the cell surface. Grundner2002 (antibody binding site, vaccine antigen design)
2G12: Truncation of the gp41 cytoplasmic domain of X4, R5, and X4R5 viruses forces a conformation that more closely resembles the CD4 bound state of the external Envelope, enhancing binding of CD4i MAbs 17b and 48d and of CD4BS MAbs F105, b12, and in most cases of glycosylation site dependent MAb 2G12 and the anti-gp41 MAb 246D -- in contrast, binding of the anti-V2 MAb 697D and the anti-V3 MAb 694/98D were not affected -- viruses bearing the truncation were more sensitive to neutralization by MAbs 48d, b12, and 2G12 -- the anti-C5 MAb 1331A was used to track levels of cell surface expression of the mutated proteins. EdwardsBH2002 (antibody binding site)
2G12: A modified gp140 (gp140deltaCFI), with C-term mutations intended to mimic a fusion intermediate and stabilize trimer formation, retained antigenic conformational determinants as defined by binding to CD4 and to MAbs 2F5, 2G12, F105, and b12, and enhanced humoral immunity without diminishing the CTL response in mice injected with a DNA vaccine. Chakrabarti2002 (vaccine antigen design)
2G12: Passive immunization of neonate macaques with a combination of F105+2G12+2F5 conferred complete protection against oral challenge with SHIV-vpu+ or -- the combination b12+2G12+2F5 conferred partial protection against SHIV89.6 -- such combinations may be useful for prophylaxis at birth and against milk born transmission -- the synergistic combination of IgG1b12, 2G12, 2F5, and 4E10 neutralized a collection of HIV clade C primary isolates. Xu2002 (antibody interactions, immunoprophylaxis, mother-to-infant transmission)
2G12: Uncleaved soluble gp140 (YU2 strain, R5 primary isolate) can be stabilized in an oligomer by fusion with a C-term trimeric GCN4 motif or using a T4 trimeric motif derived from T4 bacteriophage fibritin -- stabilized oligomer gp140 delta683(-FT) showed strong preferential recognition by NAbs IgG1b12 and 2G12 relative to the gp120 monomer, in contrast to poorly neutralizing MAbs F105, F91, 17b, 48d, and 39F which showed reduced levels of binding, and MAbs C11, A32, and 30D which did not bind the stabilized oligomer. Yang2002 (antibody binding site)
2G12: Ab binding characteristics of SOS gp140 were tested using SPR and RIPA -- SOS gp140 is gp120-gp41 bound by a disulfide bond -- NAbs 2G12, 2F5, IgG1b12, CD4 inducible 17b, and 19b bound to SOS gp140 better than uncleaved gp140 (gp140unc) and gp120 -- non-neutralizing MAbs 2.2B (binds to gp41 in gp140unc) and 23A (binds gp120) did not bind SOS gp140 -- 2G12 complexes with SOS gp140 or with gp120 had a very unusual linear structure. Schulke2002 (antibody binding site, vaccine antigen design)
2G12: Alanine scanning mutagenesis used in conjunction with competition and replacement studies of N-linked carbohydrates and sugars suggest that the 2G12 epitope is formed from mannose residues contributed by the glycans attached to N295 and N332, with the other N-linked carbohydrates in positions N339, N386, and N392 playing a role in maintaining conformation relevant to 2G12 binding -- N295A and N332A mutants showed essentially unchanged anti-CD4BS NAb b12 binding affinities, while N339A, N386A and N392A mutants displayed significantly lowered b12 affinity, presumably due to conformational changes. Scanlan2002 (antibody binding site)
2G12: The 2G12 epitope is composed of carbohydrates involving high-mannose and hybrid glycans of residues 295, 332, and 392, with peripheral glycans from 386 and 448 contributing on either flank, and with little direct gp120 protein surface involvement -- these mannose residues are proximal to each other near the chemokine receptor binding surface. Sanders2002 (antibody binding site)
2G12: The fusion process was slowed by using a suboptimal temperature (31.5 C) to re-evaluate the potential of Abs targeting fusion intermediates to block HIV entry -- preincubation of E/T cells at 31.5 C enabled polyclonal anti-N-HR Ab and anti-six-helix bundle Abs to inhibit fusion, indicating six-helix bundles form prior to fusion -- the preincubation 31.5 C step did not alter the inhibitory activity of neutralizing Abs anti-gp41 2F5, or anti-gp120 2G12, IG1b12, 48d, and 17b. GoldingH2002 (antibody binding site)
