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Displaying record number 2460

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MAb ID	HJ16 (HJ16_22)
HXB2 Location	gp160	gp160 Epitope Map
Author Location	gp120
Epitope
Subtype	C
Ab Type	gp120 CD4BS
Neutralizing	P View neutralization details
Contacts and Features	View contacts and features
Species (Isotype)	human(IgG1)
Patient	VI3208
Immunogen	HIV-1 infection
Keywords	adjuvant comparison, antibody binding site, antibody gene transfer, antibody generation, antibody interactions, antibody lineage, antibody polyreactivity, antibody sequence, assay or method development, binding affinity, broad neutralizer, computational epitope prediction, escape, glycosylation, immunoprophylaxis, memory cells, neutralization, optimal epitope, polyclonal antibodies, review, structure, subtype comparisons, vaccine antigen design, vaccine-induced immune responses, variant cross-reactivity

Notes

Showing 47 of 47 notes.

HJ16: 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. HJ16-Env formed a distinct group within the CD4bs category, Class HJ16. Crystal structure data on HJ16 complexed to HIV-1 gp120 was found in PDB ID: 4YE4. Chuang2019 (antibody binding site, antibody interactions, neutralization, binding affinity, antibody sequence, structure, antibody lineage, broad neutralizer)
HJ16: 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)
HJ16: 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. HJ16 was used for analyzing clade sensitivity and the CD4b signature summaries. Bricault2019 (antibody binding site, vaccine antigen design, computational epitope prediction, broad neutralizer)
HJ16: 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 HJ16 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)
HJ16: In the RV305 HIV-1 vaccine trial, two boosts of either ALVAC-HIV, AIDSVAX B/E gp120 or ALVAC-HIV + AIDSVAX B/E gp120 were given to HIV-1-uninfected RV144 vaccine-recipients. While no bNAb plasma activity was induced in this trial as well, an increased frequency of memory B cells that produce Env-specific anti-CD4bs antibodies with long HCDR3s was detected. HJ16 binding to the N276A mutant of CRF01_AE Env protein A244 was reduced to 1% as compared to wt. Easterhoff2017 (binding affinity)
HJ16: 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)
HJ16: 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)
HJ16: 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)
HJ16: 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. HJ16 was used as a reference Ab. Crooks2015 (glycosylation, neutralization)
HJ16: This review classified and mapped the binding regions of 32 bNAbs isolated 2010-2016. Wu2016 (review)
HJ16: 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)
HJ16: 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-CD4bs bNAb HJ16 to trimers was minimally affected by trimer cross-linking. Schiffner2016 (assay or method development, binding affinity, structure)
HJ16: 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-CD4bs bNAb HJ16 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)
HJ16: 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. HJ16, a CD4bs bnAb belonged to a group with slopes >1. Webb2015 (neutralization)
HJ16: Donor EB179 was a long-term non-progressor with high serum neutralization breadth and potency. 8 B-cell clones produced antibodies of which 179NC75 had the highest neutralization, especially to Clade B virus, neutralizing 70% of a clade-B pseudovirus panel and 6 out of 9 cross-clade Env pseudoviruses as opposed to bNAb HJ16's neutralizing 3/9 of the same psuedoviral panel. 179NC75 was also more potent than HJ16 against 15 viruses of a 22 Tier-2 clade B panel. Binding studies revealed that 179NC75 is a glycan-dependent antibody that binds to the CD4bs in a way that involves the Asn276 residue and depends on the presence of complex glycans, in contrast to most CD4bs bNAbs which belong to the VRC01 class. It belongs to the same sub-class of CDRH3-dominated CD4bs antibodies as HJ16. Freund2015 (neutralization)
HJ16: This study isolated 4 novel antibodies that bind the CD4 binding site of Env. Population-level analysis classified a diverse group of CD4bs antibodies into two types: CDR H3-dominated or VH-gene-restricted, each with distinct ontogenies. Structural data revealed that neutralization breadth was correlated with angle of approach of the antibodies to the CD4 binding region. HJ16 was one of the antibodies in the CDR H3-dominated class. Zhou2015 (neutralization, structure, antibody lineage, broad neutralizer)
HJ16: 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)
HJ16: CD4-binding site Abs are reviewed. New insights from donor-serum responses, atomic-level structures of antibody-Env complexes, and next-generation sequencing of B-cell transcripts are invigorating vaccine-design efforts to elicit effective CD4-binding site Abs. Analysis of the epitopes recognized by CD4-binding Abs reveals substantial similarity in the recognized region of gp120. HJ16 is canonical CDR3H3 utilizer and targets outer domain of gp120 Georgiev2013a (review)
HJ16: This study examined the development and co-evolution of autologous antibodies and viruses in two patients. Antibodies with limited heterologous breadth were able to potently neutralize autologous viruses, and such antibodies could select for neutralization-resistant autologous viruses implicated in transmission. Viruses from subject CH0457 were largely susceptible to neutralization by CD4bs-binding heterologous nAbs CH31 and CH106. The CD4bs CH27 lineage mAbs from subject CH0457 were similar to HJ16, which neutralizes multiple tier 2 but not tier 1 viruses. Glycan-dependent HJ16 potently neturalized 6.9% of an 84-psuedoviral panel amplified from CH0457. Moody2015 (neutralization)
HJ16: 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)
HJ16: 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)
HJ16: 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. HJ16 is a CD4bs Ab, with breadth 30%, IC₅₀ 0.77 μg per ml, and its unique feature is extensive affinity maturation. Kwong2013 (review)
HJ16: 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)
HJ16: N276D was determined as the critical binding site of MAb HJ16 by resistance induction in a sensitive primary CRF02_AG strain. N-linked glycosylation site removing N276D mutation was responsible for resistance to HJ16 by site-directed mutagenesis in envs of the homologous CRF02_AG, as well as of a subtype A and a subtype C primary isolate. The effect of N276D was very selective, as it failed to confer resistance to a range of other entry inhibitors. Sensitivity to the CD4bs VRC01 and VRC03 mAbs was increased in the N276D mutated viruses. These data indicate that binding of the CD4bs specific HJ16 mAb critically depends on the interaction with the N276-glycan, thus indicating that HJ16 is the first glycan dependent CD4bs-specific mAb. Balla-Jhagjhoorsingh2013 (antibody binding site, glycosylation)
HJ16: "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)
HJ16: 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. HJ16 was used as a CD4bs MAb to compare neutralizing specificity of VRC06. Li2012
HJ16: 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 CD4-binding site, type not yet determined, HJ16 class, HJ16 family. Kwong2012 (review, structure, broad neutralizer)
HJ16: This review discusses how analysis of infection and vaccine candidate-induced antibodies and their genes may guide vaccine design. This MAb is listed as cross-reactive neutralizing antibody, binding near CD4 binding site isolated after 2009 by neutralization screening of cultured, unselected IgG+ memory B cells. Bonsignori2012b (vaccine antigen design, vaccine-induced immune responses, review)
HJ16: 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. HJ16, which recognizes the core epitope, was among the 17 bnAbs which were used in studying the mutations in FWR. Klein2013 (neutralization, structure, antibody lineage)
HJ16: This study shows that Env immunogens fail to engage the germline-reverted forms of known bnAbs that target CD4BS. However, the elimination of a conserved NLGS at Asn276 in Loop D and the NLGS at positions 460 and 463, located in variable region 5 of Env increased the binding and activation of VRC01 and NIH45-46. HJ16 was referred to as anti-CD4BS bnAbs. McGuire2013 (neutralization, antibody lineage)
HJ16: 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. HJ16 has been discussed as NAb against CD4BS. Kovacs2012 (antibody binding site, neutralization, binding affinity)
HJ16: 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. HJ16 has been referred in discussing the breadth and potency of antiCD4 abs. West2012a (antibody lineage)
HJ16: The use of computationally derived B cell clonal lineages as templates for HIV-1 immunogen design is discussed. HJ16 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)
HJ16: Polyclonal B cell responses to conserved neutralization epitopes are reported. Cross-reactive plasma samples were identified and evaluated from 308 subjects tested. HJ16 was used as a control mAb in the comprehensive set of assays performed. Tomaras2011 (neutralization, polyclonal antibodies)
HJ16: 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. HJ16 has been referred as gp120 binding Ab isolated from Clade C infected patients. Mouquet2011 (neutralization)
hj16: The strategy of incorporating extra glycans onto gp120 was explored, with the goal to occlude the epitopes of non-neutralizing MAbs while maintaining exposure of the b12 site. The focus was on the head-to-head comparison of the ability of 2 adjuvants, monophosphoryl lipid A (MPL) and Quil A, to promote CD4-specific Ab responses in mice immunized with the engineered mutant Q105N compared to gp120wt. Neutralizing and non-neutralizing antibodies targeting three areas on gp120 – the CD4bs (F105, b6, b12, b13, VRC01, VRC03 and CD4- IgG2), the glycosylated ‘silent face’ (2G12) and the V3 loop (B4e8) – were assessed for binding. The antibodies b6, b12, b13, VRC01 and 2G12 bound best to mutant Q105N, albeit with lower affinities than to gp120wt. Retention of b6 and b13 binding was not expected, but can be explained by their very similar mode of interaction with the CD4bs compared to b12. Abs F105 and VRC03 did not bind Q105N at all. The V3-specific antibody B4e8 did not bind to Q105N. Ahmed2012 (adjuvant comparison, antibody binding site, glycosylation, neutralization, escape)
HJ16: 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)
HJ16: 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. HJ16 strongly bound to RSC3/G367R, weakly bound to gp120 core, gp120 core D368R, RSC3 and RSC3 Δ3711, and very weakly bound to RSC3 Δ3711/P363N. Lynch2012 (binding affinity)
HJ16: Characteristics of the patients' plasma and their respective mAbs in multiple neutralization assay formats was presented. HJ16 MAb neutralized the subtype C isolate VI829, the subtype D CI 13 and two of the three CRF02_AG isolates, VI 1090 and CA18 against a panel of 17 primary viruses belonging to 6 subtypes in the 24/1/14 extended incubation PBMC assay. In another experiment, out of the 12 isolates, HJ16 MAb neutralized four in 24/1/14 PBMC assays, three in 1/2/7 PBMC assays, one in 1/24/14 PBMC assays, two in TZMbl_IV assays, three in TZMbl_PV assays and four in GHOST_PV assays. When evaluating plasma vs. Ab in the TZMbl pseudovirus assay, HJ16 MAb was not able to neutralize the three tier 1 strains but neutralized seven out of eleven Tier 2 strains. Balla-Jhagjhoorsingh2011 (neutralization, subtype comparisons)
HJ16: Two SHIV-C mutants were designed: SHIV-1157ipEL-pΔ3N, a mutant of the early SHIV-1157ipEL-p which lacked the 3N residues in the V2 stem, and SHIV-1157ipd3N4+3N, a mutant of the late SHIV-1157ipd3N4 where 3N residues was added in the V2 stem. nMAb HJ16 neutralized neither early nor late SHIV-Cs indicating that the HJ16 epitope may not be present on the SHIV-C envelopes. Watkins2011 (neutralization)
HJ16: 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)
HJ16: 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 neutralizes a multi-clade panel of pseudoviruses with a breadth comparable to b12. Gonzalez2010 (neutralization, variant cross-reactivity, escape, review)
HJ16: 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 was mentioned in the context of immunogens based on the epitopes recognized by bNAbs. HJ16 exhibited similar breadth and potency as b12 but showed a different pattern of neutralization sensitivity. Walker2010a (neutralization, review)
HJ16: 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)
HJ16: 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)
HJ16: This Ab was sensitive to mutations D474A, R476A and M475A/R476A but not to D368A, indicating that HJ16 targets the same epitope as anti-core Abs. It is suggested that HJ16 and anti-core Abs bind to a conformational epitope including the α5 helix at the outer-domain-inner-domain junction of gp120. This epitope was highly conserved across different HIV-1 isolates. Pietzsch2010a (antibody binding site, optimal epitope, binding affinity)
HJ16: This MAb was isolated from memory B cells of HIV-1 infected donor using an improved EBV immortalization method combined with a broad screening strategy. HJ16 bound to Env proteins from clades AE, AG, B and BC. The discontinuous epitope of this Ab was located in the proximity of the CD4bs b12 epitope but did not overlap with the b12 epitope. HJ16 showed broad neutralizing activity that was comparable to that of mAbs b12 and 2F5 and superior to that of mAbs 2G12 and 447-52D. HJ16 neutralized 1/10 Tier 1 and 32/82 Tier 2 viruses and did not discriminate between clades as much as mAbs b12, 2G12 and 2F5. HJ16 and b12 showed non-overlapping patterns of neutralizing activity. Corti2010 (antibody generation, neutralization, variant cross-reactivity, binding affinity, subtype comparisons)

References

Showing 48 of 48 references.

Isolation Paper
Corti2010 Davide Corti, Johannes P. M. Langedijk, Andreas Hinz, Michael S. Seaman, Fabrizia Vanzetta, Blanca M. Fernandez-Rodriguez, Chiara Silacci, Debora Pinna, David Jarrossay, Sunita Balla-Jhagjhoorsingh, Betty Willems, Maria J. Zekveld, Hanna Dreja, Eithne O'Sullivan, Corinna Pade, Chloe Orkin, Simon A. Jeffs, David C. Montefiori, David Davis, Winfried Weissenhorn, Áine McKnight, Jonathan L. Heeney, Federica Sallusto, Quentin J. Sattentau, Robin A. Weiss, and Antonio Lanzavecchia. Analysis of Memory B Cell Responses and Isolation of Novel Monoclonal Antibodies with Neutralizing Breadth from HIV-1-Infected Individuals. PLoS One, 5(1):e8805, 2010. PubMed ID: 20098712. Show all entries for this paper.

Ahmed2012 Fatima K. Ahmed, Brenda E. Clark, Dennis R. Burton, and Ralph Pantophlet. An Engineered Mutant of HIV-1 gp120 Formulated with Adjuvant Quil A Promotes Elicitation of Antibody Responses Overlapping the CD4-Binding Site. Vaccine, 30(5):922-930, 20 Jan 2012. PubMed ID: 22142583. Show all entries for this paper.

Balla-Jhagjhoorsingh2011 Sunita S. Balla-Jhagjhoorsingh, Betty Willems, Liesbeth Heyndrickx, Leo Heyndrickx, Katleen Vereecken, Wouter Janssens, Michael S. Seaman, Davide Corti, Antonio Lanzavecchia, David Davis, and Guido Vanham. Characterization of Neutralizing Profiles in HIV-1 Infected Patients from Whom the HJ16, HGN194 and HK20 mAbs Were Obtained. PLoS One, 6(10):e25488, 2011. PubMed ID: 22016769. Show all entries for this paper.

Balla-Jhagjhoorsingh2013 Sunita S. Balla-Jhagjhoorsingh, Davide Corti, Leo Heyndrickx, Elisabeth Willems, Katleen Vereecken, David Davis, and Guido Vanham. The N276 Glycosylation Site Is Required for HIV-1 Neutralization by the CD4 Binding Site Specific HJ16 Monoclonal Antibody. PLoS One, 8(7):e68863, 2013. PubMed ID: 23874792. Show all entries for this paper.

Bonsignori2012b Mattia Bonsignori, S. Munir Alam, Hua-Xin Liao, Laurent Verkoczy, Georgia D. Tomaras, Barton F. Haynes, and M. Anthony Moody. HIV-1 Antibodies from Infection and Vaccination: Insights for Guiding Vaccine Design. Trends Microbiol., 20(11):532-539, Nov 2012. PubMed ID: 22981828. Show all entries for this paper.

Braibant2013 Martine Braibant, Eun-Yeung Gong, Jean-Christophe Plantier, Thierry Moreau, Elodie Alessandri, François Simon, and Francis Barin. Cross-Group Neutralization of HIV-1 and Evidence for Conservation of the PG9/PG16 Epitopes within Divergent Groups. AIDS, 27(8):1239-1244, 15 May 2013. PubMed ID: 23343910. Show all entries for this paper.

Bricault2019 Christine A. Bricault, Karina Yusim, Michael S. Seaman, Hyejin Yoon, James Theiler, Elena E. Giorgi, Kshitij Wagh, Maxwell Theiler, Peter Hraber, Jennifer P. Macke, Edward F. Kreider, Gerald H. Learn, Beatrice H. Hahn, Johannes F. Scheid, James M. Kovacs, Jennifer L. Shields, Christy L. Lavine, Fadi Ghantous, Michael Rist, Madeleine G. Bayne, George H. Neubauer, Katherine McMahan, Hanqin Peng, Coraline Chéneau, Jennifer J. Jones, Jie Zeng, Christina Ochsenbauer, Joseph P. Nkolola, Kathryn E. Stephenson, Bing Chen, S. Gnanakaran, Mattia Bonsignori, LaTonya D. Williams, Barton F. Haynes, Nicole Doria-Rose, John R. Mascola, David C. Montefiori, Dan H. Barouch, and Bette Korber. HIV-1 Neutralizing Antibody Signatures and Application to Epitope-Targeted Vaccine Design. Cell Host Microbe, 25(1):59-72.e8, 9 Jan 2019. PubMed ID: 30629920. Show all entries for this paper.

Burton2010 Dennis R. Burton and Robin A. Weiss. A Boost for HIV Vaccine Design. Science, 329(5993):770-773, 13 Aug 2010. PubMed ID: 20705840. Show all entries for this paper.

Chuang2019 Gwo-Yu Chuang, Jing Zhou, Priyamvada Acharya, Reda Rawi, Chen-Hsiang Shen, Zizhang Sheng, Baoshan Zhang, Tongqing Zhou, Robert T. Bailer, Venkata P. Dandey, Nicole A. Doria-Rose, Mark K. Louder, Krisha McKee, John R. Mascola, Lawrence Shapiro, and Peter D. Kwong. Structural Survey of Broadly Neutralizing Antibodies Targeting the HIV-1 Env Trimer Delineates Epitope Categories and Characteristics of Recognition. Structure, 27(1):196-206.e6, 2 Jan 2019. PubMed ID: 30471922. 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.

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.

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.

Easterhoff2017 David Easterhoff, M. Anthony Moody, Daniela Fera, Hao Cheng, Margaret Ackerman, Kevin Wiehe, Kevin O. Saunders, Justin Pollara, Nathan Vandergrift, Rob Parks, Jerome Kim, Nelson L. Michael, Robert J. O'Connell, Jean-Louis Excler, Merlin L. Robb, Sandhya Vasan, Supachai Rerks-Ngarm, Jaranit Kaewkungwal, Punnee Pitisuttithum, Sorachai Nitayaphan, Faruk Sinangil, James Tartaglia, Sanjay Phogat, Thomas B. Kepler, S. Munir Alam, Hua-Xin Liao, Guido Ferrari, Michael S. Seaman, David C. Montefiori, Georgia D. Tomaras, Stephen C. Harrison, and Barton F. Haynes. Boosting of HIV Envelope CD4 Binding Site Antibodies with Long Variable Heavy Third Complementarity Determining Region in the Randomized Double Blind RV305 HIV-1 Vaccine Trial. PLoS Pathog., 13(2):e1006182, Feb 2017. PubMed ID: 28235027. Show all entries for this paper.

Feng2012 Yu Feng, Krisha McKee, Karen Tran, Sijy O'Dell, Stephen D. Schmidt, Adhuna Phogat, Mattias N. Forsell, Gunilla B. Karlsson Hedestam, John R. Mascola, and Richard T. Wyatt. Biochemically Defined HIV-1 Envelope Glycoprotein Variant Immunogens Display Differential Binding and Neutralizing Specificities to the CD4-Binding Site. J. Biol. Chem., 287(8):5673-5686, 17 Feb 2012. PubMed ID: 22167180. Show all entries for this paper.

Freund2015 Natalia T. Freund, Joshua A. Horwitz, Lilian Nogueira, Stuart A. Sievers, Louise Scharf, Johannes F. Scheid, Anna Gazumyan, Cassie Liu, Klara Velinzon, Ariel Goldenthal, Rogier W. Sanders, John P. Moore, Pamela J. Bjorkman, Michael S. Seaman, Bruce D. Walker, Florian Klein, and Michel C. Nussenzweig. A New Glycan-Dependent CD4-Binding Site Neutralizing Antibody Exerts Pressure on HIV-1 In Vivo. PLoS Pathog, 11(10):e1005238, Oct 2015. PubMed ID: 26516768. Show all entries for this paper.

Georgiev2013 Ivelin S. Georgiev, Nicole A. Doria-Rose, Tongqing Zhou, Young Do Kwon, Ryan P. Staupe, Stephanie Moquin, Gwo-Yu Chuang, Mark K. Louder, Stephen D. Schmidt, Han R. Altae-Tran, Robert T. Bailer, Krisha McKee, Martha Nason, Sijy O'Dell, Gilad Ofek, Marie Pancera, Sanjay Srivatsan, Lawrence Shapiro, Mark Connors, Stephen A. Migueles, Lynn Morris, Yoshiaki Nishimura, Malcolm A. Martin, John R. Mascola, and Peter D. Kwong. Delineating Antibody Recognition in Polyclonal Sera from Patterns of HIV-1 Isolate Neutralization. Science, 340(6133):751-756, 10 May 2013. PubMed ID: 23661761. Show all entries for this paper.

Georgiev2013a Ivelin S. Georgiev, M. Gordon Joyce, Tongqing Zhou, and Peter D. Kwong. Elicitation of HIV-1-Neutralizing Antibodies against the CD4-Binding Site. Curr. Opin. HIV AIDS, 8(5):382-392, Sep 2013. PubMed ID: 23924998. Show all entries for this paper.

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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.

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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.

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McGuire2013 Andrew T. McGuire, Sam Hoot, Anita M. Dreyer, Adriana Lippy, Andrew Stuart, Kristen W. Cohen, Joseph Jardine, Sergey Menis, Johannes F. Scheid, Anthony P. West, William R. Schief, and Leonidas Stamatatos. Engineering HIV Envelope Protein To Activate Germline B Cell Receptors of Broadly Neutralizing Anti-CD4 Binding Site Antibodies. J. Exp. Med., 210(4):655-663, 8 Apr 2013. PubMed ID: 23530120. Show all entries for this paper.

Moody2015 M. Anthony Moody, Feng Gao, Thaddeus C. Gurley, Joshua D. Amos, Amit Kumar, Bhavna Hora, Dawn J. Marshall, John F. Whitesides, Shi-Mao Xia, Robert Parks, Krissey E. Lloyd, Kwan-Ki Hwang, Xiaozhi Lu, Mattia Bonsignori, Andrés Finzi, Nathan A. Vandergrift, S. Munir Alam, Guido Ferrari, Xiaoying Shen, Georgia D. Tomaras, Gift Kamanga, Myron S. Cohen, Noel E. Sam, Saidi Kapiga, Elin S. Gray, Nancy L. Tumba, Lynn Morris, Susan Zolla-Pazner, Miroslaw K. Gorny, John R. Mascola, Beatrice H. Hahn, George M. Shaw, Joseph G. Sodroski, Hua-Xin Liao, David C. Montefiori, Peter T. Hraber, Bette T. Korber, and Barton F. Haynes. Strain-Specific V3 and CD4 Binding Site Autologous HIV-1 Neutralizing Antibodies Select Neutralization-Resistant Viruses. Cell Host Microbe., 18(3):354-362, 9 Sep 2015. PubMed ID: 26355218. Show all entries for this paper.

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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.

Sattentau2010 Quentin J. Sattentau and Andrew J. McMichael. New Templates for HIV-1 Antibody-Based Vaccine Design. F1000 Biol. Rep., 2:60, 2010. PubMed ID: 21173880. Show all entries for this paper.

Schiffner2016 Torben Schiffner, Natalia de Val, Rebecca A. Russell, Steven W. de Taeye, Alba Torrents de la Peña, Gabriel Ozorowski, Helen J. Kim, Travis Nieusma, Florian Brod, Albert Cupo, Rogier W. Sanders, John P. Moore, Andrew B. Ward, and Quentin J. Sattentau. Chemical Cross-Linking Stabilizes Native-Like HIV-1 Envelope Glycoprotein Trimer Antigens. J. Virol., 90(2):813-828, 28 Oct 2015. PubMed ID: 26512083. 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.

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.

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.

Tomaras2011 Georgia D. Tomaras, James M. Binley, Elin S. Gray, Emma T. Crooks, Keiko Osawa, Penny L. Moore, Nancy Tumba, Tommy Tong, Xiaoying Shen, Nicole L. Yates, Julie Decker, Constantinos Kurt Wibmer, Feng Gao, S. Munir Alam, Philippa Easterbrook, Salim Abdool Karim, Gift Kamanga, John A. Crump, Myron Cohen, George M. Shaw, John R. Mascola, Barton F. Haynes, David C. Montefiori, and Lynn Morris. Polyclonal B Cell Responses to Conserved Neutralization Epitopes in a Subset of HIV-1-Infected Individuals. J. Virol., 85(21):11502-11519, Nov 2011. PubMed ID: 21849452. 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.

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Webb2015 Nicholas E. Webb, David C. Montefiori, and Benhur Lee. Dose-Response Curve Slope Helps Predict Therapeutic Potency and Breadth of HIV Broadly Neutralizing Antibodies. Nat. Commun., 6:8443, 29 Sep 2015. PubMed ID: 26416571. Show all entries for this paper.

West2012a Anthony P. West, Jr., Ron Diskin, Michel C. Nussenzweig, and Pamela J. Bjorkman. Structural Basis for Germ-Line Gene Usage of a Potent Class of Antibodies Targeting the CD4-Binding Site of HIV-1 gp120. Proc. Natl. Acad. Sci. U.S.A., 109(30):E2083-E2090, 24 Jul 2012. PubMed ID: 22745174. 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.

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.

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.

Zhou2015 Tongqing Zhou, Rebecca M. Lynch, Lei Chen, Priyamvada Acharya, Xueling Wu, Nicole A. Doria-Rose, M. Gordon Joyce, Daniel Lingwood, Cinque Soto, Robert T. Bailer, Michael J. Ernandes, Rui Kong, Nancy S. Longo, Mark K. Louder, Krisha McKee, Sijy O'Dell, Stephen D. Schmidt, Lillian Tran, Zhongjia Yang, Aliaksandr Druz, Timothy S. Luongo, Stephanie Moquin, Sanjay Srivatsan, Yongping Yang, Baoshan Zhang, Anqi Zheng, Marie Pancera, Tatsiana Kirys, Ivelin S. Georgiev, Tatyana Gindin, Hung-Pin Peng, An-Suei Yang, NISC Comparative Sequencing Program, James C. Mullikin, Matthew D. Gray, Leonidas Stamatatos, Dennis R. Burton, Wayne C. Koff, Myron S. Cohen, Barton F. Haynes, Joseph P. Casazza, Mark Connors, Davide Corti, Antonio Lanzavecchia, Quentin J. Sattentau, Robin A. Weiss, Anthony P. West, Jr., Pamela J. Bjorkman, Johannes F. Scheid, Michel C. Nussenzweig, Lawrence Shapiro, John R. Mascola, and Peter D. Kwong. Structural Repertoire of HIV-1-Neutralizing Antibodies Targeting the CD4 Supersite in 14 Donors. Cell, 161(6):1280-1292, 4 Jun 2015. PubMed ID: 26004070. 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.

Displaying record number 2124

Download this epitope record as JSON.

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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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.

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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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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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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.

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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.

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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.

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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.

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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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Liu2014 Pinghuang Liu, Latonya D. Williams, Xiaoying Shen, Mattia Bonsignori, Nathan A. Vandergrift, R. Glenn Overman, M. Anthony Moody, Hua-Xin Liao, Daniel J. Stieh, Kerrie L. McCotter, Audrey L. French, Thomas J. Hope, Robin Shattock, Barton F. Haynes, and Georgia D. Tomaras. Capacity for Infectious HIV-1 Virion Capture Differs by Envelope Antibody Specificity. J. Virol., 88(9):5165-5170, May 2014. PubMed ID: 24554654. Show all entries for this paper.

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.

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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.

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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.

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.

Nkolola2014 Joseph P. Nkolola, Christine A. Bricault, Ann Cheung, Jennifer Shields, James Perry, James M. Kovacs, Elena Giorgi, Margot van Winsen, Adrian Apetri, Els C. M. Brinkman-van der Linden, Bing Chen, Bette Korber, Michael S. Seaman, and Dan H. Barouch. Characterization and Immunogenicity of a Novel Mosaic M HIV-1 gp140 Trimer. J. Virol., 88(17):9538-9552, 1 Sep 2014. PubMed ID: 24965452. 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.

Pantophlet2010 Ralph Pantophlet. Antibody Epitope Exposure and Neutralization of HIV-1. Curr. Pharm. Des., 16(33):3729-3743, 2010. PubMed ID: 21128886. Show all entries for this paper.

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.

Pejchal2011 Robert Pejchal, Katie J. Doores, Laura M. Walker, Reza Khayat, Po-Ssu Huang, Sheng-Kai Wang, Robyn L. Stanfield, Jean-Philippe Julien, Alejandra Ramos, Max Crispin, Rafael Depetris, Umesh Katpally, Andre Marozsan, Albert Cupo, Sebastien Maloveste, Yan Liu, Ryan McBride, Yukishige Ito, Rogier W. Sanders, Cassandra Ogohara, James C. Paulson, Ten Feizi, Christopher N. Scanlan, Chi-Huey Wong, John P. Moore, William C. Olson, Andrew B. Ward, Pascal Poignard, William R. Schief, Dennis R. Burton, and Ian A. Wilson. A Potent and Broad Neutralizing Antibody Recognizes and Penetrates the HIV Glycan Shield. Science, 334(6059):1097-1103, 25 Nov 2011. PubMed ID: 21998254. Show all entries for this paper.

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.

Provine2012 Nicholas M. Provine, Valerie Cortez, Vrasha Chohan, and Julie Overbaugh. The Neutralization Sensitivity of Viruses Representing Human Immunodeficiency Virus Type 1 Variants of Diverse Subtypes from Early in Infection Is Dependent on Producer Cell, as Well as Characteristics of the Specific Antibody and Envelope Variant. Virology, 427(1):25-33, 25 May 2012. PubMed ID: 22369748. Show all entries for this paper.

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.

Qi2016 Yifei Qi, Sunhwan Jo, and Wonpil Im. Roles of Glycans in Interactions between gp120 and HIV Broadly Neutralizing Antibodies. Glycobiology, 26(3):251-260, Mar 2016. PubMed ID: 26537503. Show all entries for this paper.

Rademeyer2016 Cecilia Rademeyer, Bette Korber, Michael S. Seaman, Elena E. Giorgi, Ruwayhida Thebus, Alexander Robles, Daniel J. Sheward, Kshitij Wagh, Jetta Garrity, Brittany R. Carey, Hongmei Gao, Kelli M. Greene, Haili Tang, Gama P. Bandawe, Jinny C. Marais, Thabo E. Diphoko, Peter Hraber, Nancy Tumba, Penny L. Moore, Glenda E. Gray, James Kublin, M. Juliana McElrath, Marion Vermeulen, Keren Middelkoop, Linda-Gail Bekker, Michael Hoelscher, Leonard Maboko, Joseph Makhema, Merlin L. Robb, Salim Abdool Karim, Quarraisha Abdool Karim, Jerome H. Kim, Beatrice H. Hahn, Feng Gao, Ronald Swanstrom, Lynn Morris, David C. Montefiori, and Carolyn Williamson. Features of Recently Transmitted HIV-1 Clade C Viruses that Impact Antibody Recognition: Implications for Active and Passive Immunization. PLoS Pathog., 12(7):e1005742, Jul 2016. PubMed ID: 27434311. Show all entries for this paper.

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.

Rolland2012 Morgane Rolland, Paul T. Edlefsen, Brendan B. Larsen, Sodsai Tovanabutra, Eric Sanders-Buell, Tomer Hertz, Allan C. deCamp, Chris Carrico, Sergey Menis, Craig A. Magaret, Hasan Ahmed, Michal Juraska, Lennie Chen, Philip Konopa, Snehal Nariya, Julia N. Stoddard, Kim Wong, Hong Zhao, Wenjie Deng, Brandon S. Maust, Meera Bose, Shana Howell, Adam Bates, Michelle Lazzaro, Annemarie O'Sullivan, Esther Lei, Andrea Bradfield, Grace Ibitamuno, Vatcharain Assawadarachai, Robert J. O'Connell, Mark S. deSouza, Sorachai Nitayaphan, Supachai Rerks-Ngarm, Merlin L. Robb, Jason S. McLellan, Ivelin Georgiev, Peter D. Kwong, Jonathan M. Carlson, Nelson L. Michael, William R. Schief, Peter B. Gilbert, James I. Mullins, and Jerome H. Kim. Increased HIV-1 Vaccine Efficacy against Viruses with Genetic Signatures in Env V2. Nature, 490(7420):417-420, 18 Oct 2012. PubMed ID: 22960785. Show all entries for this paper.

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.

Sajadi2012 Mohammad M. Sajadi, George K. Lewis, Michael S. Seaman, Yongjun Guan, Robert R. Redfield, and Anthony L. DeVico. Signature Biochemical Properties of Broadly Cross-Reactive HIV-1 Neutralizing Antibodies in Human Plasma. J. Virol., 86(9):5014-5025, May 2012. PubMed ID: 22379105. Show all entries for this paper.

Sanchez-Merino2016 V. Sanchez-Merino, A. Fabra-Garcia, N. Gonzalez, D. Nicolas, A. Merino-Mansilla, C. Manzardo, J. Ambrosioni, A. Schultz, A. Meyerhans, J. R. Mascola, J. M. Gatell, J. Alcami, J. M. Miro, and E. Yuste. Detection of Broadly Neutralizing Activity within the First Months of HIV-1 Infection. J. Virol., 90(11):5231-5245, 1 Jun 2016. PubMed ID: 26984721. Show all entries for this paper.

Scott2015 Yanille M. Scott, Seo Young Park, and Charlene S. Dezzutti. Broadly Neutralizing Anti-HIV Antibodies Prevent HIV Infection of Mucosal Tissue Ex Vivo. Antimicrob. Agents Chemother., 60(2):904-912, Feb 2016. PubMed ID: 26596954. Show all entries for this paper.

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.

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.

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.

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.

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.

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.

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.

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.

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Displaying record number 3488

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MAb ID	VRC18b
HXB2 Location	gp160	gp160 Epitope Map
Author Location
Epitope
Ab Type
Neutralizing
Contacts and Features	View contacts and features
Species (Isotype)
Patient
Immunogen
Keywords	antibody binding site, glycosylation, structure

Notes

Showing 1 of 1 note.

VRC18b: 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)

References

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Displaying record number 2651

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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

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PGT145: The crystal structure of Fab NC-Cow1 was determined.The NC-Cow1 structure was then determined in a quaternary complex with BG505 SOSIP.664, in which human Fabs PGT128 and 35022 were added to facilitate formation of diffraction-quality crystals. The exceptionally long (60 residues) CDR H3 of the heavy chain of NC-Cow1 forms a mini domain (knob) on an extended stalk that navigates through the dense glycan shield on Env to target a small footprint on the gp120 CD4 receptor binding site with no contact of the other CDRs to the rest of the Env trimer. The 3D structure of NC-Cow1 was closely compared with that of PGT145. Stanfield2020 (structure)
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 3147

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MAb ID	35O22 (35022)
HXB2 Location	gp160	gp160 Epitope Map
Author Location
Epitope	(Discontinuous epitope)
Subtype	B
Ab Type	gp41-gp41 interface
Neutralizing	P (tier 2) View neutralization details
Contacts and Features	View contacts and features
Species (Isotype)	human(IgG)
Patient	Donor N152
Immunogen	HIV-1 infection
Keywords	antibody binding site, antibody generation, antibody interactions, antibody lineage, antibody sequence, assay or method development, binding affinity, broad neutralizer, computational epitope prediction, elite controllers, escape, glycosylation, immunoprophylaxis, neutralization, polyclonal antibodies, review, structure, subtype comparisons, vaccine antigen design, vaccine-induced immune responses

Notes

Showing 31 of 31 notes.

35022: The crystal structure of Fab NC-Cow1 was determined. The NC-Cow1 structure was then determined in a quaternary complex with BG505 SOSIP.664, in which human Fabs PGT128 and 35022 were added to facilitate formation of diffraction-quality crystals. The exceptionally long (60 residues) CDR H3 of the heavy chain of NC-Cow1 forms a mini domain (knob) on an extended stalk that navigates through the dense glycan shield on Env to target a small footprint on the gp120 CD4 receptor binding site with no contact of the other CDRs to the rest of the Env trimer. Stanfield2020 (structure)
35O22: 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. 35O22-Env formed a distinct group within the Subunit Interface category, Class 35O22. Data for 35O22 complexed to (i) Clade G X1193.ct SOSIP.664 prefusion trimer as a 3.4A resolution crystal structure was found in PDB ID: 5FYJ; (ii) Clade A BG505 SOSIP.664 trimer was found in PDB ID: 5FYL; and (iii) PDB ID: 5CEZ. Chuang2019 (antibody binding site, antibody interactions, neutralization, binding affinity, antibody sequence, structure, antibody lineage, broad neutralizer)
35O22: 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)
35O22: 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. 35O22 broadly neutralized HIV-1AD8 full-length and cytoplasmic tail-deleted Envs. Castillo-Menendez2019 (vaccine antigen design, structure)
35O22: 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 gp120-gp41 interface recognized by PGT151 and 35O22, 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)
35O22: 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. 35O22 was used as a reference Ab. Crooks2015 (glycosylation, neutralization)
35O22: This review discusses how the identification of super-antibodies, where and how such antibodies may be best applied and future directions for the field. 35O22, a prototype super-Ab, was isolated from human B cell clones. Antigenic region gp120–gp41 interface (Table:1). Walker2018 (antibody binding site, review, broad neutralizer)
35O22: 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)
35O22: 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 35O22 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)
35O22: 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-gp41-gp120 interface NAb 35O22, binds at a fraction of the binding of 2G12 to Env-ND, and this binding is insensitive to glutaraldehyde treatment . Witt2017 (vaccine antigen design, binding affinity)
35O22: 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. 35O22 recognizes this trimer antigenically. Chuang2017 (antibody interactions)
35O22: 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)
35O22: 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, structure)
35O22: 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)
35O22: 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)
35O22: A weakly neutralizing antibody was isolated, CAP248-2B. The glycan dependence of CAP248-2B was compared to other known gp120-gp41 interface targeting bNAbs (8ANC195, 35O22, PGT151, 3BC315). CAP248-2B blocks the binding of 35O22, 3BC315, and PGT151 (but not 8ANC195 or 4E10) to cell surface envelope trimers. Wibmer2017 (antibody interactions)
35O22: This review classified and mapped the binding regions of 32 bNAbs isolated 2010-2016. Wu2016 (review)
35O22: 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)
35O22: 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)
35O22: 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. gp120-gp41 Ab, 35O22 did not bind cell surface whether gp160 was missing C-terminal or not, but did weakly neutralize 92UG037.8 HIV-1 isolate. Chen2015 (neutralization, binding affinity)
35O22: 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). gp120-gp41_ECTO interface glycan bNAb, 35O22, was not able to neutralize or bind B41 pseudovirus and trimer. Pugach2015
35O22: 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
35O22: 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. Among gp120-gp41_ECTO binding bNAbs, 35O22 reciprocally competes 8ANC195, but not PGT151. Surprisingly, 35O22 was competed out in a non-reciprocal manner by anti-V1/V2 glycan NAb, PGT145. Derking2015 (antibody interactions, neutralization, binding affinity, structure)
35O22: 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 have no affinity for the gp120-gp41 interface-binding NAb 35O22 and their pseudo typed viruses were not neutralized by 35O22. Julien2015 (assay or method development, structure)
35O22: 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 bNAb 35O22 to trimers was unaffected by trimer cross-linking. Schiffner2016 (assay or method development, binding affinity, structure)
35O22: 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 11/20 BG505 SOSIP.664-D7324 trimer-immunized rabbits were capable of inhibiting 35O22 binding to gp120-gp41 interface epitopes, but most gp140-immunized and all gp120-immunized sera could not. Sanders2015 (antibody generation, neutralization, binding affinity, polyclonal antibodies)
35O22: Structural analyses mapped the epitopes of 3BC315 and 3BC176 using their Fabs bound to BG505.SOSIP.664. A conserved glycan at N88 was shown to play a role in the binding kinetics of the 2 mAbs. 3BC315 binds between two gp41 subunits and neutralizes the virus by accelerating trimer decay; this modality is unlike other between-subunit mAbs such as 35O22, though all 3 bnAbs do not require MPER to bind. Lee2015 (antibody binding site, structure)
35O22: 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. bNAb 35O22 was able to neutralize 1/16 tested non-M primary isolates at an IC₅₀< 10µg/ml, YBF16,O at 1.44 µg/ml. Morgand2015 (neutralization, subtype comparisons)
35O22: 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. gp41 and interface-binding gl-35O22 did not bind any trimers. Sliepen2015 (binding affinity, antibody lineage)
35O22: 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)
35O22: This is a broad and extremely potent MAb (62% of 181 viruses neutralized with median IC₅₀ 0.033 μg/ml), isolated from the same donor, N152, as for MAb 10E8. 35O22 did not bind monomeric Env, but bound the trimeric BG505 SOSIP.664 at the new site of HIV vulnerability, which includes 4 potential N-linked glycosylation sites N88, N230, N241, N625 as determined by alanine substitution. These sites are in close proximity to the 35O22 heavy chain in the structure reconstructed from images of the 35O22 - BG505 SOSIP.664 complex. N230Q, N624D, and especially N625Q mutations were present in the patient's autologous plasma virus and diminished neutralization when introduced into HIV pseudoviruses, suggesting escape. This MAb derives from IGHV-1-18*02 and IGLV-2-14*02 germline genes, is highly somatically mutated, has CDR H3 composed of 14 amino acids, and an insertion of 8 amino acids in FR3. Huang2014 (antibody binding site, antibody generation, glycosylation, neutralization, escape, structure)

References

Showing 32 of 32 references.