2G12: A phase I trial in seven HIV+ individuals was conducted with MAbs 2F5 and 2G12 -- no clinical or laboratory abnormalities were observed throughout the study -- eight infusions were administered over a 4-week period (total dose 14 g) -- the elimination half-life (t_1/2) was calculated to be 7.94 (range, 3.46--8.31) days for 2F5 and 16.48 (range, 12.84--24.85) days for 2G12. Armbruster2002 (kinetics, immunotherapy)
2G12: Chloroquine reduces the HIV-1-infectivity of H9 IIIB cells, apparently through altering the conformation of envelope -- there is a reduction of reactivity of 2G12 to its epitope in chloroquine treated cultures. Savarino2001 (antibody binding site)
2G12: Twenty HIV clade C isolates from five different countries were susceptible to neutralization by anti-clade B MAbs in a synergistic quadruple combination of mAbs IgG1b12, 2G12, 2F5, and 4E10. Xu2001 (antibody interactions, variant cross-reactivity, subtype comparisons)
2G12: A combination of MAbs IgG1b12, 2F5, and 2G12 was given postnatally to four neonates macaques that were then challenged with highly pathogenic SHIV89.6P -- one of the four infants remained uninfected after oral challenge, two infants had no or a delayed CD4(+) T-cell decline. HofmannLehmann2001 (immunoprophylaxis, mother-to-infant transmission)
2G12: A panel of 12 MAbs was used to identify those that could neutralize the dual-tropic primary isolate HIV-1 89.6 -- six gave significant neutralization at 2 to 10 ug/ml: 2F5, 50-69, IgG1b12, 447-52D, 2G12, and 670-D six did not have neutralizing activity: 654-D, 4.8D, 450-D, 246-D, 98-6, and 1281 -- no synergy, only additive effects were seen for pairwise combinations of MAbs, and antagonism was noted between gp41 MAbs 50-69 and 98-6, as well as 98-6 and 2F5. Verrier2001 (antibody interactions)
2G12: A luciferase-reporter gene-expressing T-cell line was developed to facilitate neutralization and drug-sensitivity assays -- luciferase and p24 antigen neutralization titer end points were found comparable using NAb from sera from HIV+ donors, and MAbs 2F5, 2G12 and IgG1b12. Spenlehauer2001 (assay or method development)
2G12: Neutralizing synergy between MAbs 1b12, 2G12 and 2F5 was studied using surface plasmon resonance to determine the binding kinetics for these three MAbs with respect to monomeric and oligomeric Env protein gp160 IIIB -- the 2G12 epitope is highly accessible on both monomeric and oligomeric Envs, 1b12 is highly accessible on monomers but not oligomers, and 2F5 on neither form -- binding of 2G12 exposes the 2F5 epitope on gp160 oligomers -- 2G12-gp160 oligomer interactions were best fitted to a two state model, with the first complex having a high association constant and fast dissociation, stabilized by conformational changes induced by the binding of a second MAb. ZederLutz2001 (antibody binding site, antibody interactions, kinetics)
2G12: Structural aspects of the interaction of neutralizing Abs with HIV-1 Env are reviewed -- Env essentially has three faces, one is largely inaccessible on the native trimer, and two that exposed but have low immunogenicity on primary viruses -- neutralization is suggested to occur by inhibition of the interaction between gp120 and the target cell membrane receptors as a result of steric hindrance and it is noted that the attachment of approximately 70 IgG molecules per virion is required for neutralization, which is equivalent to about one IgG molecule per spike -- the 2G12, 17b and b12 epitopes are discussed in detail -- although it is potently neutralizing, 2G12 does not interfere with CD4 and coreceptor binding, and this Ab specificity is uncommon in sera from HIV-1-infected individuals. Poignard2001 (antibody binding site, review)
2G12: Moore and colleagues review structural aspects of gp120 and how they relate to antigenic domains, and review the data concerning the lack of a clear relationship between genetic subtype and serotype -- an exception exists for human MAb 2G12, which does not recognize CRF01 envelopes because of an unusual additional disulfide bond in the V4 loop region that appears to be unique to the subtype E, CRF01 gp120 protein. Moore2001 (antibody binding site, review)
2G12: SF162DeltaV2 is a virus that has a 30 amino acids deletion in the V2 loop that does not abrogate its infectivity but renders it highly susceptible to neutralization -- when incorporated into a codon-optimized DNA vaccine with a CMV promoter and delivered by gene gun, SF162DeltaV2 gave higher neutralizing Ab titers against SF162 than did SF162 itself, and Abs that cross-neutralized non-homologous primary isolates were obtained only when SF162DeltaV2, but not intact SF162, was used as the immunogen -- Control MAbs 2F5 and 2G12 could neutralize all of the following primary isolates: 91US056(R5), 92US714(R5), 92US660(R5), 92HT593(R5X4), and BZ167(R5X4), while after the first protein boost, the sera from two SF162DeltaV2 immunized macaques could neutralize 91US056(R5), 92US714(R5), 92US660(R5) and ADA(R5), but not 92HT593(R5X4) or 92US657(R5) -- the pattern of cross-recognition shifted after the second boost. Barnett2001a (vaccine antigen design)
2G12: Review of studies in macaques that have shown immune control of pathogenic SHIV viremia, improved clinical outcome, and protection, and the implications of the observations for HIV vaccines. Mascola2001 (review)
2G12: Neutralization synergy between anti-HIV NAbs b12, 2G12, 2F5, and 4E10 was studied -- a classic fixed-ratio method was used, as well as a method where one Ab was fixed at a low neutralization titer and the other was varied -- using primary isolates, a two-four fold enhancement of neutralization was observed with MAb pairs, and a ten-fold enhancement with a quadruple Ab combination -- no synergy was observed with any MAb pair in the neutralization of TCLA strain HXB2 -- there was no evidence for cooperativity of binding between b12 and 2G12 to envelope spikes expressed on the cell surface of TCLA or primary isolates. Zwick2001c (antibody interactions)
2G12: SHIV-HXBc2 is a neutralization sensitive non-pathogenic virus, and several in vivo passages through monkey's yielded highly pathogenic SHIV KU-1 -- HXBc2 and the KU-1 clone HXBc2P3.2 differ in 12 amino acids in gp160 -- substitutions in both gp120 and gp41 reduced the ability of sCD4, IgG1b12, F105 and AG1121 to Env achieve saturation and full occupancy, and neutralize KU-1 -- 17b and 2F5 also bound less efficiently to HXBc2P3.2, although 2G12 was able to bind both comparably. Si2001
2G12: Six mutations in MN change the virus from a high-infectivity neutralization resistant phenotype to low-infectivity neutralization sensitive -- V3, CD4BS, and CD4i MAbs are 20-100 fold more efficient at neutralizing the sensitive form -- 2G12 was an exception and could not neutralize MN in either form. Park2000
2G12: To determine the antigenicity of virus killed by thermal and chemical inactivation, retention of conformation-dependent neutralization epitopes was examined, and exposure of CD4BS epitopes was found to be enhanced (MAbs IgG1b12, 205-46-9, and 205-43-1) -- binding to 2G12 and 447-52D epitopes was essentially unaltered -- the 17b CD4i epitope was also exposed. Grovit-Ferbas2000 (vaccine antigen design)
2G12: A triple combination of 2F5, F105 and 2G12 effectively neutralized perinatal infection of macaque infants when challenged with SHIV-vpu+ -- the mean plasma half-life was 14.0 +/- 7.9 days, the longest of the three Abs. Baba2000 (immunoprophylaxis, mother-to-infant transmission)
2G12: A mini-review of observations of passive administration of IgG NAbs conferring protection against intervenous or vaginal SHIV challenge, that considers why IgG MAbs might protect against mucosal challenge. Database note: First author "RobertGuroff" is also found as "Robert-Guroff" on annotated papers in this database. RobertGuroff2000 (genital and mucosal immunity, immunoprophylaxis, review)
2G12: The MAbs with the broadest neutralizing activity, IgG1b12, 2G12 and 2F5, all have high affinity for the native trimer, indicating that they were raised in an immune response to the oligomer on the virion surface rather than dissociated subunits -- a disulfide linked gp120-gp41 (SOS gp140) was created to mimic the native conformation of Env and explore its potential as an immunogen -- SOS gp140 is recognized by NAbs IgG1b12, 2G12, and CD4-IgG2, and also by anti-V3 MAbs 19b and 83.1 -- SOSgp140 is not recognized by C4 region MAbs that neutralize only TCLA strains, G3-42 and G3-519 -- nor did it bind C11, 23A, and M90, MAbs that bind to gp120 C1 and C5, where it interacts with gp41 -- MAbs that bind CD4 inducible epitopes, 17b and A32 were very strongly induced by CD4 in SOS gp140 -- anti-gp41 MAbs that bind in the region that interacts with gp120, 7B2, 2.2B, T4, T15G1 and 4D4, did not bind to SOSgp140, in contrast to 2F5, which binds to the only gp41 epitope that is well exposed in native gp120-gp41 complexes. Binley2000 (antibody binding site, vaccine antigen design)