Isolation Paper
Huang2014 Jinghe Huang, Byong H. Kang, Marie Pancera, Jeong Hyun Lee, Tommy Tong, Yu Feng, Ivelin S. Georgiev, Gwo-Yu Chuang, Aliaksandr Druz, Nicole A. Doria-Rose, Leo Laub, Kwinten Sliepen, Marit J. van Gils, Alba Torrents de la Peña, Ronald Derking, Per-Johan Klasse, Stephen A. Migueles, Robert T. Bailer, Munir Alam, Pavel Pugach, Barton F. Haynes, Richard T. Wyatt, Rogier W. Sanders, James M. Binley, Andrew B. Ward, John R. Mascola, Peter D. Kwong, and Mark Connors. Broad and Potent HIV-1 Neutralization by a Human Antibody That Binds the gp41-gp120 Interface. Nature, 3 Sep 2014. PubMed ID: 25186731. Show all entries for this paper.

Barnes2018 Christopher O. Barnes, Harry B. Gristick, Natalia T. Freund, Amelia Escolano, Artem Y. Lyubimov, Harald Hartweger, Anthony P. West, Jr., Aina E. Cohen, Michel C. Nussenzweig, and Pamela J. Bjorkman. Structural Characterization of a Highly-Potent V3-Glycan Broadly Neutralizing Antibody Bound to Natively-Glycosylated HIV-1 Envelope. Nat. Commun., 9(1):1251, 28 Mar 2018. PubMed ID: 29593217. Show all entries for this paper.

Lee2015 Jeong Hyun Lee, Daniel P. Leaman, Arthur S. Kim, Alba Torrents de la Peña, Kwinten Sliepen, Anila Yasmeen, Ronald Derking, Alejandra Ramos, Steven W. de Taeye, Gabriel Ozorowski, Florian Klein, Dennis R. Burton, Michel C. Nussenzweig, Pascal Poignard, John P. Moore, Per Johan Klasse, Rogier W. Sanders, Michael B. Zwick, Ian A. Wilson, and Andrew B. Ward. Antibodies to a Conformational Epitope on gp41 Neutralize HIV-1 by Destabilizing the Env spike. Nat. Commun., 6:8167, 25 Sep 2015. PubMed ID: 26404402. Show all entries for this paper.

Wibmer2017 Constantinos Kurt Wibmer, Jason Gorman, Gabriel Ozorowski, Jinal N. Bhiman, Daniel J. Sheward, Debra H. Elliott, Julie Rouelle, Ashley Smira, M. Gordon Joyce, Nonkululeko Ndabambi, Aliaksandr Druz, Mangai Asokan, Dennis R. Burton, Mark Connors, Salim S. Abdool Karim, John R. Mascola, James E. Robinson, Andrew B. Ward, Carolyn Williamson, Peter D. Kwong, Lynn Morris, and Penny L. Moore. Structure and Recognition of a Novel HIV-1 gp120-gp41 Interface Antibody that Caused MPER Exposure through Viral Escape. PLoS Pathog., 13(1):e1006074, Jan 2017. PubMed ID: 28076415. 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.

Displaying record number 2578

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MAb ID	1B2530
HXB2 Location	Env	Env Epitope Map
Author Location
Epitope
Ab Type	gp120 CD4BS
Neutralizing	P View neutralization details
Contacts and Features	View contacts and features
Species (Isotype)	human(IgG)
Patient	Patient 1
Immunogen	HIV-1 infection
Keywords	antibody binding site, antibody generation, antibody lineage, antibody polyreactivity, antibody sequence, autologous responses, binding affinity, broad neutralizer, computational epitope prediction, elite controllers, escape, glycosylation, neutralization, polyclonal antibodies, review, structure, vaccine antigen design

Notes

Showing 10 of 10 notes.

1B2530: 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. 1B2530 was used for analyzing clade sensitivity and the signature summaries. Bricault2019 (antibody binding site, vaccine antigen design, computational epitope prediction, broad neutralizer)
1B2530: This review classified and mapped the binding regions of 32 bNAbs isolated 2010-2016. Wu2016 (review)
1B2530: 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)
1B2530: This study isolated 4 novel antibodies that bind the CD4 binding site of Env. Population-level analysis classified a diverse group of CD4bs antibodies into two types: CDR H3-dominated or VH-gene-restricted, each with distinct ontogenies. Structural data revealed that neutralization breadth was correlated with angle of approach of the antibodies to the CD4 binding region. 1B2530 was one of the antibodies in the VH gene restricted, 8ANC131-like class. Zhou2015 (neutralization, structure, antibody lineage, broad neutralizer)
1B2530: CD4-binding site Abs are reviewed. New insights from donor-serum responses, atomic-level structures of antibody-Env complexes, and next-generation sequencing of B-cell transcripts are invigorating vaccine-design efforts to elicit effective CD4-binding site Abs. Analysis of the epitopes recognized by CD4-binding Abs reveals substantial similarity in the recognized region of gp120. 1B2530 is a VH1-46-germ-line derived Ab and recognizes gp120 in a manner similar to that of the VRC01-class. Georgiev2013a (review)
1B2530: Neutralizing antibody response was studied in elite controller. Subject VC10042 is an African American male, infected with clade B for 2 decades (since 1984) without any signs of disease and no antiretroviral treatment. The neutralizing activity of autologous CD4bs NAbs was very similar to that of NIH45-46W, but very different from other anti-CD4bs MAbs tested. The viral autologous variants that were resistant to neutralization by autologous and most bnMAbs tested had an extremely rare R272/N368 combination. This mutation was shown in the study to impart a fitness cost to the virus. Sather2012 (autologous responses, elite controllers, neutralization, escape, polyclonal antibodies)
1B2530: 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 CD4-binding site, CD4-mimicry by heavy chain, 8ANC131 class, 1B2530 family. Kwong2012 (review, structure, broad neutralizer)
1B2530: 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. 1B2530 has been referred in discussing the breadth and potency of antiCD4 abs. This ab has CDRL3 of 9-11 residues and will differ from abs with 5 residues CDRL3 in gp120 binding. West2012a (antibody lineage)
1B2530: 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. 1B2530 was used as a control in a competition assay to assess the antibody binding to gp120. Detail information on the binding and neutralization assays are described in the figures S2-S11. Mouquet2012a (glycosylation, neutralization, binding affinity)
1B2530: 576 new HIV antibodies were cloned from 4 unrelated individuals producing expanded clones of potent broadly neutralizing CD4bs antibodies that bind to 2CC core. In order to amplify highly somatically mutated immunoglobulin genes, new primer set with 5' primer set further upstream from the potentially mutated region was used. Despite extensive hypermutation, the new antibodies shared a consensus sequence of 68 IgH chain amino acids and arose independently from two related IgH genes. 1B2530 arises from IgVH1-46 and IgVL1-47 germline genes and neutralized 11/15 isolates from major clades, with IC50<50μg/ml, but none of the 5 VRC01-resistant isolates. 1B2530 is polyreactive - reacted with dsDNA, insulin and LPS, but not with ssDNA. Scheid2011 (antibody generation, neutralization, antibody sequence, antibody polyreactivity, broad neutralizer)

References

Showing 10 of 10 references.

Isolation Paper
Scheid2011 Johannes F. Scheid, Hugo Mouquet, Beatrix Ueberheide, Ron Diskin, Florian Klein, Thiago Y. K. Oliveira, John Pietzsch, David Fenyo, Alexander Abadir, Klara Velinzon, Arlene Hurley, Sunnie Myung, Farid Boulad, Pascal Poignard, Dennis R. Burton, Florencia Pereyra, David D. Ho, Bruce D. Walker, Michael S. Seaman, Pamela J. Bjorkman, Brian T. Chait, and Michel C. Nussenzweig. Sequence and Structural Convergence of Broad and Potent HIV Antibodies That Mimic CD4 Binding. Science, 333(6049):1633-1637, 16 Sep 2011. PubMed ID: 21764753. Show all entries for this paper.

Sather2012 D. Noah Sather, Sara Carbonetti, Jenny Kehayia, Zane Kraft, Iliyana Mikell, Johannes F. Scheid, Florian Klein, and Leonidas Stamatatos. Broadly Neutralizing Antibodies Developed by an HIV-Positive Elite Neutralizer Exact a Replication Fitness Cost on the Contemporaneous Virus. J. Virol., 86(23):12676-12685, Dec 2012. PubMed ID: 22973035. Show all entries for this paper.

Displaying record number 2581

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MAb ID	12A12 (12A12_d57)
HXB2 Location	Env	Env Epitope Map
Author Location
Epitope
Ab Type	gp120 CD4BS
Neutralizing	P View neutralization details
Contacts and Features	View contacts and features
Species (Isotype)	human(IgG)
Patient	Patient 12
Immunogen	HIV-1 infection
Keywords	antibody binding site, antibody generation, antibody lineage, antibody polyreactivity, antibody sequence, assay or method development, autologous responses, binding affinity, broad neutralizer, computational epitope prediction, elite controllers, escape, glycosylation, HIV-2, junction or fusion peptide, neutralization, polyclonal antibodies, review, structure, vaccine antigen design, vaccine-induced immune responses

Notes

Showing 28 of 28 notes.

12A12: 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. 12A12 was used for analyzing clade sensitivity, structural mapping and analyses of CD4bs Ab signatures. Bricault2019 (antibody binding site, vaccine antigen design, computational epitope prediction, broad neutralizer)
12A12: 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)
12A12: This review discusses the identification of super-Abs, where and how such Abs may be best applied and future directions for the field. 12A12 was isolated from human B cell clones and is functionally similar to VRC01. Antigenic region CD4 binding site (Table:1). Walker2018 (antibody binding site, review, broad neutralizer)
12A12: 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)
12A12: Libraries of BG505 gp120 containing mutations were displayed on yeast and screened for binding to a panel of VRC01-class mAbs. Boosted VRC01 gH mice showed broad neutralization on a panel of N276A viruses, neutralization of fully native virus containing the N276 glycan site was limited to a single heterologous tier 2 isolate and was substantially less potent. The progress of vaccine-induced somatic hyper mutation, SHM, toward mature VRC01 was tested. For each VH1-2 sequence, the total number of amino-acid mutations and the number of amino-acid mutations shared with a panel of VRC01-class mAbs like VRC01, PGV04, PGV20, VRC-CH31, 3BNC60, and 12A12 were determined. Extremely deep Ab repertoire sequencing on two healthy HIV-naive individuals were performed to compute the frequency of randomly incorporated VRC01-class mutations in human VH1-2 Ab sequence. Briney2016 (HIV-2, neutralization, vaccine antigen design)
12A12: 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)
12A12: 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)
12A12: This review classified and mapped the binding regions of 32 bNAbs isolated 2010-2016. Wu2016 (review)
12A12: 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)
12A12: 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. Consistent with CD4bs bNAbs, 12A12 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)
12A12: 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-CD4bs bNAb 12A12 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)
12A12: This study presented structures of germline-reverted VRC01-class bNAbs alone and complexed with 426c-based gp120 immunogens. Germline bNAb–426c gp120 complexes showed preservation of VRC01-class signature residues and gp120 contacts, but detectably different binding modes compared to mature bNAb-gp120 complexes. It reported that unlike most antibodies, the overall final structures of VRC01 class antibodies are formed before the antibodies mature. Two versions of germline-binding gp120s were expressed as gp120 cores with N/C termini and V1-V2 and V3 loop truncations. Perhaps to compensate for net LC negative charges post-maturation of the KV1-33–derived VRC01-class bNAb 12A12, the portion of the VL domain encoded by the KV1-33 has a net charge of +6. Scharf2016 (structure)
12A12: 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 12A12 lacked ADCC activity. Bruel2016 (binding affinity)
12A12: The rate of maturation and extent of diversity for the VRC01 lineage were characterized through longitudinal sampling of peripheral B cell transcripts from donor 45 over 15 years and co-crystal structures. VRC01-lineage clades underwent continuous evolution, with rates of ˜2 substitutions per 100 nucleotides per year, comparable with HIV-1 evolution. 39 VRC01-lineage Abs segregated into three major clades, and all Abs from donor 45 contained a cysteine at position 98 (99 in some sequences due to a 1-aa insertion) which was used as a signature to assess membership in the VRC01 lineage. Of 1,041 curated NGS sequences assigned to the VRC01 lineage, six did not contain the cysteine while 1,035 did (99.4%). Structural comparison of 12A12 heavy and light chains and binding surfaces were reported (Table-S5). Wu2015 (structure, antibody lineage)
12A12: 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. 12A12 was not effective in blocking cell to cell transmission of virus. Malbec2013
12A12_d57: TThe ontogeny of VRC01 class Abs was determined by enumerating VRC01-class characteristics in many donors by next-gen sequencing and X-ray crystallography. Analysis included VRC01 (donor NIH 45), VRC-PG04 (donor IAVI 74), VRC-CH31 (donor 0219), 3BNC117 (donor RU3), 12A21 (donor IAVI 57), and somatically related VRC-PG19,19b, 20, 20b MAbs from donor IAVI 23. Despite the sequence differences of VRC01-class Abs, exceeding 50%, Ab-gp120 cocrystal structures showed VRC01-class recognition to be remarkably similar. Zhou2013a (antibody sequence, structure, antibody lineage)
12A12: Next generation sequencing was applied to a new donor C38 (different from donor NIH45) to identify VRC01 class bNAbs. VRC01 class heavy chains were selected through a cross-donor phylogenetic analysis. VRC01 class light chains were identified through a five-amino-acid sequence motif. (CDR L3 length of 5 amino acids and Q or E at position 96 (Kabat numbering) or position 4 within the CDR L3 sequence.) 12A12 was used to compare the heavy & light chain sequences as a template of VRC01 class Ab. Zhu2013a (antibody sequence)
12A12: "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)
12A12: Neutralizing antibody response was studied in elite controller. Subject VC10042 is an African American male, infected with clade B for 2 decades (since 1984) without any signs of disease and no antiretroviral treatment. The neutralizing activity of autologous CD4bs NAbs was very similar to that of NIH45-46W, but very different from other anti-CD4bs MAbs tested. The viral autologous variants that were resistant to neutralization by autologous and most bnMAbs tested had an extremely rare R272/N368 combination. This mutation was shown in the study to impart a fitness cost to the virus. Sather2012 (autologous responses, elite controllers, neutralization, escape, polyclonal antibodies)
12a12: 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)
12A12: 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 CD4-binding site, CD4-mimicry by heavy chain, VRC01 class, 3BNC117 family. Kwong2012 (review, structure, broad neutralizer)
12A12: This review discusses how analysis of infection and vaccine candidate-induced antibodies and their genes may guide vaccine design. This MAb is listed as CD4 binding site bnAb, isolated after 2009 by fluorescence-activated cell sorting (FACS) and 454 deep sequencing. Bonsignori2012b (vaccine antigen design, vaccine-induced immune responses, review)
12A12: 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. 12A12, a CD4bs Ab, was among the 17 bnAbs which were used in studying the mutations in FWR. Klein2013 (neutralization, structure, antibody lineage)
12A12: Computational and crystallographic analysis and in vitro screening were employed to design a gp120 outer domain immunogen (eOD-GT6) that could bind to VRC01-class bNAbs and to their germline precursors. When multimerized on nanoparticles, eOD-GT6 activated germline and mature VRC01-class B cells and thus can be a promising vaccine prime. eOD-GT6 had 10 mutations relative to HXB2. Removal of glycans at positions 276 and 463 was necessary for GL affinity and removal of glycans at positions 386 and 403 also improved affinity. T278R, I371F, N460V are involved in the binding interface. L260F, K357R, G471S stabilize loops involved in the interface. eOD-GT6 bound both 12A12 mature and germline antibodies. Jardine2013 (glycosylation, vaccine antigen design, structure, antibody lineage)
12A12: 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. 12A12 has been referred as a PVL in discussing the breadth and potency of antiCD4 abs. West2012a (antibody lineage)
12A12: 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. 12A12 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)
12A12: 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. 12A12 bound very strongly to the gp120 core and RSC3, strongly bound to gp120 core D368R, weakly bound to RSC3/G367R, very weakly to RSC3 Δ3711 but did not bind to RSC3 Δ3711/P363N. Lynch2012 (binding affinity)
12A12: 576 new HIV antibodies were cloned from 4 unrelated individuals producing expanded clones of potent broadly neutralizing CD4bs antibodies that bind to 2CC core. In order to amplify highly somatically mutated immunoglobulin genes, new primer set with 5' primer set further upstream from the potentially mutated region was used. Despite extensive hypermutation, the new antibodies shared a consensus sequence of 68 IgH chain amino acids and arose independently from two related IgH genes. 12A12 arises from IgVH1-2 and IgVK1D-33 germline genes. It showed binding pattern similar to VRC01’s and neutralized 100% of 118 isolates representing major HIV-1 clades, with IC50<50μg/ml. 12A12 was polyreactive - strongly reacted with dsDNA, LPS, ssDNA and insulin. Scheid2011 (antibody generation, neutralization, antibody sequence, antibody polyreactivity, broad neutralizer)

References

Showing 28 of 28 references.

Briney2016 Bryan Briney, Devin Sok, Joseph G. Jardine, Daniel W. Kulp, Patrick Skog, Sergey Menis, Ronald Jacak, Oleksandr Kalyuzhniy, Natalia de Val, Fabian Sesterhenn, Khoa M. Le, Alejandra Ramos, Meaghan Jones, Karen L. Saye-Francisco, Tanya R. Blane, Skye Spencer, Erik Georgeson, Xiaozhen Hu, Gabriel Ozorowski, Yumiko Adachi, Michael Kubitz, Anita Sarkar, Ian A. Wilson, Andrew B. Ward, David Nemazee, Dennis R. Burton, and William R. Schief. Tailored Immunogens Direct Affinity Maturation toward HIV Neutralizing Antibodies. Cell, 166(6):1459-1470.e11, 8 Sep 2016. PubMed ID: 27610570. Show all entries for this paper.

Bruel2016 Timothée Bruel, Florence Guivel-Benhassine, Sonia Amraoui, Marine Malbec, Léa Richard, Katia Bourdic, Daniel Aaron Donahue, Valérie Lorin, Nicoletta Casartelli, Nicolas Noël, Olivier Lambotte, Hugo Mouquet, and Olivier Schwartz. Elimination of HIV-1-Infected Cells by Broadly Neutralizing Antibodies. Nat. Commun., 7:10844, 3 Mar 2016. PubMed ID: 26936020. Show all entries for this paper.

Jardine2013 Joseph Jardine, Jean-Philippe Julien, Sergey Menis, Takayuki Ota, Oleksandr Kalyuzhniy, Andrew McGuire, Devin Sok, Po-Ssu Huang, Skye MacPherson, Meaghan Jones, Travis Nieusma, John Mathison, David Baker, Andrew B. Ward, Dennis R. Burton, Leonidas Stamatatos, David Nemazee, Ian A. Wilson, and William R. Schief. Rational HIV Immunogen Design to Target Specific Germline B Cell Receptors. Science, 340(6133):711-716, 10 May 2013. PubMed ID: 23539181. 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.

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.

Scharf2016 Louise Scharf, Anthony P. West, Jr., Stuart A. Sievers, Courtney Chen, Siduo Jiang, Han Gao, Matthew D. Gray, Andrew T. McGuire, Johannes F. Scheid, Michel C. Nussenzweig, Leonidas Stamatatos, and Pamela J. Bjorkman. Structural Basis for Germline Antibody Recognition of HIV-1 Immunogens. Elife, 5, 21 Mar 2016. PubMed ID: 26997349. Show all entries for this paper.

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Zhou2013a Tongqing Zhou, Jiang Zhu, Xueling Wu, Stephanie Moquin, Baoshan Zhang, Priyamvada Acharya, Ivelin S. Georgiev, Han R. Altae-Tran, Gwo-Yu Chuang, M. Gordon Joyce, Young Do Kwon, Nancy S. Longo, Mark K. Louder, Timothy Luongo, Krisha McKee, Chaim A. Schramm, Jeff Skinner, Yongping Yang, Zhongjia Yang, Zhenhai Zhang, Anqi Zheng, Mattia Bonsignori, Barton F. Haynes, Johannes F. Scheid, Michel C. Nussenzweig, Melissa Simek, Dennis R. Burton, Wayne C. Koff, NISC Comparative Sequencing Program, James C. Mullikin, Mark Connors, Lawrence Shapiro, Gary J. Nabel, John R. Mascola, and Peter D. Kwong. Multidonor Analysis Reveals Structural Elements, Genetic Determinants, and Maturation Pathway for HIV-1 Neutralization by VRC01-Class Antibodies. Immunity, 39(2):245-258, 22 Aug 2013. PubMed ID: 23911655. Show all entries for this paper.

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Displaying record number 2582

Download this epitope record as JSON.

MAb ID	3BNC60
HXB2 Location	Env	Env Epitope Map
Author Location
Epitope
Ab Type	gp120 CD4BS
Neutralizing	P View neutralization details
Contacts and Features	View contacts and features
Species (Isotype)	human(IgG)
Patient	Patient 3
Immunogen	HIV-1 infection
Keywords	antibody binding site, antibody generation, antibody interactions, antibody lineage, antibody polyreactivity, antibody sequence, assay or method development, binding affinity, broad neutralizer, chimeric antibody, germline, glycosylation, HIV-2, neutralization, review, structure, vaccine antigen design

Notes

Showing 26 of 26 notes.

3BNC60: This review discusses the identification of super-Abs, where and how such Abs may be best applied and future directions for the field. 3BNC60 was isolated from human B cell clones and is functionally similar to VRC01. Antigenic region CD4 binding site (Table:1). Walker2018 (antibody binding site, review, broad neutralizer)
3BNC60: 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)
3BNC60: 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)
3BNC60: Relationship between precursor frequency and antigen binding affinity and how it affects germinal center (GC) B cell recruitment and clonal expansion was examined through adoptive transfer experiments using 3BNC60ˆ{SI} knock-in B cells that carry a synthetic intermediate in the pathway to anti–HIV-1 bNAb development. The data indicated that immunization with soluble HIV-1 antigens can recruit bNAb precursor B cells to the germinal center (GC) when there are as few as 10 such cells per mouse. However, at low precursor frequencies, the extent of clonal expansion was directly proportional to the affinity of the antigen for the B cell receptor, and recruitment to GCs was variable and dependent on recirculation. Dosenovic2018 (antibody lineage)
3BNC60: Libraries of BG505 gp120 containing mutations were displayed on yeast and screened for binding to a panel of VRC01-class mAbs. Boosted VRC01 gH mice showed broad neutralization on a panel of N276A viruses, neutralization of fully native virus containing the N276 glycan site was limited to a single heterologous tier 2 isolate and was substantially less potent. The progress of vaccine-induced somatic hyper mutation, SHM, toward mature VRC01 was tested. For each VH1-2 sequence, the total number of amino-acid mutations and the number of amino-acid mutations shared with a panel of VRC01-class mAbs like VRC01, PGV04, PGV20, VRC-CH31, 3BNC60, and 12A12 were determined. Extremely deep Ab repertoire sequencing on two healthy HIV-naive individuals were performed to compute the frequency of randomly incorporated VRC01-class mutations in human VH1-2 Ab sequence. Briney2016 (HIV-2, neutralization, vaccine antigen design)
3BNC60: This review discusses host controls of bNAb responses and why highly antigenic vaccine Envs do not induce bNAbs when used as vaccine immunogens. VRC01 is not polyreactive against human proteins but has a high avidity for the phylogenetically conserved ubiquitin protein ligase E3A (UBE3A). In Kl mice expressing VRC01 germline with affinity matured HCDR3, bone marrow B cells were not deleted, but immunization of these mice with Envs designed for VRC01 unmutated common ancestor (UCA) induced limited somatic mutations or affinity maturation. In knock-in mice expressing VRC01 non-rearranged VJ germline, there was no B cell deletion in the bone marrow and no anergy in the periphery; vaccination with sequential Envs resulted in affinity maturation to neutralize glycan deleted HIV mutant viruses; maturation was blocked prior to UBE3A crosreactivity. Kelsoe2017 (review, antibody polyreactivity)
3BNC60: 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)
3BNC60: 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-CD4bs 3BNC60 Fab and mouse Fc had improved or reduced in vivo activity depending on the Fc used. Bournazos2014 (neutralization, chimeric antibody)
3BNC60: To track the steps in evolution of bNAbs, VRC01-like anti-CD4bs bNAb 3BNC60 production was studied in human Ig-knock-in mice. Reactive B cell clones were antigen-induced to neutralizing heavy chain production in mature (MuV_H but not germ-line (GLV_H) knock-ins. That initial immunization when followed by immunization with one or a series of related BG505 SOSIP trimers was able to nudge response towards broad neutralization. Dosenovic2015 (neutralization, vaccine antigen design, broad neutralizer)
3BNC60: 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. As with other CD4bs binding bNAbs, 3BNC60 is inhibited by sCD4. It modestly enhanced binding of non-nNAb, 17b. outer domain (OD)-glycan bNAbs, PGT135 and PGT136, though ˜ 5x less efficient binders of trimer, were able to unidirectionally inhibit binding of 3BNC60, as also other CD4bs bNAbs, VRC01, 3BNC117, NIH45-46. Derking2015 (antibody interactions, neutralization, binding affinity, structure)
3BNC60: 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-CD4bs bNAb 3BNC60 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)
3BNC60: VRC01-class bNAb like 3BNC60 protects animals from experimental infection and could contribute to an effective vaccine response. Their predicted germline forms (gl) bind Env inefficiently, which may explain why they are not elicited by HIV-1 Env-immunization. This paper describes modifications that expand the glVRC01-class antibody-recognition potential of the 426c Env. McGuire2016 (antibody interactions, antibody lineage)
3BNC60: 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. CD4bs-binding gl-3BNC60 precursor did not bind to any trimers. Sliepen2015 (binding affinity, antibody lineage)
3BNC60: This study presented structures of germline-reverted VRC01-class bNAbs alone and complexed with 426c-based gp120 immunogens. Germline bNAb–426c gp120 complexes showed preservation of VRC01-class signature residues and gp120 contacts, but detectably different binding modes compared to mature bNAb-gp120 complexes. It reported that unlike most antibodies, the overall final structures of VRC01 class antibodies are formed before the antibodies mature. Two versions of germline-binding gp120s were expressed as gp120 cores with N/C termini and V1-V2 and V3 loop truncations, of which 426c.TM4ΔV1-3 binds to germline versions of 3BNC60. It is reported that 3BNC60GL make all predicted HC VRC01-class signature contacts with the CD4-binding loop, the V5 loop, and loop D to bind to gp120. Scharf2016 (structure)
3BNC60: 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. 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)
3BNC60: 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. 3BNC60 was the most active antibody preventing the cell to cell transmission and was active against cell to cell transmission of T/F viruses. Malbec2013
3BNC60: Envs from clades A, B and C were screened for binding to the germline predecessors of anti-CD4bs bNAbs b12, NIH45-46 and 3BNC60. Mature Abs reacted with diverse Envs, but not the germ-line Abs. Engineered chimeric Abs with mature and germ-line heavy and light chain combinations showed the importance of both mature chains for the cross-reactivity. Hoot2013 (antibody lineage, chimeric antibody)
3BNC60: Next generation sequencing was applied to a new donor C38 (different from donor NIH45) to identify VRC01 class bNAbs. VRC01 class heavy chains were selected through a cross-donor phylogenetic analysis. VRC01 class light chains were identified through a five-amino-acid sequence motif. (CDR L3 length of 5 amino acids and Q or E at position 96 (Kabat numbering) or position 4 within the CDR L3 sequence.) 3BNC60 was used to compare the heavy chain sequence as a template of VRC01 class Ab. Zhu2013a (antibody sequence)
3BNC60: 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 CD4-binding site, CD4-mimicry by heavy chain, VRC01 class, 3BNC117 family. Kwong2012 (review, structure, broad neutralizer)
3BNC60: 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. 3BNC60, a CD4Bs Ab, was among the 17 bnAbs which were used in studying the mutations in FWR. 3BNC60 was used in comparing the Ab framework amino acid replacement vs. interactive surface area on Ab. Crystal structure revealed the importance of a FWR insertion in 3BNC60 increasing its neutralizing potency (described in Fig 5C). Klein2013 (neutralization, structure, antibody lineage)
3BNC60: This study shows that Env immunogens fail to engage the germline-reverted forms of known bnAbs that target CD4BS. However, the elimination of a conserved NLGS at Asn276 in Loop D and the NLGS at positions 460 and 463, located in variable region 5 of Env increased the binding and activation of VRC01 and NIH45-46. 3BNC60 was studied as anti-CD4BS bnAbs belongs to VRC01 class. When germline reverted light chains of 3BNC60 was replced by that of NIH45-46/VRC01, the chimeric Abs recognized the 426c NLGS mutant Envs. McGuire2013 (neutralization, antibody lineage)
3BNC60: 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. 3BNC60 has been discussed as NAb against CD4BS. Kovacs2012 (antibody binding site, neutralization, binding affinity)
3BNC60: Computational and crystallographic analysis and in vitro screening were employed to design a gp120 outer domain immunogen (eOD-GT6) that could bind to VRC01-class bNAbs and to their germline precursors. When multimerized on nanoparticles, eOD-GT6 activated germline and mature VRC01-class B cells and thus can be a promising vaccine prime. eOD-GT6 had 10 mutations relative to HXB2. Removal of glycans at positions 276 and 463 was necessary for GL affinity and removal of glycans at positions 386 and 403 also improved affinity. T278R, I371F, N460V are involved in the binding interface. L260F, K357R, G471S stabilize loops involved in the interface. eOD-GT6 bound both 3BNC60 mature and germline antibodies. Jardine2013 (glycosylation, vaccine antigen design, structure, antibody lineage)
3BNC60: 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. 3BNC60 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)
3BNC60: 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. 3BNC60 bound very strongly to the gp120 core and RSC3, strongly bound to gp120 core D368R, weakly bound to RSC3/G367R but did not bind to RSC3 Δ3711, and RSC3 Δ3711/P363N. Lynch2012 (binding affinity)
3BNC60: 576 new HIV antibodies were cloned from 4 unrelated individuals producing expanded clones of potent broadly neutralizing CD4bs antibodies that bind to 2CC core. In order to amplify highly somatically mutated immunoglobulin genes, new primer set with 5' primer set further upstream from the potentially mutated region was used. Despite extensive hypermutation, the new antibodies shared a consensus sequence of 68 IgH chain amino acids and arose independently from two related IgH genes. 3BNC60 arises from IgVH1-2 and IgVK1D-33 germline genes and neutralized 15/15 isolates with IC50<15μg/ml, and 1/5 VRC01-resistant isolates. 3BNC60 was not polyreactive - reacted with LPS, but not dsDNA, ssDNA and insulin. Solving the crystal structure of the 3BNC60 Fab and comparison with VRC01's revealed conservation of the contacts to the HIV spike. Scheid2011 (antibody generation, neutralization, antibody sequence, structure, antibody polyreactivity, broad neutralizer)

References

Showing 26 of 26 references.

Bournazos2014 Stylianos Bournazos, Florian Klein, John Pietzsch, Michael S. Seaman, Michel C. Nussenzweig, and Jeffrey V. Ravetch. Broadly Neutralizing Anti-HIV-1 Antibodies Require Fc Effector Functions for In Vivo Activity. Cell, 158(6):1243-1253, 11 Sep 2014. PubMed ID: 25215485. Show all entries for this paper.

Dosenovic2015 Pia Dosenovic, Lotta von Boehmer, Amelia Escolano, Joseph Jardine, Natalia T. Freund, Alexander D. Gitlin, Andrew T. McGuire, Daniel W. Kulp, Thiago Oliveira, Louise Scharf, John Pietzsch, Matthew D. Gray, Albert Cupo, Marit J. van Gils, Kai-Hui Yao, Cassie Liu, Anna Gazumyan, Michael S. Seaman, Pamela J. Bjorkman, Rogier W. Sanders, John P. Moore, Leonidas Stamatatos, William R. Schief, and Michel C. Nussenzweig. Immunization for HIV-1 Broadly Neutralizing Antibodies in Human Ig Knockin Mice. Cell, 161(7):1505-1515, 18 Jun 2015. PubMed ID: 26091035. Show all entries for this paper.

Hoot2013 Sam Hoot, Andrew T. McGuire, Kristen W. Cohen, Roland K. Strong, Lars Hangartner, Florian Klein, Ron Diskin, Johannes F. Scheid, D. Noah Sather, Dennis R. Burton, and Leonidas Stamatatos. Recombinant HIV Envelope Proteins Fail to Engage Germline Versions of Anti-CD4bs bNAbs. PLoS Pathog., 9(1):e1003106, Jan 2013. PubMed ID: 23300456. Show all entries for this paper.

Kelsoe2017 Garnett Kelsoe and Barton F. Haynes. Host Controls of HIV Broadly Neutralizing Antibody Development. Immunol. Rev., 275(1):79-88, Jan 2017. PubMed ID: 28133807. Show all entries for this paper.

McGuire2016 Andrew T. McGuire, Matthew D. Gray, Pia Dosenovic, Alexander D. Gitlin, Natalia T. Freund, John Petersen, Colin Correnti, William Johnsen, Robert Kegel, Andrew B. Stuart, Jolene Glenn, Michael S. Seaman, William R. Schief, Roland K. Strong, Michel C. Nussenzweig, and Leonidas Stamatatos. Specifically Modified Env Immunogens Activate B-Cell Precursors of Broadly Neutralizing HIV-1 Antibodies in Transgenic Mice. Nat. Commun., 7:10618, 24 Feb 2016. PubMed ID: 26907590. Show all entries for this paper.

Dosenovic2018 Pia Dosenovic, Ervin E. Kara, Anna-Klara Pettersson, Andrew T. McGuire, Matthew Gray, Harald Hartweger, Eddy S. Thientosapol, Leonidas Stamatatos, and Michel C. Nussenzweig. Anti-HIV-1 B Cell Responses Are Dependent on B Cell Precursor Frequency and Antigen-Binding Affinity. Proc. Natl. Acad. Sci. U.S.A., 115(18):4743-4748, 1 May 2018. PubMed ID: 29666227. Show all entries for this paper.

Andrabi2018 Raiees Andrabi, Jinal N. Bhiman, and Dennis R. Burton. Strategies for a Multi-Stage Neutralizing Antibody-Based HIV Vaccine. Curr. Opin. Immunol., 53:143-151, 15 May 2018. PubMed ID: 29775847. Show all entries for this paper.

Displaying record number 2587

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MAb ID	8ANC131
HXB2 Location	Env	Env Epitope Map
Author Location
Epitope
Ab Type	gp120 CD4BS
Neutralizing	P View neutralization details
Contacts and Features	View contacts and features
Species (Isotype)	human(IgG)
Patient	Patient 8
Immunogen	HIV-1 infection
Keywords	antibody binding site, antibody generation, antibody interactions, antibody lineage, antibody polyreactivity, antibody sequence, binding affinity, broad neutralizer, computational epitope prediction, contact residues, escape, glycosylation, neutralization, review, structure, vaccine antigen design

Notes

Showing 17 of 17 notes.

8ANC131: 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)
8ANC131: 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. 8ANC131 was used for structural mapping and analyses of CD4bs signatures. Bricault2019 (antibody binding site, vaccine antigen design, computational epitope prediction, broad neutralizer)
8ANC131: This review discusses the identification of super-Abs, where and how such Abs may be best applied and future directions for the field. 8ANC131 was isolated from human B cell clones and is functionally similar to VRC01. Antigenic region CD4 binding site (Table:1). Walker2018 (antibody binding site, review, broad neutralizer)
8ANC131: Novel bNAb, IOMA, combines features of VH_1-2/VRC01-class bNAbs with CD4-mimetic CD4bs bNAbs. It is described in complex to BG505 SOSIP.664 Env trimer by 3.5A and 3.9A-resolution crystal structures. The IOMA-BG505 structure demonstrates that VH1-2*02-derived CD4-mimetic bNAbs are not limited to longer, five-residue CDRL3s as in the case of VRC01. This is the first full description of native glycosylated trimer (untrimmed high-mannose and complex-typle N-glycans) revealing Ab-vulnerable glycan holes. Though derived from VRC01, the shorter CDRL3 makes IOMA resemble am 8ANC131-class/VH1-46-derived CD4bs bNAb. The Env binding orientation of IOMA differed from the orientations of VH1-46/8ANC131-class bNAbs. 8ANC131-like bNAbs use their normal-length CDRL3s in place of a W100B HC residue to interact with N279 gp120 /N280 gp120. IOMA is unique in having both an N279 gp120 /N280 gp120-W100F_HC interaction and a normal-length CDRL3, a combination made possible because its CDRL3 is displaced from gp120 loop D and toward the V5 loop. Gristick2016 (glycosylation)
8ANC131: 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. VRC01 was 1 of 4 reference VRC01-like bNAbs - VRC01, 3BNC117, 8ANC131, CH103. Crooks2015 (glycosylation, neutralization)
8ANC131: This review classified and mapped the binding regions of 32 bNAbs isolated 2010-2016. Wu2016 (review)
8ANC131: 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)
8ANC131: This study isolated 4 novel antibodies that bind the CD4 binding site of Env. Population-level analysis classified a diverse group of CD4bs antibodies into two types: CDR H3-dominated or VH-gene-restricted, each with distinct ontogenies. Structural data revealed that neutralization breadth was correlated with angle of approach of the antibodies to the CD4 binding region. 8ANC131 was one of the antibodies in the VH gene restricted, 8ANC131-like class. Zhou2015 (neutralization, structure, antibody lineage, broad neutralizer)
8ANC131: CD4-binding site Abs are reviewed. New insights from donor-serum responses, atomic-level structures of antibody-Env complexes, and next-generation sequencing of B-cell transcripts are invigorating vaccine-design efforts to elicit effective CD4-binding site Abs. Analysis of the epitopes recognized by CD4-binding Abs reveals substantial similarity in the recognized region of gp120. 8ANC131 is a VH1-46-germ-line derived Ab and recognizes gp120 in a manner similar to that of the VRC01-class. Georgiev2013a (review)
8ANC131: 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. 8ANC131 is a CD4bs Ab, with breadth 57%, IC₅₀ 4.02 μg per ml, and its unique feature is CD4 mimicry by its VH1-46-derived heavy chain. Similar MAbs include 8ANC37 and 8ANC134. Kwong2013 (review)
8ANC131: 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, , against 181 diverse HIV-1 strains with available Ab-Ag complex structures. Among the top 10 predicted epitope residues for 8ANC131, only 456, 280, 96, 282 and 461 from region 1 were experimentally validated as part of the actual Ab epitope. Chuang2013 (computational epitope prediction, structure)
8ANC131: "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 VRC01-like cluster. Georgiev2013 (neutralization)
8ANC131: 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 CD4-binding site, CD4-mimicry by heavy chain, 8ANC131 class, 8ANC131 family. Kwong2012 (review, structure, broad neutralizer)
8ANC131: 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. 8ANC131, a CD4bs Ab, was among the 17 bnAbs which were used in studying the mutations in FWR. Klein2013 (neutralization, structure, antibody lineage)
8ANC131: This study shows that Env immunogens fail to engage the germline-reverted forms of known bnAbs that target CD4BS. However, the elimination of a conserved NLGS at Asn276 in Loop D and the NLGS at positions 460 and 463, located in variable region 5 of Env increased the binding and activation of VRC01 and NIH45-46. 8ANC131 was referred to as anti-CD4BS bnAbs. McGuire2013 (neutralization, antibody lineage)
8ANC131: 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. VRC-CH31 has been referred in discussing the breadth and potency of antiCD4 abs. West2012a (antibody lineage)
8ANC131: 576 new HIV antibodies were cloned from 4 unrelated individuals producing expanded clones of potent broadly neutralizing CD4bs antibodies that bind to 2CC core. In order to amplify highly somatically mutated immunoglobulin genes, new primer set with 5' primer set further upstream from the potentially mutated region was used. Despite extensive hypermutation, the new antibodies shared a consensus sequence of 68 IgH chain amino acids and arose independently from two related IgH genes. 8ANC131 arises from IgVH1-46 and IgVK3-11 germline genes and neutralized 7/15 isolates from major clades, with IC50<50μg/ml, but none of the 5 VRC01-resistant isolates. 8ANC131 is polyreactive - reacted with dsDNA, LPS, but not with ssDNA or insulin. Scheid2011 (antibody generation, neutralization, antibody sequence, antibody polyreactivity)

References

Showing 17 of 17 references.