2G12: Because HIV-1 is most often transmitted across mucosal surfaces, the ability of passive transfer of infused HIVIG/2F5/2G12 to protect against mucosal exposure of macaques to pathogenic SHIV 89.6PD was studied -- HIVIG/2F5/2G12 protected 4/5 animals against vaginal challenge, 2F5/2G12 combined protected 2/5 animals, and 2G12 alone protected 2/4 animals -- in contrast, Mascola and co-workers had previously shown single MAbs could not protect against intervenous challenge -- Ab treated animals that got infected through vaginal inoculation had low viral loads and only modest declines in CD4 counts -- the infused Abs were detected in the nasal, vaginal, and oral mucosa. Mascola2000a (genital and mucosal immunity, immunoprophylaxis)
2G12: Combinations of HIVIG, 2F5, 2G12 were administered in passive-transfer experiments 24 hours prior to challenge with pathogenic SHIV 89.6PD -- 3/6 animals given HIVIG/2F5/2G12 were completely protected, the others had reduced viremia and normal CD4 counts -- 1/3 monkeys given 2F5/2G12 showed transient infection, the other two had reduced viral load -- all monkeys that received HIVIG, 2F5, or 2G12 alone became infected and developed high-level plasma viremia, although animals that got HIVIG or 2G12 had a less profound CD4 T cell decline. Mascola1999 (antibody interactions)
2G12: Review of the neutralizing Ab response to HIV-1. Parren1999 (review)
2G12: Hu-PBL-SCID mice were infected with HIV-1s JRCSF and SF162 to study the effect of NAbs on an established infection -- no significant differences in the initial rate of decrease in viral load or the plateau levels of viral RNA between the b12 treated and control mice were seen -- in most of the Ab treated mice b12 escape mutants were observed with varying patterns of mutations -- a combination of b12, 2G12 and 2F5 protected 1/3 mice, and an isolate from one of the other two was resistant to neutralization by all three MAbs. Poignard1999 (antibody interactions, escape)
2G12: A Semliki Forest virus (SFV) expression system carrying BX08 Env was used to study the conformation of gp120 Env -- intracytoplasmic gp120 was recognized by the anti-V3 MAbs K24 and F5.5, while gp120 at the plasma membrane was detected only by conformation dependent MAbs 2G12, 670-D and 694/98D and not V3 MAbs -- expression in rat brain also showed that surface expressed Env was recognized only by the conformation-dependent Abs and not by anti-V3 Abs. Altmeyer1999
2G12: rgp120 derived from a R5X4 subtype B virus was used to vaccinate healthy volunteers and the resulting sera were compared with sera from HIV-1 positive subjects and neutralizing MAbs -- 2G12 was able to bind with low affinity to the rgp120 monomer HIV-1 W61D. Beddows1999
2G12: A meeting summary presented results regarding neutralization --MAbs 2G12 and 2F5 tested for their ability to neutralize primary isolate infection of genetically engineered cell lines (cMAGI and others, presented by T. Matthews, A. Trkola, J. Bradac) -- an advantage of such cells lines over PBMCs is that markers (X-Gal) can be added for staining to simplify the assay -- the consensus of the meeting was that these engineered cell lines did not improve the sensitivity of detection of primary isolate neutralization -- D. Burton and J. Mascola presented results concerning passive immunization and protection of hu-PBL-SCID mice and macaques, respectively, and both found combinations of MAbs that were able to achieve 99% neutralization in vitro corresponded to efficacy in vivo. Montefiori1999 (review)
2G12: Infection of dendritic cells cultured from CD14+ blood cells or from cadaveric human skin was blocked by neutralizing MAbs IgG1b12, or 2F5 and 2G12 delivered together, but not by control non-neutralizing anti-gp120 MAb 4.8D, indicating that NAbs could interrupt early mucosal transmission events. Frankel1998 (genital and mucosal immunity)