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.

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.

Displaying record number 2588

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MAb ID	8ANC134
HXB2 Location	Env	Env Epitope Map
Author Location
Epitope
Ab Type	gp120 CD4BS
Neutralizing	P View neutralization details
Contacts and Features	View contacts and features
Species (Isotype)	human(IgG)
Patient	Patient 8
Immunogen	HIV-1 infection
Keywords	antibody binding site, antibody generation, antibody lineage, antibody polyreactivity, antibody sequence, binding affinity, broad neutralizer, glycosylation, neutralization, review, structure

Notes

Showing 7 of 7 notes.

8ANC134: This review discusses the identification of super-Abs, where and how such Abs may be best applied and future directions for the field. 8ANC134 was isolated from human B cell clones and is functionally similar to VRC01. Antigenic region CD4 binding site (Table:1). Walker2018 (antibody binding site, review, broad neutralizer)
8ANC134: 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)
8ANC134: This study isolated 4 novel antibodies that bind the CD4 binding site of Env. Population-level analysis classified a diverse group of CD4bs antibodies into two types: CDR H3-dominated or VH-gene-restricted, each with distinct ontogenies. Structural data revealed that neutralization breadth was correlated with angle of approach of the antibodies to the CD4 binding region. 8ANC134 was one of the antibodies in the VH gene restricted, 8ANC131-like class. Zhou2015 (neutralization, structure, antibody lineage, broad neutralizer)
8ANC134: 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 CD4-binding site, CD4-mimicry by heavy chain, 8ANC131 class, 8ANC131 family. Kwong2012 (review, structure, broad neutralizer)
8ANC134: 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. VRC-CH31 has been referred in discussing the breadth and potency of antiCD4 abs. West2012a (antibody lineage)
8ANC134: 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. 8ANC134 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)
8ANC134: 576 new HIV antibodies were cloned from 4 unrelated individuals producing expanded clones of potent broadly neutralizing CD4bs antibodies that bind to 2CC core. In order to amplify highly somatically mutated immunoglobulin genes, new primer set with 5' primer set further upstream from the potentially mutated region was used. Despite extensive hypermutation, the new antibodies shared a consensus sequence of 68 IgH chain amino acids and arose independently from two related IgH genes. 8ANC134 arises from IgVH1-46 and IgVK3-11 germline genes and neutralized 6/15 isolates from major clades, with IC50<50μg/ml, but none of the 5 VRC01-resistant isolates. 8ANC131 is polyreactive - reacted with dsDNA, LPS and ssDNA, but not insulin. Scheid2011 (antibody generation, neutralization, antibody sequence, antibody polyreactivity)

References

Showing 7 of 7 references.

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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Displaying record number 2583

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MAb ID	8ANC195
HXB2 Location	Env	Env Epitope Map
Author Location	Env
Epitope
Ab Type	gp41-gp120 interface
Neutralizing	P View neutralization details
Contacts and Features	View contacts and features
Species (Isotype)	human(IgG)
Patient	Patient 8
Immunogen	HIV-1 infection
Keywords	ADCC, antibody binding site, antibody generation, antibody interactions, antibody lineage, antibody polyreactivity, antibody sequence, assay or method development, binding affinity, broad neutralizer, computational epitope prediction, contact residues, elite controllers, escape, glycosylation, immunotherapy, neutralization, review, structure, subtype comparisons, vaccine antigen design, vaccine-induced immune responses

Notes

Showing 34 of 34 notes.

8ANC195: 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. 8ANC195-Env formed a distinct group within the Subunit Interface category, Class 8ANC195, interacting with glycan N276 of Env (as do other Abs, but of CD4bs category!). Crystal structure data for 8ANC195 complexed to BG505 SOSIP.664 trimer was found in PDB ID: 5CJX. Chuang2019 (antibody binding site, antibody interactions, neutralization, binding affinity, antibody sequence, structure, antibody lineage, broad neutralizer)
8ANC195: 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)
8ANC195: This review discusses how the identification of super-antibodies, where and how such antibodies may be best applied and future directions for the field. 8ANC195, a prototype super-Ab, was isolated from human B cell clones. Antigenic region gp120–gp41 interface (Table:1). Walker2018 (antibody binding site, review, broad neutralizer)
8ANC195: 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)
8ANC195: 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)
8ANC195: 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. 8ANC195 recognizes this trimer antigenically. Chuang2017 (antibody interactions)
8ANC195: 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)
8ANC195: 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)
8ANC195: A weakly neutralizing antibody was isolated, CAP248-2B. The glycan dependence of CAP248-2B was compared to other known gp120-gp41 interface targeting bNAbs (8ANC195, 35O22, PGT151, 3BC315). CAP248-2B blocks the binding of 35O22, 3BC315, and PGT151 (but not 8ANC195 or 4E10) to cell surface envelope trimers. Wibmer2017 (antibody interactions)
8ANC195: 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. PGT151 and 8ANC195 were used as Abs that recognize the gp120-gp41 interface; they did not mediate strong ADCC activity. Ding2015 (ADCC)
8ANC195: 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. 8ANC195 was used as a reference Ab. Crooks2015 (glycosylation, neutralization)
8ANC195: This review classified and mapped the binding regions of 32 bNAbs isolated 2010-2016. Wu2016 (review)
8ANC195: 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)
8ANC195: 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)
8ANC195: 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. Ab anti-gp120-gp41 8ANC195 bound cell surface whether gp160 was missing C-terminal or not, and neutralized 92UG037.8 HIV-1 isolate, both weakly. Chen2015 (neutralization, binding affinity)
8ANC195: 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). gp120-gp41_ECTO interface glycan bNAb, 8ANC195, neutralized B41 psuedovirus. Pugach2015
8ANC195: 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. Within gp120-gp41_ECTO bNAbs, 8ANC195 strongly cross-competes and reciprocally with PGT151 and 35O22. It was surprisingly also inhibited by apex-binding PGT145. Reciprocally enhanced binding was seen between 8ANC195 and V3-glycan PGT126. 8ANC195 also enhances N-276 dependent, CD4bs-bNAb 3BNC117's binding. Derking2015 (antibody interactions, neutralization, binding affinity, structure)
8ANC195: 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 have low affinity for the gp120-gp41 interface-binding NAb 8ANC195 and their pseudo typed viruses were not neutralized by 8ANC195. Julien2015 (assay or method development, structure)
8ANC195: 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 contrast no significant difference in neutralization sensitivity was seen between HIV-1 and bNAb 8ANC195. vandenKerkhof2016 (elite controllers, neutralization, escape)
8ANC195: 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-CD4bs bNAb 8ANC195 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)
8ANC195: 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. bNAb 8ANC195 was able to neutralize 1/16 tested non-M primary isolates at an IC₅₀< 1 µg/ml, RBF208,M/O at 0.31 µg/ml. Morgand2015 (neutralization, subtype comparisons)
8ANC195: The dynamics and characteristics of anti-antibody responses were described for monkeys that received adenovirus-mediated delivery of either rhesus anti-SIV antibody constructs (4L6 or 5L7) in prevention trials, or a combination of rhesusized human anti-HIV antibodies (1NC9/8ANC195/3BNC117 or 10-1074/10E8/3BNC117) in therapy trials. Anti-antibody responses to the human mAbs were correlated to the distance from the germline Ab sequences. Martinez-Navio2016 (immunotherapy)
8ANC195: The crystal structure of the BG505 SOSIP Env trimer in complex with PGT128 and 8ANC195 revealed the antibody epitopes and sites of Env vulnerability. PGT128 was shown to bind N137, N156, N301,and N332, with an indirect interaction with N262. 8ANC195 was shown to bind to N234, N276, and N637. Kong2015a (structure)
8ANC195: 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 8ANC195 lacked ADCC activity. Bruel2016 (ADCC, binding affinity)
8ANC195: This structural and biochemical study defined the gp120-gp41 binding site of 8ANC195 which is near the CD4bs. While CD4 binding tends to open the trimer structure, binding of 8ANC195 reverses this open Env trimer conformation, preventing gp41-mediated fusion of host and viral membranes. Crystal structures of a more potent variant, 8ANC195_G52K5 demonstrate simultaneous binding of both sCD4 and 8ANC195 to gp120-gp41. Thus 8ANC195 is a bnAb that can recognize both closed and open states of the Env trimer, and it can accommodate conformational change in order to neutralize infection. Scharf2015 (antibody binding site, structure)
8ANC195: Structures of the 8ANC195 Fab were determined, both alone and in complex with HIV. 8ANC195 inserts a heavy-chain variable domain into a gap in the Env glycan shield. The 8ANC195 epitope involves gp120 glycans and protein residues of the gp120 inner domain, and it bridges the gp120 and gp41 subunits of HIV-1 Env. Scharf2014 (antibody binding site, structure)
8ANC195: 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 cell to cell 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. 8ANC195 was not effective in preventing cell to cell transmission of virus. Malbec2013
8ANC195: 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, , against 181 diverse HIV-1 strains with available Ab-Ag complex structures. This method was prospectively applied to the prediction of epitope residues for 8ANC195 and was also experimentally validated. In agreement with the computational prediction, three of the top 10 residues 234, 236 and 276 play major role in 8ANC195 binding. This suggests that 8ANC195 is a glycan-reactive Ab targeting a novel epitope on gp120. Chuang2013 (glycosylation, computational epitope prediction, structure)
8ANC195: "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 VRC01-like cluster. Georgiev2013 (neutralization)
8ANC195: 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)
8ANC195: This review discusses how analysis of infection and vaccine candidate-induced antibodies and their genes may guide vaccine design. This MAb is listed as CD4 binding site bnAb, isolated after 2009 by fluorescence-activated cell sorting (FACS) and 454 deep sequencing. Bonsignori2012b (vaccine antigen design, vaccine-induced immune responses, review)
8ANC195: 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. 8ANC195 was among the 17 bnAbs which were used in studying the mutations in FWR. Klein2013 (neutralization, structure, antibody lineage)
8ANC195: 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. 8ANC195 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)
8ANC195: 576 new HIV antibodies were cloned from 4 unrelated individuals producing expanded clones of potent broadly neutralizing CD4bs antibodies that bind to 2CC core. In order to amplify highly somatically mutated immunoglobulin genes, new primer set with 5' primer set further upstream from the potentially mutated region was used. Despite extensive hypermutation, the new antibodies shared a consensus sequence of 68 IgH chain amino acids and arose independently from two related IgH genes. 8ANC195 did not entirely conform to the consensus and did not arise from related heavy or light chains. 8ANC195 arises from IgVH1-69 and IgVK1-5 germline genes and neutralized 57% of 118 isolates representing major HIV-1 clades, with IC50<50μg/ml. All of the antibodies tested, except 8ANC195, resemble CD4 and VRC01 in that they facilitate CD4i-antibody binding to one or both viral spikes. 8ANC195, was not a traditional CD4bs antibody in that it was equally sensitive to the D368R and I420R mutations and it differed from the others in its neutralization pattern. 8ANC195 was polyreactive - strongly reacted with dsDNA and LPS, ssDNA and insulin. Scheid2011 (antibody generation, neutralization, antibody sequence, antibody polyreactivity, broad neutralizer)

References

Showing 34 of 34 references.

Ding2015 Shilei Ding, Maxime Veillette, Mathieu Coutu, Jérémie Prévost, Louise Scharf, Pamela J. Bjorkman, Guido Ferrari, James E. Robinson, Christina Stürzel, Beatrice H. Hahn, Daniel Sauter, Frank Kirchhoff, George K. Lewis, Marzena Pazgier, and Andrés Finzi. A Highly Conserved Residue of the HIV-1 gp120 Inner Domain Is Important for Antibody-Dependent Cellular Cytotoxicity Responses Mediated by Anti-cluster A Antibodies. J. Virol., 90(4):2127-2134, Feb 2016. PubMed ID: 26637462. Show all entries for this paper.

Kong2015a Leopold Kong, Alba Torrents de la Peña, Marc C. Deller, Fernando Garces, Kwinten Sliepen, Yuanzi Hua, Robyn L. Stanfield, Rogier W. Sanders, and Ian A. Wilson. Complete Epitopes for Vaccine Design Derived from a Crystal Structure of the Broadly Neutralizing Antibodies PGT128 and 8ANC195 in Complex with an HIV-1 Env trimer. Acta Crystallogr. D Biol. Crystallogr., 71(Pt 10):2099-2108, Oct 2015. PubMed ID: 26457433. Show all entries for this paper.

Martinez-Navio2016 José M. Martinez-Navio, Sebastian P. Fuchs, Sònia Pedreño-López, Eva G. Rakasz, Guangping Gao, and Ronald C. Desrosiers. Host Anti-Antibody Responses Following Adeno-Associated Virus-Mediated Delivery of Antibodies Against HIV and SIV in Rhesus Monkeys. Mol. Ther., 24(1):76-86, Feb 2016. PubMed ID: 26444083. Show all entries for this paper.

Scharf2014 Louise Scharf, Johannes F. Scheid, Jeong Hyun Lee, Anthony P. West, Jr., Courtney Chen, Han Gao, Priyanthi N. P. Gnanapragasam, René Mares, Michael S. Seaman, Andrew B. Ward, Michel C. Nussenzweig, and Pamela J. Bjorkman. Antibody 8ANC195 Reveals a Site of Broad Vulnerability on the HIV-1 Envelope Spike. Cell Rep., 7(3):785-795, 8 May 2014. PubMed ID: 24767986. Show all entries for this paper.

Scharf2015 Louise Scharf, Haoqing Wang, Han Gao, Songye Chen, Alasdair W. McDowall, and Pamela J. Bjorkman. Broadly Neutralizing Antibody 8ANC195 Recognizes Closed and Open States of HIV-1 Env. Cell, 162(6):1379-1390, 10 Sep 2015. PubMed ID: 26359989. Show all entries for this paper.

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MAb ID	b12 (Fab b12, MAb IgG1b12, IgG1-b12, IgG1 b12, IgGB12, b4/12, Ib12, 1b12)
HXB2 Location	Env	Env Epitope Map
Author Location	gp120
Research Contact	D. Burton, Scripps Research Institute, La Jolla, CA, also J. Geltowsky and J. Pyati, R. W. Johnson Pharmaceutical Resear
Epitope	(Discontinuous epitope)
Subtype	B
Ab Type	gp120 CD4BS
Neutralizing	L P (tier 2) View neutralization details
Contacts and Features	View contacts and features
Species (Isotype)	human(IgG1κ)
Patient	Donor b
Immunogen	HIV-1 infection
Keywords	acute/early infection, ADCC, adjuvant comparison, 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, chimeric antibody, co-receptor, complement, computational epitope prediction, dendritic cells, drug resistance, dynamics, elite controllers, enhancing activity, escape, genital and mucosal immunity, germline, 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 575 of 575 notes.