2G12: In a study of the influence of the glycan at position 306 of the V3 loop on MAb recognition, 2G12 was found to neutralize an HIV-BRU mutant virus that lacks the V3 loop glycan and has a mutation at the tip of the loop more efficiently than it neutralizes HIV-BRU. Schonning1998 (antibody binding site)
2G12: The complete V, J and D(H) domain was sequenced -- unlike non-neutralizing anti-gp41 MAb 3D6, five neutralizing MAbs (2F5, 2G12, 1B1, 1F7, and 3D5) showed extensive somatic mutations giving evidence of persistent antigenic pressure over long periods -- 2G12 D(H) has the best homology to a D(H) segment between D3-22 and D4-23, a region not usually considered for heavy-chain rearrangement because it lacks associated recombination signals in the flanking regions, Kunert et al. suggest this may be why Abs that compete with 2G12 are rare. Kunert1998 (antibody sequence)
2G12: Review of the antigenic and receptor binding-domains of gp120 in relation to the structure of the molecule -- MAbs are discussed by category (anti-V2, anti-V3, CD4i, CD4BS...), however as 2G12 binds to a rarely immunogenic region, and it is dependent on glycosylation, it was discussed individually. Wyatt1998a (review)
2G12: Neutralization synergy was observed when the MAbs 694/98-D (V3), 2F5 (gp41), and 2G12 (gp120 discontinuous) were used in combination, and even greater neutralizing potential was seen with the addition of a fourth MAb, F105 (CD4 BS). Li1998 (antibody interactions)
2G12: MAbs 2G12, 2F5 and b12 are broadly neutralizing, as are some human polyconal sera, but this paper describes a set of primary isolates that are resistant to all three MAbs and 2 broadly neutralizing sera -- results indicate that resistance levels of pediatric isolates might be higher than adult isolates -- resistance in general did not seem to be conferred by a loss of binding affinity for gp120 or gp41, rather by a more global perturbation of oligomeric Envelope. Parren1998a (variant cross-reactivity)
2G12: Induces complement-mediated lysis in MN but not primary isolates -- primary isolates are refractive to CML. Takefman1998 (complement, variant cross-reactivity)
2G12: Notes that 2G12 and 2F5, potent neutralizing antibodies, were identified by screening for cell surface (oligomeric Envelope) reactivity. Fouts1998 (antibody binding site)
2G12: A wide range of neutralizing titers was observed that was independent of co-receptor usage. Trkola1998 (co-receptor, variant cross-reactivity)
2G12: A panel of MAbs were shown to bind with similar or greater affinity and similar competition profiles to a deglycosylated or variable loop deleted core gp120 protein (Delta V1, V2, and V3), thus such a core protein produces a structure closely approximating full length folded monomer -- MAb 2G12 was the only exception to this, showing reduced binding efficiency. Binley1998 (antibody binding site)
2G12: Does not compete with binding of MAb generated in response to gp120-CD4 complex, CG10. Sullivan1998 (antibody interactions)
2G12: Ab from gp120 vaccinated individuals prior to infection, who subsequently became HIV infected, could not achieve 90% neutralization of the primary virus by which the individuals were ultimately infected -- these viruses were not particularly refractive to neutralization, as determined by their susceptibility to neutralization by MAbs 2G12, IgG1b12, 2F5 and 447-52D. Connor1998
2G12: Enhances Hx10 binding to CD4 positive or negative HeLa cells, but inhibited binding to CD4+ T-cell line A3.01 -- neutralizes Hx10 infection of the HeLa cells. Mondor1998
2G12: Summary of the implications of the crystal structure of gp120 combined with what is known about mutations that reduce NAb binding -- probable mechanism of neutralization by 2G12 is unknown, but dependent on proper glycosylation and 2G12 is predicted to be oriented toward the target cell when bound, so neutralization may be due to steric hindrance -- mutations in positions N 295, T 297, S 334, N 386, N 392 and N 397 HXBc2 (IIIB) decrease 2G12 binding, and the binding region is 25 angstroms from the CD4 binding site -- probably the Ab binds in part to carbohydrates, which may account for both its broad reactivity and the scarcity of Abs in the same competition group. Wyatt1998 (antibody binding site)
2G12: The MAb and Fab binding to the oligomeric form of gp120 and neutralization were highly correlated -- authors suggest that neutralization is determined by the fraction of Ab sites occupied on a virion irrespective of the epitope. Parren1998 (antibody binding site)