b12: 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. b12-Env formed a distinct group within the CD4bs category, Class b12. Data for Fab variable domain of phage-library-derived Ab b12 as a cryo-EM model complexed to B41 SOSIP.664 was found in PDB ID: 5VN8. Chuang2019 (antibody binding site, antibody interactions, neutralization, binding affinity, antibody sequence, structure, antibody lineage, broad neutralizer)
b12: 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)
b12: 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)
b12: 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)
b12: 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)
b12: 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 CD4-binding site (CD4bs) recognized by VRC01 and b12, 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)
b12: Isolation of human mAb, E10, from an HIV-1-infected patient sample by single B cell sorting and single cell PCR has been reported. E10 showed binding to gp140 trimer and linear peptides derived from gp41 membrane proximal external region (MPER). E10 epitope (QEKNEQELLEL) overlapped with mAb 2F5 epitope. E10 showed low neutralization activity and narrow spectrum of neutralization compared to b12, but it mediated higher ADCC activity than b12 at low antibody concentration. Fine mapping of E10 epitope may potentiate MPER-based subunit vaccine development. Yang2018 (ADCC, antibody binding site)
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). All of the isolates from subject VC20013 were very susceptible to bNAbs that target the CD4 binding site (CD4-BS), including b12 and VRC01. Sather2014 (neutralization, broad neutralizer)
b12: 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. b12 was included in the study to analyze phylogenetically corrected signatures of CD4bs bNAb. Bricault2019 (antibody binding site, neutralization, vaccine antigen design, computational epitope prediction, broad neutralizer)
b12: A novel antibody, Y498, was derived from donor XJ1981, whose serum had potent and broad neutralization activity. Y498 neutralized 30% of 70 tested HIV-1 isolates and targeted an epitope overlapping the CD4bs of gp120. The neutralization of Y498 was compared to that of 3 other CD4BS antibodies: VRC01, b12, and A16. Sun2017 (antibody generation, neutralization, broad neutralizer)
Ig1b12: Improvements to the standardization of the HIV-1 pseudovirus production procedure by implementing an automated system for aliquoting of HIV-1 pseudovirus stocks up to liter-scale are described. The automated platform and the aliquoting process were validated on as accuracy, precision, specificity and robustness. Lot-to-lot variations and virus stock integrity were assessed through two parallel neutralization assays run with the automatically aliquoted HIV pseudovirus and a manually aliquoted reference virus of the same type, by using five control reagents: sCD4, b12, 2F5, 4E10 and TriMab consisting of 2G12, IgG1b12 and 2F5. Schultz2018 (assay or method development, neutralization)
b12: 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)
b12: 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)
b12: 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)
b12: 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 b12 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)
b12: 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 b12 in ELISA EC50 and Surface Plasmon Resonance (SPR) assays. 6240.B gp120 exhibited binding to b12. Wen2018 (glycosylation, vaccine antigen design)
b12: 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)
b12: 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. Envs with or without the TM1 mutations were expressed in HEK 293T cells and analyzed for the relative expression of Ab epitopes including the CD4 binding site for b12. Hogan2018 (vaccine antigen design)
B12: In the RV305 HIV-1 vaccine trial, two boosts of either ALVAC-HIV, AIDSVAX B/E gp120 or ALVAC-HIV + AIDSVAX B/E gp120 were given to HIV-1-uninfected RV144 vaccine-recipients. While no bNAb plasma activity was induced in this trial as well, an increased frequency of memory B cells that produce Env-specific anti-CD4bs antibodies with long HCDR3s was detected. B12 binding to the D368R CD4bs-mutant of Env protein YU2 was reduced to 2% as compared to wt. Easterhoff2017 (binding affinity)
IgG1b12: 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. b12 recognizes this trimer antigenically. Chuang2017 (antibody interactions)
IgG1b12: 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)
IgG1b12: Env variants that lack all 15 core glycan sites were produced. These variants retain conformational integrity and viral infectivity and bind to several bNAbs, including VRC01 and b12, suggesting that Env glycans are not essential to protein folding, and deglycosylated antigens may be useful as priming immunogens. A partially germline-reverted variant of VRC01 (GL-VRC01) was produced to compare its binding to that of VRC01. Rathore2017 (glycosylation, vaccine antigen design)
IgG1b12: 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)
IgG1b12: 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. Anti-gp120 b12 was used to prove that the VLP spike included the broad neutralization epitope recognized by it. Huang2017a (therapeutic vaccine, variant cross-reactivity)
IgG1b12: The light and heavy chains of human bNAb b12 were spliced into the rhesus macaque kappa light chain and the macaque IgG1 or IgA heavy chain to produce RhB12 IgG and RhB12 IgA. Administration of these antibodies into lactating rhesus macaques resulted in high plasma concentrations of the antibody and varied concentrations in mucosal compartments. RhB12 IgG was higher than RhB12 IgA in saliva, rectal, and vaginal secretions, but the concentration of RhB12 IgA was much higher in breast milk. This very high concentration in milk suggests that passive immunization may be effective in inhibiting virus in breast milk. Fouda2016 (immunoprophylaxis, immunotherapy)
IGg1b12: 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)
b12: 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. IgG1b12 also gave strong protection in mice. Pegu2017 (immunoprophylaxis, review)
IgG1b12: 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. VRC01 and b12 were selected as Abs that recognize the CD4 binding site. Ding2015 (ADCC)
IgG1b12: 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. VRC01, b12, and CH31 were selected as representative mAbs of the CD4-BS class. Cheeseman2017 (genital and mucosal immunity, immunoprophylaxis)
b12: 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)
IgG1b12: Protection by mAbs was tested in two models of mucosal HIV-1 transmission. Broadly neutralizing Abs (CH31, b12), but not non-neutralizing Abs (CH29, CH38, CH54, CH57, CH90, CH58, HG129, HG130, 7b2, CH65) were able to block HIV infection in human vaginal explants. Infusion of CH31, but not CH54 or CH38, protected rhesus macaques against SHIV challenge. Astronomo2016 (immunoprophylaxis)
IgG1b12: 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. All the neutralizing rabbit sera showed significant competition with CD4bs mAbs VRC03,VRC07, b12 and 1F7. b12 binds native SOS E168K trimer and is residue D368-dependent for trimer binding. Introduction of the N197 glycan into JR-FL trimer leads to a ˜4 fold reduction in b12 IC₅₀. Crooks2015 (glycosylation, neutralization)
IgG1b12: 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)
IgG1b12: 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)
IgG1b12: 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)
IgG1b12: 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)
b12: 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)
IgG1b12: 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). CD4bs bNAb, b12, was able to neutralize and bind B41 pseudovirus and trimer. Pugach2015
IgG1b12: 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 2.5 fold resistance against anti-CD4bs bNAb, b12, along with mutation at contact residue 475. vandenKerkhof2016 (elite controllers, neutralization, escape)
IgG1b12: 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-CD4bs non-NAb b12 did not neutralize BG505.T332N, the pseudoviral equivalent of the immunogen BG505 SOSIP.664 gp140, and did not recognize or bind the immunogen either. Sanders2013 (assay or method development, neutralization, binding affinity)
b12: This review discusses an array of methods to engineer more effective bNAbs for immunotherapy. Antibody b12 is an example of engineering through directed evolution; its affinity and breadth can be greatly increased. Hua2016 (immunotherapy, review)
IgG1b12: 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 b12 was assayed against JRFL-M373RP370L (resistant strain) and JRFL (sensitive strain). Magnus2016 (neutralization, escape)
IgG1b12: 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). Anti-CD4bs nAb, b12, does not neutralize BG505.T332N pseudovirus; binds neglibly to the trimer, but well to the protomer and monomer immunogens. Yasmeen2014 (antibody binding site, assay or method development)
b12: 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. CD4 bs-binding, first generation mAb, b12 when compared had a geometric mean of IC₅₀=2.4 µg/ml for the 1/12 viruses it neutralized at a potency of 8%. 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)
b12: Donor EB179 was a long-term non-progressor with high serum neutralization breadth and potency. 8 B-cell clones produced antibodies of which 179NC75 had the highest neutralization, especially to Clade B virus, neutralizing 70% of a clade-B pseudovirus panel and 6 out of 9 cross-clade Env pseudoviruses. When compared to other CD4bs bNAbs against a panel of 22 Tier-2 clade B viruses, 179NC75 was more potent than b12 against 13 viruses. Freund2015 (neutralization, broad neutralizer)
b12: 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 b12 has been associated with viral suppression in studies in humans and macaques. Halper-Stromberg2016 (immunotherapy, review)
IgG1b12: Pre-binding of 4E10 at the MPER affects the binding of b12 at the CD4 binding site. Finton2014 (antibody interactions)
IgG1b12: 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. b12 neutralized 29% of the 199 viruses tested, whereas a previous study had estimated this value at 50%. Hraber2014 (neutralization)
b12: 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 b12 the published IMGT predicted allele was IGHV3-21*01 and alternate allele predicted from IGHV alleles in 28 South African individuals was IGHV3-21*1m, with G291A synonymous nucleotide change. Scheepers2015 (antibody lineage)
b12: CD4-binding site Abs are reviewed. New insights from donor-serum responses, atomic-level structures of antibody-Env complexes, and next-generation sequencing of B-cell transcripts are invigorating vaccine-design efforts to elicit effective CD4-binding site Abs. Analysis of the epitopes recognized by CD4-binding Abs reveals substantial similarity in the recognized region of gp120. b12 is able to bind to functional viral spikes, inducing only small conformational changes and also binds to a region on the outer domain that is outside of the site of CD4-binding. Georgiev2013a (review)
b12: 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 VK with identical VJ recombination to b12 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)
IgG1b12: 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)
IgG1b12: 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. Two CD4bs-targeting Abs, b12 and PGV04, had high potential neutralization values, perhaps reflecting relative insensitivity to Env glycan expression. McCoy2015 (neutralization)
b12: Autoreactivity and polyspecificity of b12 using a synthetic human peptidome has been reported and compared with 4E10. b12 was shown to be polyreactive, binding peptides from various proteins, but only in a limited manner and b12 was analyzed to provide a baseline for results. Finton2013 (structure, antibody polyreactivity)
b12: N276D was determined as the critical binding site of MAb HJ16 by resistance induction in a sensitive primary CRF02_AG strain. Removing the N-linked glycosylation site via the N276D mutation greatly increased resistance to HJ16. The N276D mutation increased the sensitivity of 3 viral strains to VRC01 and VRC03, but not to mAb b12 or to two llama single heavy chain antibodies, A12 and 1B5. Balla-Jhagjhoorsingh2013 (glycosylation, neutralization)
b12: Novel llama VHH antibodies were derived by immunization of llamas with HIV-1 Env. The binding and neutralization potency of these new anti-CD4bs antibodies were compared with previously-characterized llama antibodies A12, D7, and C8, and human antibody b12. mAb b12 nuetralized 14/26 predominantly tier 2 viruses tested. Strokappe2012 (neutralization, binding affinity)
IgG1b12: This paper showed that FcγRI occasionally potentiates neutralization by Abs against the V3 loop of gp120 and cluster I of gp41. FcγRI providing a kinetic advantage for neutralizing Abs against partially cryptic epitopes independent of phagocytosis has been reported. The antibiotic bafilomycin A1 and the weak base chloroquine were used as lysosomotropic agents to block phagocytosis in TZM-bl and TZM-bl/FcγRI cells. These treated cells and 2 HIV-1 subtype B Env-pseudotyped viruses (6535.3 and QH0692.42) were assayed with IgG1b12. FcγRI had no effect on the neutralizing activity of IgG1b12, and the activity of this MAb was unaltered by the lysosomotropic agents. Perez2013 (antibody interactions)
b12: 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 >400-fold for b12-aplaviroc against the YU2 isolate. Gavrilyuk2013 (neutralization)
b12: 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. AAV8 vector was used and b12 (over 100 μg/mL) was the only antibody that afforded full protection. Yang2014 (immunoprophylaxis, review, antibody gene transfer)
B12: 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)
IgG1b12: 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)
IgG1b12: 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 for comparison. Upadhyay2014 (glycosylation, neutralization)
b12: 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)
1b12: 1b12 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 CD4BS binding Nab bound well at <10 nM to 2/5 chronic Envs, 3/6 Consensus Envs and 6/7 T/F Envs. Liao2013c (antibody interactions, binding affinity)
b12: 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. b12 neutralized both VC10042.08 and VC10042.ela, but bound to only VC10042.ela. Carbonetti2014 (elite controllers, vaccine-induced immune responses)
b12: 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. b12 Fc mutant I253A abrogated FcRn binding and lowered the transcytosis whereas mutant M428L increased the FcRn binding as well as transcytosis compared to WT. Both infectious and noninfectious viruses were transcytosed by b12. Gupta2013
b12: 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 (BCR) forms of known bNAbs. Envs tested showed various degrees of affinities to mutated b12 sIgG and BCR but not to predicted germ line b12BCR. Ca²⁺ influx through the b12BCR was also tested as a function of binding affinity. Removal of selected N-linked glycosylaion sites on Env did not confer binding to the predicted germline b12. McGuire2014 (antibody interactions, antibody lineage)
b12: 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. Neutralization by b12, which targets CD4bs of gp41, was not affected by V1 mutation as shown against T138N and ΔN. Drummer2013 (antibody interactions, glycosylation)
b12: 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. b12 bound to BG505L111A monomer, but failed to neutralize BG505 pseudovirus. Hoffenberg2013 (antibody interactions)
b12: 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 neutralization breadth across clades. b12 neutralized 35% of a cross-clade panel of 157 HIV-1 isolates (Fig. S1) while 1F7 neutralized only 20% of the isolates. Gach2013 (neutralization)
b12: Envs from clades A, B and C were screened for binding to the germline predecessors of anti-CD4bs bNAbs b12, NIH45-46 and 3BNC60. Mature Abs reacted with diverse Envs, but not the germ-line Abs. Engineered chimeric Abs with mature and germ-line heavy and light chain combinations showed the importance of both mature chains for the cross-reactivity. Hoot2013 (antibody lineage, chimeric antibody)
b12: 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. b12 was used as a reference Ab in neutralization assay comparing A3R5 and TZM-bl. McLinden2013 (assay or method development)
b12: 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. b12 is a CD4bs Ab, with breadth 33%, IC₅₀ 2.7 μg per ml, and its unique feature is being derived from a phage display. Kwong2013 (review)
b12: 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. b12 was used in CD4 coexpression and competitive binding assay. Veillette2014 (ADCC)
b12: 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 b12 and PGT121 to evaluate neutralization activity of the intermediate divergence. 3H+3L showed 3fold more potency and 32H+3L showed 15 fold more potency than b12. Sok2013
b12: 2 HIV-1 infectious molecular clones (IMCs) derived from subtypes C and CRF01_AE HIV-1 primary isolates expressing LucR (IMC.LucR) were engineered to express heterologous gp160 Envs. The IMCs were generally resistant to neutralization by b12. Chenine2013 (assay or method development, neutralization)
b12: 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)
IgG1b12: 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)
b12: 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. Barouch2013a (immunotherapy)
b12: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 epitope overlaps most extensively with the CD4 binding site of b12. Acharya2013 (neutralization)
IGgb12: 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)
b12: 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 b12, against 181 diverse HIV-1 strains with available Ab-Ag complex structures. Chuang2013 (computational epitope prediction)
b12: 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. Both b12 and b12 LALA mutant, which can't bind with the Fc receptor were used in the screening process. b12 LALA didn't exhibit any ADCC activity confirming the Fc gammaR dependency of ADCC assay. Moog2014 (ADCC, SIV)
b12: The complexity of the epitopes recognized by ADCC responses in HIV-1 infected individuals and candidate vaccine recipients is discussed in this review. b12 is discussed as the CD4bs-targeting, neutralizing anti-gp120 mAb exhibiting ADCC activity and having a discontinuous epitope. b12 LALA variant and other non-fucosilated variants showed less in vivo protection despite higher ADCC. Both VRC01 and b12 recognize the outer domain of gp120. b12 recognizes by using its Ab heavy chain, where as VRC01 uses both heavy and light chains. This difference is crucial for differences in their neutralization breadth. Pollara2013 (ADCC, review)
b12: "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)
b12: 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". b12 was used in the anti-gp120 cocktail in BN-PAGE and western blot experiments to prove that enzymes removed junk Env from VLPs and inactivated virus. Crooks2011 (glycosylation)
b12: 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. b12 was used as a positive control in the assays. Guan2013 (ADCC, antibody interactions)
b12: Cryoelectron tomography was used to determine structures of A12, m36, or m36/CD4 complexed to trimeric Env displayed on intact HIV-1 BaL virus. Binding of Env with HIV neutralizing protein A12 results in a "partially open" conformation change very similar to binding with CD4 binding site-Ab b12. The steric interactions at the distal ends of the bound Ab moieties are likely to play a role in determining the rotation of gp120 as in A12 and b12 or without any quaternary structure change as in VRC01. Meyerson2013 (antibody binding site, structure)
b12: Systematic computational analyses of gp120 plasticity and conformational transition in complexes with CD4 binding fragments, mimetic proteins and Ab fragments is described to explain the molecular mechanisms by which gp120 interacts with the CD4bs at local and subdomain levels. An isotopic elastic network analysis, a full atomic normal mode analysis and simulation of conformational transitions were used to compare the gp120 structures in CD4 bound and b12 Ab-bound states. Korkut2012 (structure)
b12: The role of NK cells and NK cell receptor polymorphisms in the assessment of HIV-1 neutralization is reported. b12 was used in viral inhibition assay as a control to compare NK cells participation and activity. Brown2012 (neutralization, NK cells)
b12: 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. b12 was used in ELISA to asses the recognition of the purified Env glycoproteins and recognized conformation dependent epitopes near CD4 binding site of gp120. Mao2012 (structure)
b12: 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. b12 was used as a anti-CD4 binding site Ab to study effects of Ab specificity and affinity on ADCC against HIV-1 infected targets. Smalls-Mantey2012 (ADCC, assay or method development)
IgG1b12: Neutralizing antibody response was studied in elite controller. Subject VC10042 is an African American male, infected with clade B for 2 decades (since 1984) without any signs of disease and no antiretroviral treatment. The neutralizing activity of autologous CD4bs NAbs was very similar to that of NIH45-46W, but very different from other anti-CD4bs MAbs tested. The viral autologous variants that were resistant to neutralization by autologous and most bnMAbs tested had an extremely rare R272/N368 combination. This mutation was shown in the study to impart a fitness cost to the virus. Sather2012 (autologous responses, elite controllers, neutralization, escape, polyclonal antibodies)
b12: 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. b12 was used as a CD4bs MAb to compare neutralizing specificity of VRC06. Li2012
b12: 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. Differences in sensitivity to b12 were not completely explained by mutations in its contact residues, but b12 sensitivity correlated with numerous context dependent residues outside the epitope. Wang2012 (mother-to-infant transmission)
b12: 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)
b12: A novel system for genetically manipulating B cells for B-cell based gene therapy is presented and called a “Molecular Rheostat”. The system is based on the use of mutated “self-cleaving” 2A peptides. Lentiviral transgenesis of Molecular Rheostat constructs into B cell lines enables the simultaneous expression of functional b12-based IgM-like BCRs that signal to the cells and mediate the secretion of b12 IgG broadly neutralizing antibodies that can bind and neutralize HIV-1 pseudovirus. These b12-based Molecular Rheostat constructs promote the maturation of EU12 B cells in an in vitro model of B lymphopoiesis. Yu2012 (assay or method development)
b12: Milk-derived b12 IgA2 was compared with CHO-derived b12 IgA2 (or IgG1) in transgenic mice. Immunoreactivity was retained. When tested for neutralization, milk-derived b12 IgA2 was at least comparable to CHO-derived antibody and in some cases, superior to CHO-derived antibody. Furthermore, milk that expressed b12 IgA2 was significantly more effective at mediating antibody-dependent cell killing, suggesting that it is possible to achieve functional HIV-specific mAb in the milk of transgenic mice. Yu2013 (mother-to-infant transmission)
b12: Predicted three-dimensional structures of functionally diverse gp120 proteins in their b12-bound conformation were characterized to better understand the gp120 determinants that expose or occlude the b12 epitope. Amino acid polymorphisms within the C2, C3, C4 and V5 regions of gp120 associated with augmented b12 binding. Residues in the b12-exclusive binding domain of gp120 that are important for b12 neutralization resistance were identified. Sterjovski2012 (antibody binding site, structure)
IgG1b12: 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)
b12: 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 CD4-binding site, heavy-chain-only type, b12 class, b12 family. Kwong2012 (review, structure, broad neutralizer)
b12: 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)
b12: Different adjuvants, including Freund's adjuvant (FCA/FIA), MF59, Carbopol-971P and 974P were compared on their ability to elicit antibody responses in rabbits. Combination of Carbopol-971P and MF59 induced potent adjuvant activity with significantly higher titer nAbs than FCA/FIA. There was no difference in binding of this MAb to gp140 SF162 with any of the adjuvants, as compared to the unadjuvanted sample. Lai2012 (adjuvant comparison)
b12: A nonfucosylated variant of b12 (NFb12) was developed to investigate antibody-dependent cellular cytotoxicity (ADCC) as a contributor to FcγR-associated protection. Compared to b12, NFb12 has enhanced FcγRIIIa-Mediated antiviral activity in vitro but did not improve protection against mucosal SHIV challenge in macaques. Moldt2012 (ADCC)
b12: This study shows that Env immunogens fail to engage the germline-reverted forms of known bnAbs that target CD4BS. However, the elimination of a conserved NLGS at Asn276 in Loop D and the NLGS at positions 460 and 463, located in variable region 5 of Env increased the binding and activation of VRC01 and NIH45-46. b12 was referred to as anti-CD4BS bnAbs. McGuire2013 (neutralization, antibody lineage)
b12: 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. Kovacs2012 (antibody binding site, neutralization, binding affinity)
b12: 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)
b12: 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. HIV-1 has developed steric constraints on the Abs binding to CD4BS. b12 has been used as a CD4BS binding Ab. The sensitivity of HIV-1 to b12 was enhanced by the altered gp41, J1Hx(66, 197). Haim2011 (antibody interactions)
b12: 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. b12 was used as BnAb to screen Env clones. wtR clone was resistant to b12, but N197H mutation caused 300 fold increase, Y384H and L702P caused 109 and 143 fold increase respectively in neutralization. ORourke2012 (neutralization)
b12: 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. b12 was used as a control bNAb. Sundling2012 (vaccine-induced immune responses)
b12: 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. b12 was used in BN-PAGE trimer shift assay and immunoprecipitation assay. Melchers2012 (neutralization)
b12: This paper describes immune-correlates analysis of an HIV-1 vaccine efficiency trial. In the RV144 trial the estimated efficacy was 31.2%. In this study a case-control analysis to identify Ab and cellular immune correlates of infection risk. Out of 17 Abs 6 were chosen for primary analysis to determine the roles of T cell, IgG Ab, IgA Ab responses. Assays were performed on 41 infected vaccinees and 205 uninfected vaccinees. b12 was used as a control in the HIV1 binding antibody multiplex assay. Haynes2012a (therapeutic vaccine, vaccine-induced immune responses)
b12: 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. b12 has been referred in discussing the breadth and potency of antiCD4 abs. West2012a (antibody lineage)
b12: 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. b12 was used to determine and compare the immunogenicity of homo and heterotrimers gp140s. b12 recognized clade B homotrimer better than clade A homotrimer. Sellhorn2012 (vaccine antigen design)
b12: 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. b12 was used as a control. Platt2012 (antibody interactions, glycosylation)
1b12: The use of computationally derived B cell clonal lineages as templates for HIV-1 immunogen design is discussed. 1b12 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)
b12: 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. b12 was used as a control to prove whether the purified and crystallized gp120 is in the CD4 bound conformational state or not. Kwon2012 (structure)
b12: mAbs with predetermined specificity were isolated from rhesus monkeys (RM) using differential biopanning method. Fluorescent mimotopes resembling V3 loop were used as baits to isolate single memory B cells. mAbs 33B2 and 33C6 were the best binders and neutralizers among 11 mABs. b12 was mentioned as a reference mAb to compare 33B2 and 33C6 activities. Sholukh2012 (mimotopes, neutralization, binding affinity)
b12: Polyclonal B cell responses to conserved neutralization epitopes are reported. Cross-reactive plasma samples were identified and evaluated from 308 subjects tested. b12 was used as a control mAb in the comprehensive set of assays performed. Plasma sample C1-0219 showed binding and neutralizing activities against native Env trimers similar to b12 and VRC03. D368R mutant trimers completely knocked out b12 and VRC03 but partially reduced C1-0219 binding. C1-0219 was unaffected by the W479G mutant suggesting that its nAbs are more akin to b12 than to VRC03. Tomaras2011 (neutralization, polyclonal antibodies)
b12: 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. b12 didn't exhibit strong binding to deglycosylated JRFL Env gp140. The authors inferred that glycan interferences control the binding of unmutated ancestor Abs of broad neutralizing mAb to Env gp41. Ma2011 (glycosylation, neutralization)
b12: 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. b12 was used as a control in neutralizing assay. Klein2012 (neutralization)
b12: 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. b12 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)
b12: 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. b12 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)
IgG1b12: 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. IgG1b12 has been mentioned to describe the sites of HIV-1 vulnerability; regarding the role of Fc region in neutralizing effect and CD4 immunogen designing. Recombinant antibody with Fc region knocked out of complement binding and ADCC activity had shown diminished protection. Kwong2011 (antibody binding site, neutralization, vaccine antigen design, review)
b12: 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. b12 was used as a control to compare the neutralizing activity of patients' sera. Lavine2012 (neutralization)
IgG1b12: 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. IgG1b12 (anti-CD4bs) is discussed in the context of developing broadly cross-neutralizing antibodies. Overbaugh2012 (escape, review)
b12: 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 b12 neutralization, whereas, 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)
IgG1b12: 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)
b12: 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 b12 was used for comparison. Walker2011a (neutralization, polyclonal antibodies)
b12: 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. Replacement of the V1V2 loop, but not V1 loop alone, in the neutralization-resistant escape variant by the corresponding region of the neutralization-sensitive virus resulted in a chimeric virus that was sensitive to neutralization by MAb b12, indicating that the V2 loop is involved in the neutralization resistance to MAb b12 of the neutralization-resistant escape variant. The introduction of a longer V1V2 loop with more PNGS of HIV-1 from contemporary seroconverters into the background of Env of HIV-1 from historical seroconverters resulted in a 2-fold increase in neutralization resistance to MAb b12 for 11/18 viruses. vanGils2011 (glycosylation, neutralization, escape)
IgG1b12: To improve the immunogenicity of HIV-1 Env vaccines, a chimeric gp140 trimer in which V1V2 region was replaced by the GM-CSF cytokine was constructed. We selected GM-CSF was selected because of its defined adjuvant activity. Chimeric EnvGM-CSF protein enhanced Env-specific Ab and T cell responses in mice compared with wild-type Env. Probing with neutralizing antibodies showed that both the Env and GM-CSF components of the chimeric protein were folded correctly. 3 proteins were studied: Env-wild-type, Env-ΔV1V2, Env-hGM-CSF. MAb b12 against discontinuous epitope associated with the CD4bs recognized Env-hGM-CSF, but the binding was subtly (4-fold) less efficient compared with that to Env-wild-type, suggesting that the CD4bs on Env-hGM-CSF is intact, but the accessibility and/or conformation of the b12 epitope is subtly altered by the replacement of the V1V2 domain by GM-CSF. vanMontfort2011 (vaccine antigen design)
IgG1b12: 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)
IgG1b12: 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. Although increased inhibitory activity was less clear for NAb b12 than for 447-52D, blocking the binding of b12 to the FcRs also induced a significant decrease of the inhibitory activity on LCs and IDCs. Neutralization with b12 Abs of the IgA type showed a potent inhibitory activity against HIV-1 replication in LCs and IDCs, but this activity was nevertheless lower than that for the corresponding IgG1. Peressin2011 (genital and mucosal immunity, dendritic cells)
IgG1b12: 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)
IgG1b12: 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. Binding of the covalent complex to MAb b12 was strongly reduced compared with gp140 alone. Martin2011 (mimics, binding affinity)
IgG1b12: 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. IgG1b12 and VRC01 had different neutralization potency and breadth, despite both of them recognizing the critical CD4-binding domain. IgG1b12 neutralized 45% (14/31) while VRC01 neutralized about 81% (25/31) of the viruses tested. Shang2011 (glycosylation, neutralization, subtype comparisons)
IgGb12: 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. b12 promoted shedding of >30% in 8/14 viruses. Ruprecht2011 (neutralization, kinetics)
b12: This is the first study to elicit NAbs by utilizing clones of native, sequential HIV-1 Env variants arising in vivo in an individual that developed broad NAbs over time. Rabbits were immunized using 3 vaccination strategies: (i) SF162 Env clone used to infect macaque A141 showing broad NAb response (clonal strategy); (ii) ordered immunization with 5 cocktails of Env sequences from 5 different time points from the same macaque (total 15 sequences) to recapitulate the changes in the viral quasispecies over time (sequential strategy); (iii) cocktail of same 15 Envs (mixture strategy). The sequential approach best replicated the features of the NAb response observed in that macaque. MAb b12 was used in immunofluorescence assay to measure expression of these 15 Envs at the cell surface. Malherbe2011 (vaccine antigen design)
b12: UCLA1 RNA aptamer was examined for its antiviral activity against HIV-1 subtype C viruses. Its efficacy was demonstrated by the high binding affinity for HIV-1 ConC gp120 and broad neutralization of primary isolates and Env-pseudotyped viruses. Mapping of the aptamer binding sites revealed 8 residues that modulated neutralization resistance to the aptamer. Most of the residues were localized within the CoRbs at the base of the V3 and the bridging sheet within the conserved V1/V2 stemloop of gp120 that makes up the CD4bs. The aptamer exhibited synergism with T20 fusion inhibitor and b12 MAb, with dose reduction indices indicating that lower concentrations of T20 and b12 can be used to inhibit HIV-1 when combined with the aptamer. Mufhandu2012
IgG1b12: Closely related HIV-1 B clade Envs from a pediatric subject in a late disease differed in their capacity to infect primary macrophages. E153G conferred high levels of macrophage infectivity for several heterologous R5 envelopes, while the reciprocal G153E substitution abrogated infection. Shifts in macrophage tropism were associated with dramatic shifts in sensitivity to the V3 loop MAb 447-52D and soluble CD4, as well as more modest changes in sensitivity to the CD4bs MAb, b12. Musich2011 (escape)
IgG1b12: 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)
b12: Using all-atom simulations, the role of the I109C/Q428C disulfide "stitch" in altering the conformational distribution of engineered HIV-1 gp120 core relevant for binding MAb b12 was studied. It was suggested that disulfide stitch shifts the conformational distribution of α1-helix to the unfolded state, meaning an unfolded α1 is not a strict requirement of the b12-bound conformational ensemble of gp120's lacking the I109C/Q428C stitch. Emileh2011 (structure)
b12:15 MAbs that block sCD4 binding to gp120 were studied. All CD4bs mabs tested blocked soluble CD4 binding to gp120 consistent with their designation as CD4bs directed antibodies. All CD4bs mabs tested neutralized pseudovirions carrying NL4.3 wild type envelope. However, only b12 failed to neutralize pseudoviruses carrying mutant envelopes with a blocked W100 pocket. In addition, for CD4bs mabs that neutralized pseudovirions carrying primary envelopes, mutation of the W100 pocket had little or no effect on neutralization sensitivity. The data indicate that the b12 W100 pocket on gp120 is infrequently targeted by CD4bs mabs and this site is therefore not a priority for preservation in vaccines aiming to elicit antibodies targeting the CD4bs. Duenas-Decamp2012 (neutralization)
b12: 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. Concerning b12, the most resistant clones of each subtype tested remained resistant and the most sensitive clones remained sensitive. Among the 11 tested clones (CRF01-AE, CRF01-AE 0858-M2, and clade B), only two clade B clones, 5008CL3 and 5008CL8, displaying a moderate sensitivity to b12 were found to be more sensitive after introduction of substitution I215M. Collectively, the IC50 of b12 toward wild-type or mutated clones were not significantly different. Thenin2012a (neutralization)
b12: 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 to inhibit mDC-mediated virus spread, compared with cell-free transmission. The IC50 and IC90 for b12, were significantly higher for almost all mDC-mediated virus transmission (Lai, NL4-3, Lai/Balenv and 89.6), compared with cell-free HIV-1 infection. mDCs transferred significantly less virus to target cells when exposed to Lai virus particles in the presence, as opposed to the absence, of b12 suggesting that mDC-mediated virus transfer can be inhibited by b12 if it is present at the time of virus capture by mDCs. Examining the susceptibility of mDC-mediated trans-infection to the b12 Fab, both Lai and Lai/Balenv were suppressed equivalently by b12 irrespective of whether target cells were challenged with cell-free or mDC-associated virus particles. 4E10 and 2F5 bound a significantly greater percentage of mDCs, compared with b12. All abs bound a significantly greater percentage of mDCs, compared with the secondary antibody alone. Lai and Lai/Balenv required significantly higher b12 4E10 concentrations to block mDC-mediated versus cell-free infection of autologous T cells. Sagar2012 (neutralization, binding affinity)
b12: 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)
b12: 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)
b12: 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. There was an ∼50% increase in b12 binding, in agreement with previous studies showing that glycans, in particular the one at position 386, can restrict access to the b12 epitope. Depetris2012 (glycosylation, binding affinity)
b12: 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. b12 bound very strongly to the gp120 core and RSC3; very weakly to RSC3/G367R and did not bind to gp120 core D368R, RSC3 Δ3711, and RSC3 Δ3711/P363N. Lynch2012 (binding affinity)
b12: 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). Borggren2011 (glycosylation, neutralization)
b12: MAbs 4E10 and b12 were examined for antibody-dependent neutralization, or antibody-dependent complement (C)-mediated neutralization, of infection of PBMC by either free HIV-1 or trans infection by HIV bound to erythrocytes. Neutralization of free HIV-1 by b12 was stronger than by 4E10, but b12 neutralized erythrocyte-bound HIV-1 less efficiently than cell-free virus. 4E10 did not neutralize erythrocyte-bound HIV-1 and at a low concentration it caused enhancement of infection. Antibody (4E10)-dependent C activation inhibited trans infection by erythrocyte-bound HIV-1, but caused enhanced infection with cell-free HIV-1 in the presence of erythrocytes. No effects of C were observed with b12. Beck2011 (neutralization)
b12: The interaction of the lectin griffithsin (GRFT) with HIV-1 gp120 and its effects on exposure of the CD4-binding site (CD4bs) was studied. GRFT enhanced the binding of HIV-1 to b12 and b6 or the CD4 receptor mimetic CD4-IgG2. The average enhancement of b12 or b6 binding was higher for subtype B viruses than for subtype C. The glycan at position 386, which shields the CD4bs, was involved in both GRFT-mediated enhancement of binding and neutralization synergism between GRFT and b12. Alexandre2011 (antibody binding site, glycosylation)
b12: The strategy of incorporating extra glycans onto gp120 was explored, with the goal to occlude the epitopes of non-neutralizing MAbs while maintaining exposure of the b12 site. The focus was on the head-to-head comparison of the ability of 2 adjuvants, monophosphoryl lipid A (MPL) and Quil A, to promote CD4-specific Ab responses in mice immunized with the engineered mutant Q105N compared to gp120wt. Neutralizing and non-neutralizing antibodies targeting three areas on gp120 – the CD4bs (F105, b6, b12, b13, VRC01, VRC03 and CD4- IgG2), the glycosylated ‘silent face’ (2G12) and the V3 loop (B4e8) – were assessed for binding. The antibodies b6, b12, b13, VRC01 and 2G12 bound best to mutant Q105N, albeit with lower affinities than to gp120wt. Retention of b6 and b13 binding was not expected, but can be explained by their very similar mode of interaction with the CD4bs compared to b12. Abs F105 and VRC03 did not bind Q105N at all. The V3-specific antibody B4e8 did not bind to Q105N. Ahmed2012 (adjuvant comparison, antibody binding site, glycosylation, neutralization, escape)
b12: The study showed that adeno-associated virus (AAV)-BnAb gene transfer to cervico-vaginal epithelial cells can lead to protection against HIV-1. A recombinant AAv vector that encodes h12 as a single-chain variable fragment Fc fusion, or "minibody" was constructed. The minibodies secreted from transduced cells in an organotypic vaginal epithelial cell model demonstrated their ability to inhibit transfer and infectivity of HIV-1 at levels comparable to full-length b12 MAb. Abdel-Motal2011 (genital and mucosal immunity)
b12: The study followed the dynamics of alternating viral neutralization phenotype over time in 7 patients monitored for 1-5 years starting from seroconversion. While the development of neutralization resistance, including escape from the autologous antibody response was observed, there was also temporal emergence of viruses exquisitely sensitive to both autologous and heterologous Nabs. All Envs with heightened serum sensitivity were also potently neutralized by sCD4 and/or IgG1b12. Aasa-Chapman2011 (autologous responses, escape)
b12: 6 "chimeric" scFv b12 variants were generated by sequentially replacing HV, HD(J), VH and VL segments in b12 germline-like predecessor with the mature counterparts. A single Y/D mutation in HD-segment was enough to make the transition of non-binding-germline-like b12 Ab to a binding Ab to HIV-1 Env, but this mutation was not enough to confer neutralization activity to the germline antibody. Chimeric scFv b12 variants required mature VL to neutralize the virus. Yuan2011 (neutralization, antibody lineage)
b12: 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. MAb b12 bound mature and immature virions to an equivalent extent, although the CT-deleted Env bound significantly more MAb b12 when present on immature vs. mature particles. It suggested that the epitope recognized by b12 was exposed to a similar extent on mature and immature HIV-1 particles and that the gp41 CT appears to modulate exposure of this epitope differentially on mature vs. immature particles. Joyner2011 (binding affinity)
b12: 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)
b12: 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. Infants P1031, P1046 and P1049 had some clones resistant to b12, but each had one sensitive clone. A similar pattern of sensitive and resistant clones was seen in the corresponding mothers. Kishko2011 (neutralization, mother-to-infant transmission)
b12: 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. All maternal and infant clones from MIPs (mother-infant pairs) 0377, 0978 and 1021, displayed a high level of resistance to neutralization by MAb b12, whereas the two maternal clones from pair 0858 were highly sensitive to b12. Thenin2012 (neutralization, mother-to-infant transmission)
b12: 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. The cyclic permutant V1cyc were used to incorporate the trimerization domains. In contrast to monomeric gp120, h-CMP-V1cyc (a covalently linked trimer) interacted with similar affinities to both b12 and F105. SUMO2a-V1cyc (a mixture of a trimer, a dimer, and a monomer) binds approximately 5-10-fold weaker than gp120 to b12 and F105. It has been shown that V1 cyclic permutants of gp120 with an appropriate trimerization domain can fold into a conformation that shows improved affinity for b12 relative to gp120. Saha2012 (binding affinity)
b12: 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. Replicating viruses generated in primary lymphocytes were most resistant to neutralization by most monoclonal antibodies including b12. PBMC-derived chimeras displayed increased neutralization resistance compared to 293T-derived chimeras for b12. Provine2012 (neutralization)
b12: Epitope accessibility of the gp41 neutralizing antibodies, 2F5 and 4E10, is explored either on the functional spike or during receptor-mediated entry and it is determined if these antibodies bind to the static spike on the surface of the HIV-1 or require target cell/receptor engagement to gain access to their MPER binding sites. JR-FL virus was neutralized by b12, a gp120-specific CD4 binding site antibody, either without or with any antibody-virus wash step over a broad range of concentrations. The potent neutralization exerted by b12 even after the antibody-virus washing confirmed high-affinity binding and indicated that b12 could directly access its epitope on the prereceptor-engaged viral Env spike. Chakrabarti2011 (antibody binding site, neutralization)
b12: Phenotypic activities of a single transmitted/founder (T/F) virus from 24 acute individuals were compared to that of 17 viruses from chronics. T/F Envs were more sensitive than chronic Envs to MAbs b12 and VRC01. The binding of b12 and VRC01 to the trimeric Envs was strongly correlated to their sensitivity to inhibition for both T/F and chronic viruses. Binding of b12 to the T/F was significantly increased relative to chronics. Wilen2011 (neutralization, binding affinity)
b12: 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. b12 was included for comparison and neutralized 29% of contemporary viruses at IC50 < 1 μ g/ml and 52% 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 b12. Euler2011 (neutralization)
b12: 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. D279A substitution did not substantially affect neutralization by b12 and I420A and I423A substitutions actually increased b12 neutralization. Falkowska2012 (neutralization)
b12: 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 b12 neutralized 34% 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 that of b12, 2G12 and 4E10. Walker2011 (neutralization, broad neutralizer)
b12: Broadly neutralizing HIV-1 immunity associated with VRC01-like antibodies was studied by isolation of VRC01-like neutralizers with CD4bs probe; structural definition of gp120 recognition by RSC3-identified antibodies from different donors; functional complementation of heavy and light chains among VRC01-like antibodies; identification of VRC01 antibodies by 454 pyrosequencing; and cross-donor phylogenetic analysis of sequences derived from the same precursor germline gene. b12, among with other RSC3-reactive antibodies, was used for several comparisons and showed dramatic differences in heavy-chain orientation relative to the VRC01. b12 had 48-66% sequence identity of its heavy and light chains to respective chains of VRC-PG04 and VRC-CH31. Wu2011 (structure)
b12: 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. Cells transduced with GPI-CDR H3(b12) had minimum neutralization activity against 2 (Q168 and Yu2) of the 24 HIV-1 pseudotypes with a low degree of potency. Compared to mock-transduced parental TZM-bl cells, cells transduced with GPI-CDR H3(b12) did not show any significant neutralization activity against any of 3 HIV-1 strains and SIVMne027 control. Liu2011 (neutralization, variant cross-reactivity)
b12: 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. I424M substitution in JRFL, RHPA4259.7 and YU2 Envs (3 out of 5) conferred increase in b12 sensitivity by 2, 3.8 and 32.27 folds respectively compared to the Envs expressing M424. Ringe2011 (neutralization)
b12: Two SHIV-C mutants were designed: SHIV-1157ipEL-pΔ3N, a mutant of the early SHIV-1157ipEL-p which lacked the 3N residues in the V2 stem, and SHIV-1157ipd3N4+3N, a mutant of the late SHIV-1157ipd3N4 where 3N residues was added in the V2 stem. While the early SHIV-1157ipEL-p was neutralized and bound by b12, its mutant SHIV-1157ipEL-pΔ3N was not. Moreover, b12 did not neutralize and bind to the late SHIV-1157ipd3N4 but neutralized and bound the mutant SHIV-1157ipd3N4+3N. 3N deletion mutation in the V2 loop stem of gp120 was identified as the major determinant of neutralization escape of b12. The b12 epitope was present in the early and late SHIV-Cs. b12 interacts mainly with the outer domain of gp120, but the position of the V2 loop masks the epitope in the late SHIV-1157ipd3N4. Watkins2011 (neutralization, binding affinity)
b12: Human MAbs b12 and b6 against CD4bs on HIV-1 gp120 and F240 against an immundominant epitope on gp41 were assessed for prevention of vaginal transmission of simian SHIV-162P4 to macaques. Applied vaginally at a high dose, the strongly neutralizing MAb b12 provided sterilizing immunity in 7/7 animals, which was statistically significant compared to control animals. Burton2011 (genital and mucosal immunity, immunoprophylaxis, neutralization, binding affinity)
b12: 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 sensitive to neutralization by MAb b12 while the LN40 Env, having the opposite phenotype of B33, is resistant to MAb b12. Additional mutations were created within known b12 binding pockets that decreased neutralization of the vaccine sera by about 10 percent individually, but the combination mutants LN40KD (R373K plus N386D) and LN40KV (R373K plus T388V) almost inhibit the neutralization of the vaccine sera. Vaine2011 (neutralization)
b12: 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. b12 had very low neutralization potency for 2 (Q168b23 and Q842d16) out of 8 pseudoviruses in the panel, no neutralization potency for 2 (BJ613.E1 and BF535.A1) and high for the rest of them. Lynch2011 (neutralization, variant cross-reactivity, mother-to-infant transmission)
IgG1b12: 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)
b12: 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 increased the b12 neutralization sensitivity by ∼10-fold or more compared to viruses with only mutation at position 675. There was no effect on b12 neutralization sensitivity by only T569A change. The change at position 675 alone had no effect on b12 binding in contrast to an increase in b12 binding observed with T569A change alone and both mutations. Lovelace2011 (antibody binding site, neutralization, variant cross-reactivity, binding affinity)