2G12: Post-exposure prophylaxis was effective when MAb 694/98-D was delivered 15 min post-exposure to HIV-1 LAI in hu-PBL-SCID mice, but declined to 50% if delivered 60 min post-exposure, and similar time constraints have been observed for HIVIG, 2F5 and 2G12, in contrast to MAb BAT123 that could protect when delivered 4 hours post infection. Andrus1998 (immunoprophylaxis)
2G12: Neutralizes TCLA strains and primary isolates. Parren1997 (variant cross-reactivity)
2G12: Review that discusses this MAb -- reacts with residues at the base of the V3 loop and V4, and most of the changes that reduce binding are glycosylation sites -- it is not clear whether the binding site is peptidic or direct carbohydrate. Burton1997 (antibody binding site, review)
2G12: Viral binding inhibition by 2G12 was strongly correlated with neutralization (all other neutralizing MAbs tested showed some correlation except 2F5). Ugolini1997 (antibody binding site)
2G12: Using concentrations of Abs achievable in vivo, the triple combination of 2F5, 2G12 and HIVIG was found to be synergistic to have the greatest breadth and magnitude of response against 15 clade B primary isolates. Mascola1997 (antibody interactions, variant cross-reactivity)
2G12: Review: MAbs 2F5, 2G12 and IgG1b12 have potential for use in combination with CD4-IgG2 as an immunotherapeutic or immunoprophylactic -- homologous MAbs to these are rare in humans and vaccine strategies should consider including constructs that may enhance exposure of these MAbs' epitopes. Moore1997 (immunoprophylaxis, immunotherapy, review)
2G12: One of 14 human MAbs tested for ability to neutralize a chimeric SHIV-vpu+, which expressed HIV-1 IIIB Env -- 2G12 was a strong neutralizer of SHIV-vpu+ -- all Ab combinations tested showed synergistic neutralization -- 2G12 has synergistic response with MAbs 694/98-D (anti-V3), 2F5, F105, and b12. Li1997 (antibody interactions)
2G12: Study shows neutralization is not predicted by MAb binding to JRFL monomeric gp120, but is associated with oligomeric Env binding -- 2G12 bound monomer, and weakly bound oligomer and neutralized JRFL. Fouts1997 (antibody binding site)
2G12: A JRCSF variant that was selected for IgG1b12 resistance remained sensitive to MAbs 2G12 and 2F5, for combination therapy. Mo1997 (escape)
2G12: In a multilab evaluation of monoclonal antibodies, only IgG1b12, 2G12, and 2F5 could neutralize at least half of the 9 primary test isolates at a concentration of < 25 mug per ml for 90% viral inhibition -- neutralized 6 of 9 primary isolates. DSouza1997 (variant cross-reactivity)
2G12: Review: Only four epitopes have been described which can stimulate a useful neutralizing response to a broad spectrum of primary isolates, represented by the binding sites of MAbs: 447-52-D, 2G12, Fab b12, and 2F5. Sattentau1996 (review)
2G12: Neutralizes primary isolates, HXB2, and chimeric virus with gp120 from primary isolates in an HXB2 background. McKeating1996b (variant cross-reactivity)
2G12: Neutralizes JR-FL -- inhibits gp120 interaction with CCR-5 in a MIP-1beta-CCR-5 competition study. Trkola1996b (co-receptor)
2G12: Review: exceptional capacity to neutralize primary isolates in terms of both breadth and potency -- one of three MAbs (IgG1b12, 2G12, and 2F5) generally accepted as having significant potency against primary isolates. Poignard1996 (variant cross-reactivity, review)
2G12: Review: binding site is distinct from CD4BS MAbs epitope and is unique among known gp120 MAbs, human or rodent. Moore1995c (review)
2G12: Binding weakly enhanced by some anti-C1, -C4, -V3, and CD4 binding site MAbs -- unusual in that 2G12 binding neither enhanced or inhibited the binding of other MAbs included in the study. Moore1996 (antibody interactions)
2G12: Conformationally sensitive epitope destroyed by mutations altering the N-linked glycosylation sites near the base of the V3 loop and the amino-terminal flank of the V4 loop. Trkola1996 (ADCC, antibody binding site)
2G12: Highly potent Cross-clade neutralizing activity. Trkola1995a (subtype comparisons)
2G12: Human MAb generated by electrofusion of PBL from HIV-1+ volunteers with CB-F7 cells. Buchacher1994 (antibody generation)

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