b12: A strategy is described for eliciting antibodies in mice against selected cryptic, conformationally dependent conserved epitopes of gp120 by immunizing with multiple identical copies of covalently linked multiple copy peptides (MCPs) representing 3 different domains of gp120. Preincubation of gp120 with high concentrations of MAb b12 to the 426-441 epitope resulted in a much higher inhibition of CD4 binding to gp120, than achieved by the MAb 11A8. b12 bind to gp120s from other clades with lower affinities compared to clade B reflecting differences in the primary sequences. MAb 11A8 demonstrated a similar breadth of binding to oligomeric gp120 on cells infected with viruses from different clades, and actually detects virus at a higher intensity and on more cells infected with a clade D isolate than does the MAb b12. Kelker2010 (binding affinity)
b12: To address the controversy of significant differences in chosen atomic coordinates of monomeric SIV gp120 in unliganded, and monomeric HIV-1 gp120 in various liganded and antibodybound states, the molecular architectures of trimeric Env from SIVmneE11S, SIVmac239 and HIV-1 R3A strains are shown to be closely comparable to that previously determined for HIV-1 BaL. The gp120 density profiles obtained from the coordinates of the trimeric Env complex with sCD4/17b (1GC1) and b12 (2NY7) are similar even though there are important differences in their atomic resolution structures. White2010 (structure)
IGg1b12: 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. The neutralization of SHIV-1157ipEL (clade C) and SHIV-1157ipEL-p (clade C) was similar and much higher than SHIV-1157ipd3N4 (clade C) and SHIV-SF162P3 (clade B) by IGg1b12. SHIV-2873Nip (clade C) was not neutralized although SHIV-SF162P4 (clade B) was highly neutralized by IGg1b12. In another experiment, b12 neutralized SHIV-1157ipEL-p although SHIV-1157ipEL-pΔ3N and SHIV-1157ipd3N4 were not neutralized even at the highest nmAb concentration tested. Siddappa2010 (neutralization, vaccine antigen design, subtype comparisons)
b12: The location and extent of conservation of eight protease cleavage sites on HIV-1 gp120 recognized by 3 major human proteases (cathepsins L, S and D) are described along with the effect of cathepsin cleavage on gp120 binding to CD4-IgG and NAbs. Most of the b12 binding was preserved with cathepsin L-treated gp120 although significant reduction in binding affinity was observed. There was also a large reduction in b12 binding with cathepsin D-treated gp120. Yu2010 (binding affinity)
b12: 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)
IgGb12: 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 b12 neutralizes about half of the viruses, including different clade isolates. In vivo, intravenously or vaginally administered b12 can protect macaques from SHIV infection through vagina. Gonzalez2010 (neutralization, variant cross-reactivity, escape, review)
b12: 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 and Genetic approaches. Walker2010a (neutralization, review)
b12-IgG1: 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. b12 was mentioned in context of engineering immunity: program human B cells using autologous human hematopoietic stem/progenitor cells transduced with the b12-IgG1 gene for differentiation into antibody secreting cells. Tomaras2010 (review)
b12: Crystal structures of gp120 and gp41 in complex with CD4 and/or MAbs 17b, 48d, b12, b13, 412d, X5, 211C, C11, 15e, m6, m9 and F105 were used to determine the structure and the mobility of the gp41-interactive region of gp120. Elements determined to maintain the gp120-gp41 interaction were the gp120 termini and a newly described invariant 7-stranded β-sandwich. Structurally plastic elements of gp120 responsible for the various gp120 conformation changes due to receptor- or Ab-binding were structured into 3 layers, with the V1/V2 loops emanating from layer 2 and the highly glycosylated outer domain from layer 3. Pancera2010a (antibody binding site, structure)
b12: 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. In contrast to clade B and African clade C viruses, Env clones from 4/5 Indian patients were resistant to b12. For the one patient whose clones Env clones were neutralized by b12, the increased neutralization sensitivity did not correlate with their sensitivity to sCD4 and contemporaneous plasma antibodies. Ringe2010 (neutralization)
b12: 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)
b12: 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 b12 MAb. Only 2/34 viruses showed low b12 susceptibility and all viruses contained the P369L mutation previously shown to contribute to b12 resistance. Nie2010 (neutralization)
b12: 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 b12. Pluckthun2010 (review, antibody polyreactivity)
b12: 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. b12, however, did not neutralize any of the mutants tested. ORourke2010 (neutralization, variant cross-reactivity)
b12: Susceptibility of Env chimera viruses from six mother and infant pairs (MIPs) to b12 neutralization was evaluated. b12 neutralized 7/24 infant viruses and 12/25 maternal viruses. Interpair differences to b12 susceptibility were observed and there was a marginally significant difference in the susceptibility to b12 between maternal and infant viruses, with infant viruses being more resistant. Zhang2010a (neutralization, mother-to-infant transmission)
b12: MAb m9 showed superior neutralization potency compared to b12 in a TZM-bl assay, where it neutralized all 15 isolates compared to b12 that neutralized only 60% of the isolates tested and did not neutralize any subtype A isolates. In the M7-Luc assay, b12 neutralized 56% of clade C isolates while m9 neutralized 76%. In vitro passaging of HIV-1 in the presence of b12 resulted in emergence of escape mutants to this Ab. Zhang2010 (neutralization, escape)
b12: 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. Profile differences between the three vaccine trials when it comes to CD4bs-Abs were observed. Only 33% of sera from the HVTN 203 or the HVTN 041 trial were able to outcompete binding to b12, while 95% of sera from the DP6-001 trial were able to outcompete binding to this MAb and did so with significantly higher titers. Vaine2010 (antibody interactions)
b12: 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)
b12: A mathematical framework is designed to determine the number of Abs required to neutralize a single trimer called the stoichiometry of trimer neutralization (N). 15 different virus antibody combinations divided into five groups based on antibody binding sites were used in the designed model. b12 was classified into CD4BS group as it interferes with CD4 binding site. The number of b12 Abs needed to neutralize a single trimer was determined to equal 1. Magnus2010
IgG1b12: SHIV challenge model was used in macaques to determine if viremia and T cell destruction could be reduced with low amounts of NAbs. IgG1b12 was incorporated with SHIVIG in 6 macaques before oral challenge with SHIV-SF162P3. Treated macaques rapidly developed NAbs and displayed significantly reduced plasma viremia. In addition, treated macaques showed rapid ADCVI responses. Ng2010 (immunoprophylaxis)
IgG1b12: 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)
b12: 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 usage of b12-like epitope in the subject's antisera was examined with many mutant gp160 variants. All the variants along with the wild type gp160 were neutralized with similar efficiency by b12. Additionally, T257A and WT gp160s were also neutralized equally by b12. Nandi2010 (neutralization)
b12: The antigenic structure of Gag-Env pseudovirions was characterized and it was shown that these particles can recapitulate native HIV virion epitope structures. b12 bound to the BaL Gag-Env pseudovirions, indicating presence of native trimers. The Gag-Env pseudovirions were further used to identify a subset of antigen-specific B cells in chronically infected HIV subjects. Hicar2010 (binding affinity, structure)
b12: 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 b12 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)
b12: Virus capture assay was modified with added incubation of virions and MAbs in solution followed by removal of unbound MAbs, which allowed for relative affinity of b12 for virions to be quantified. b12 did not show any Env-independent virus capture. There was an overall reduction in the efficiency of capture of molecular clones (MC) relative to pseudotyped virions by b12. MAb competition assays revealed that b6 competed poorly with b12 for capture of virus containing mainly native Env trimers. Denaturation of the trimers resulted in b6 inhibition of b12 capture, and b12 was poor at blocking virion capture by b6, indicating higher affinity of b6 for uncleaved gp160 compared to b12. However, trimeric JR-FL MC was not captured more efficiently by b12 than nontrimeric Envs from JR-CSF MC virus. Leaman2010 (assay or method development, binding affinity)
b12: 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)
b12: 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)
b12: 18 unique Env clones of subtype C HIV-1 derived from six African countries and Scotland were tested for their neutralization susceptibility by b12. b12 neutralized 6/18 isolates (30%). Koh2010a (neutralization)
b12: Peptide ligands for CD4i epitopes on native dualtropic Envs were selected by phage display. The correct exposure of CD4i epitopes was detected by binding with MAb b12, which bound both in the presence or absence of sCD4. Dervillez2010 (binding affinity)
b12: Impact of in vivo Env-CD4 interactions was studied during vaccinations of Rhesus macaques with two Env trimer variants rendered CD4 binding defective (368D/R and 423/425/431 trimers) and wild-type (WT) trimers. Ab binding profiles of the three trimer variants were assessed by binding analyses to different MAbs. CD4bs-directed MAb b12 bound similarly to WT and 423/425/431 trimers but did not bind to 368D/R trimers. b12 cross-competitive Abs were elicited by WT or 423/425/431 trimers in all tested animals at several dilutions, but were only elicited by 368D/R trimers at the lowest dilution of the plasma. Douagi2010 (binding affinity)
b12: 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 significantly affect the neutralization by b12 and did not affect the binding affinity to b12. D368R modification to SF162gp120 abrogated binding by b12, although it did not affect the neutralization by b12. Ching2010 (neutralization, binding affinity)
b12: The effect of HIV-1 complement opsonization on b12 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. b12 was not able to inhibit HIV-1 transcytosis. b12 inhibited the attachment of non-opsonised HIV to iMDDC but had no effect on the opsonized HIV-1 attachment. b12 was able to inhibit production of both opsonized and non-opsonized HIV-1 in iMDDCs. Jenabian2010 (complement)
b12: 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 b12) 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 two out of three clusters did not correlate with sensitivity to b12. Doria-Rose2010 (neutralization)
b12: 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)
b12: Addition of bacterial endotoxin (LPS) had no effect on the potency of b12 neutralization in TZM-bl assay but addition of LPS in PBMC assay increased neutralization potency of b12. 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)
b12: 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 b12, 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 b12 on virus infectivity. Significant variation in sensitivity to b12 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)
b12: Expression of gp120 was shown to lead to the accumulation of both monomeric gp120 and aberrant dimeric gp120 forms. Dimeric forms of gp120 were recognized by CD4BS MAbs, such as b12, but were not recognized by CD4i MAbs or MAbs to the gp120 inner domain. It is suggested that gp120 dimerization occludes or disrupts the inner domain and/or the co-receptor binding site. Formation of gp120 dimers was reduced by removal of the V1/V2 loops or the N and C termini. Finzi2010 (antibody binding site)
b12: 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)
b12: Subtype B HIV-1 variants from historical seroconverters (individuals that seroconverted between 1985 and 1989) were shown to be more sensitive to neutralization by b12 than variants isolated from contemporary seroconverters (individuals that seroconverted between 2003 and 2006). The enhanced resistance of the virus to Ab neutralization over time coincided with poorer elicitation of neutralizing Ab responses, increase in the length of the variable loops, and increase in the number of potential N-linked glycosylation sites on gp120. Bunnik2010a (glycosylation, neutralization, dynamics)
b12: 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 b12, neutralizing 100% of HIV-1 primary isolates of subtypes A, B, C, D, F, CRF01_AE and CRF02_AG, while b12 neutralized some isolates of subtypes A, B, C and D. Lagenaur2010 (neutralization, variant cross-reactivity, subtype comparisons)
b12: Crystal structure of the D7 llama heavy chain antibody fragment V(HH) was resolved and compared to other CD4bs Abs (b12, b13, F105 and m18). Unlike for b12 and b13, CDR2 of D7 did not have aromatic residues at the tip and does not play a prominent role in gp120 interactions. As b12 and the other CD4bs Abs, D7 had aromatic residues at the tip of its CDR3. Other than that, there was no significant structural homology between D7 and other CD4bs Ab loops, underlining the differences in mode of gp120 interaction. Hinz2010 (structure)
b12: 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. b12 neutralized uncleaved ΔV1V2 variants more potently compared to the wild type virus, but bound to the cleaved and uncleaved ΔV1V2 variants less efficiently compared to the full-length protein. Bontjer2010 (neutralization, binding affinity)
b12: Optimized peptide mimetics of gp41 prehairpin intermediates were constructed to induce neutralizing responses in vaccinated guinea pigs and rabbits. Neutralization potency of sera from animals immunized with covalent trimeric immunogens was greater than the potency of sera from animals immunized with noncovalent trimers. Sera from animals immunized with longer constructs was more neutralizing than antisera from shorter constructs. Sera from immunized guinea pigs, but not from rabbits, neutralized half of the Tier 1 viruses tested. For the analyses, a mutant virus (HXB2-V570A) was used, which is hypersensitive to Abs binding to the pre-hairpin intermediate but not to mAbs that bind elsewhere. This was supported by neutralization analyses with b12, where this Ab neutralized HXB2-V570A and HXB2 wild type viruses equally well. Bianchi2010 (mimics, neutralization)
b12: 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 was tested using the known neutralizing Abs. There was no significant effect on b12 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. b12 did not recognize the epitopes only when the virus is treated with INA and UV for 15 minutes which is reversed by adding glutathione. This suggests that INA treatment was not reason for the loss of b12 recognition. Belanger2010 (binding affinity)
b12: 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)
b12: Parent and GnTI (complex glycans of the neutralizing face are replaced by fully trimmed oligomannose stumps) viruses were equally sensitive to neutralization by b12, indicating that replacement of complex glycans does not affect the already exposed b12 epitope. Absence of the glycan at residue N301 (N301Q mutant virus) had only a small effect on b12 neutralization. Sensitivities of viruses treated with neuraminidase to b12 were similar to those of untreated viruses, indicating that terminal sialic acid moieties on complex glycans do not affect neutralization sensitivity. The ability of b12 to complex with and deplete Env trimers on blue native polyacrylamide gel electrophoresis (BN-PAGE) correlated with its ability to neutralize. Binley2010 (glycosylation, neutralization, binding affinity)
IgGb12: This human Ab was compared to the Abs derived from B-cell cultures from SHIV-infected rhesus macaques and human MAbs 2909 and 3.9F. b12 captured SF162, SF162ΔV1, SF162ΔV2 and SF162ΔV3 viruses. Robinson2010 (binding affinity)
b12: An outer domain (ODec) based immunogen including the whole outer domain and most of the CD4 binding residues was designed and expressed in E-coli bacterial cells. The ODec lacked V1V2 and V3, incorporated 11 designed mutations at the interface of the inner and outer domains of gp120, and was unglycosylated. b12 bound to both ODec and to monomeric gp120. Structural analyses showed that all residues required for b12 binding were present in ODec. Sera from rabbits immunized with ODec neutralized 4/5 clade B and 1/2 clade C viruses. Bhattacharyya2010 (kinetics, binding affinity)
b12: 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 b12. Yoshimura2010 (mimics, neutralization)
b12: Two N-glycosylation sites in the V2 and C2 regions of Env (N186 and N197) were shown to play a role in regulating susceptibility of CRF01_AE viruses to neutralization by b12. Removal of N186 increased susceptibility of two resistant CRF01_AE viruses to b12 neutralization. Removal of N197 in two resistant viruses lacking N186 resulted in their increased susceptibility to b12 neutralization. In resistant viruses with both N-glycosylation sites present, removal of both N186 and N197 resulted in increased b12 susceptibility, while removal of either site alone was not sufficient for change in susceptibility to b12 neutralization. Utachee2010 (glycosylation, neutralization, escape)
b12: Neutralizing sensitivity of L669S mutant virus to b12 was not significantly different from the neutralizing sensitivity of the wild type virus. Shen2010 (neutralization)
b12: Neutralization potency of b12 was compared to that of HK20 scFv in TZM-based assay using 45 Tier 1 and Tier 2 HIV isolates. b12 neutralized 27/45 isolates. In addition, b12 was used in TriMab, together with 2F5 and 2G12, 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)
b12: Substitutions in the CD4bs (E370A and/or D368A) or in close proximity to the CD4bs (N276A, R480A and Y384A) reduced binding of b12 but had no effect on binding activity of anti-core MAbs, indicating that binding characteristics of the anti-CD4bs Ab and anti-core Abs are distinct. Three mutations, D747A, M475A and R476A, had no effect on b12 binding but they generally reduced binding of anti-core MAbs. b12 bound to both gp160 trimer lacking the cytoplasmic domain and to gp140 with high affinity, and it retained high affinity binding to gp160 or gp140 with the three mutations. Pietzsch2010a (variant cross-reactivity, kinetics, binding affinity)
b12: 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 Q363 mutation, which inhibited neutralization by b12 fivefold. Strong binding competition between patient sera and b12 was observed. Huang2010 (antibody interactions, escape)
b12: In 7/15 individuals b12 sensitive viruses were present early in infection but were replaced by b12 neutralization resistant variants during the late stages of infection. In one of the patients, the b12 resistance could be mapped to a combination of amino acid residues at positions 154 (I to M), 178 (K to T) and 389 (Q to P, L or K). b12 resistance correlated with increased virus replication kinetics, but the three resistance mutations did not. Instead, they reduced the replication capacity of the LAI strain. It was also shown that the b12 resistant variants emerged in the absence of humoral or cellular immune pressures. Bunnik2010 (neutralization, escape)
b12: Phylogenetically corrected computational statistical methods were used to identify amino acid positions related to NAb phenotypes. b12 was used for validation of these methods. The signature analyses identified 10 signature sites that were related to b12 neutralization phenotypes. Eight of the sites were in gp120, and seven of those have previously been shown critical in the b12 epitope. Amino acids associated with b12 resistance were: H or S in position 173, G, S or T in 185, K or R in 268, A or H in 364, and I, L or Q in 369. Additional two signature sites were found in gp41, 651 (aa D, I or S associated with resistance to b12) and 655. Both of these sites co-varied with sites in gp120, and are suggested to affect the exposure of the b12 epitope in the quaternary structure of Env. Gnanakaran2010 (neutralization, escape)
b12: b12 was used as a negative control in assessment of binding of 4E10 and 4E10 variants (with nonconservative substitutions of tryptophan in the CDRH3 region) to viral membrane mimetic liposomes. 4E10 Asp variants exhibited similar responses on VM liposomes as b12. Scherer2010 (binding affinity)
b12: The specificities and structural analyses of b12 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)
b12: Neutralization of three SHIV viruses, SHIV89.6P, SHIVsf162P3 and SHIVBa-L, by b12, 2F5 and 4E10 was estimated. SHIVBa-L was most sensitive to neutralization by b12, 4E10 and 2F5. Antibody-dependent cell-mediated virus inhibition (ADCVI) of b12, 2F5 and 4E10 was compared. b12 was more effective than 2F5 and 4E10 at ADCVI in vitro. Hessell2010 (neutralization)
b12: 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. b12 binding and neutralization activity was compared to the three new broadly neutralizing mAbs. b12 competed for binding to gp120 with 9 of the new mAbs. b12 neutralized 80% of Tier 1 and 43% of Tier 2 viruses, the neutralization of Tier 2 viruses being comparable to that of the new MAb HJ16. b12 did not, however, neutralize the same Tier 2 viruses as HJ16. b12 rarely neutralized clade A isolates. Corti2010 (neutralization, binding affinity)
b12: b12 x-ray scattering data was used to determine global structure of this Ab. The results showed that b12 assumes a rigid asymmetric disposition of the two Fab arms relative to Fc. It is suggested that b12 cannot adopt a wide range of conformations, and the results agreed with b12 crystal structure analyses. Solanki2010 (structure)
b12: 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. b12 was used as a control and it neutralized 4/5 Tier 1 and 3/5 Tier 2 viruses. Scheid2009 (neutralization)
b12: Exogenous epitope tags were introduced in different parts of three variable regions, V1, V2 and V4, of two HIV isolates, SF162 and SF33. All tagged viruses were highly susceptible to neutralization by b12, suggesting that the overall exposure of CD4bs was not affected by tagging. Wallace2009 (antibody binding site)
b12: 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)
b12: The structure and dynamic of the virion spike and the CD4-binding site are discussed. Data revealing steric barriers around the CD4bs, such as variable loops, glycans and neighboring protomer, and their impact on b12 binding are reviewed. Implications of the data for immunogen design is discussed. Schief2009 (antibody binding site, review)
b12: 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. In several cases the PBMC assay was more sensitive for inhibition by b12, but the differences between PBMC and TZM-bl assays were less pronounced compared to other MAbs studied. Rusert2009 (assay or method development, neutralization)
b12: 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 HA-tagged viruses to b12 was similar to the neutralization sensitivity of wild type virus to this Ab. Pantophlet2009 (neutralization)
b12: 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. Strain-specific and binding properties of b12 and b13 are discussed. 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 (antibody binding site, autologous responses, review)
b12: 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 b12. Importance of identification and characterization of new epitopes, and of B-cell stimulation, is discussed. Montefiori2009 (review)
b12: 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 neutralizing capacity of b12. gp120 point mutation D368R was used to screen the sera for CD4bs- Abs, as it was shown that this mutant could not adsorb binding activity of b12. The gp120-eluted IgG was shown to specifically compete with b12 for binding to gp120, indicating presence of CD4bs Abs. To test for presence of coreceptor binding region MAbs in sera, gp120 I420 mutant was used. This mutant was recognized by b12 at equal levels as the wild type, and it could adsorb binding activity of b12 in adsorption assay. 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)
b12: b12 heavy chain-only 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)
b12: 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 b12, is displayed. Korber2009 (review)
b12: Continuous treatment of macaques with low dose b12 or b12 LALA variant, which has similar neutralizing activity as b12 but does not mediate Fc effector functions, provided significant difference in protection against low dose challenge compared to controls. Treatment with b12 reduced infection risk at each challenge by a factor of 21 and treatment with LALA by a factor of 10. There was a significant difference between peak viremias in the b12 and LALA treated macaques. Hessell2009a (immunoprophylaxis)
b12: The effect of continuous b12 infusion on protection from infection and on viral load is reviewed. Haigwood2009 (immunoprophylaxis, review)
b12: FcγR-mediated inhibition and neutralization of HIV by b12 and other MAbs is reviewed. The review also summarizes the role of ADCC and ADCVI Abs, including b12 ADCVI activity, on HIV infection protection. Forthal2009 (review)
b12: 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. All variants were highly sensitive to neutralization by b12, but complete neutralization was not achieved even at high b12 concentrations. Bontjer2009 (antibody binding site, neutralization)
b12: This review summarizes novel approaches to mapping broad neutralizing activities in sera and novel technologies for targeted MAb retrieval.