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MAb ID	3BNC117 (3BNC117_dRU3)
HXB2 Location	gp160	gp160 Epitope Map
Author Location	Env
Epitope
Ab Type	gp120 CD4BS
Neutralizing	P (tier 2) View neutralization details
Contacts and Features	View contacts and features
Species (Isotype)	human(IgG)
Patient	Patient 3
Immunogen	HIV-1 infection
Country	United States
Keywords	acute/early infection, ADCC, antibody binding site, antibody generation, antibody interactions, antibody lineage, antibody polyreactivity, antibody sequence, assay or method development, autologous responses, binding affinity, broad neutralizer, chimeric antibody, computational epitope prediction, contact residues, elite controllers, escape, genital and mucosal immunity, glycosylation, HAART, ART, HIV reservoir/latency/provirus, immunoprophylaxis, immunotherapy, junction or fusion peptide, mutation acquisition, neutralization, polyclonal antibodies, review, structure, subtype comparisons, vaccine antigen design, vaccine-induced immune responses

Notes

Showing 73 of 73 notes.

3BNC117: 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)
3BNC117: 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 3BNC117 were used for comparison purposes. Zhang2022 (neutralization, immunotherapy, broad neutralizer)
3BNC117: An elite HIV-controlling patient SA003 was found to have a high level of serum bNAb activity, and broadly neutralizing mAb LN01 IgG3 was isolated from patient serum. MAb 3BNC117 was used as a comparison in an assay of ADCC. Pinto2019 (ADCC)
3BNC117: 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)
3BNC117: 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)
3BNC117: 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. Analysis of generated cyroEM structure of BG505 SOSIP.664-3BNC117 (resolution of ˜4.4A) revealed that residues in 3BNC117 HFR3 interact favorably with binding site elements including H71a with N197 glycan and W71d with Env 308 (32%R & 39%H) on the adjacent gp120 protomer. Comparison with generated cryoEM structure of BG505 SOSIP.664-3BNC117-PGT145 (resolution of ˜4.3A) revealed that 3BNC117-binding induced subtle increase in spacing between N160 glycan triad which would provide greater apical site access for PGT145. Lee2017 (antibody binding site, structure)
3BNC117: Humanized mice were grafted with CD34+ T cells isolated from human umbilical cords, and later challenged by intra-rectal infection with HIV-1 strain NL4-3. Mice treated with a mix of 3 bNAbs (10-1074, 3BNC117, and SF12) resisted mucosal infection. Vanshylla2021 (neutralization, immunotherapy)
3BNC117: 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)
3BNC117: A novel CD4bs bNAb, 1-18, is identified with breadth (97% against a 119-strain multiclade panel) and potency (IC₅₀ = 0.048 µg/mL) exceeding 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. Variation 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)
3BNC117: 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. Castillo-Menendez2019 (vaccine antigen design, structure)
3BNC117: In an attempt to engage appropriate germline B cells that give rise to bNAbs, a combination of Env glycan modifications that permit far greater neutralization potency by near germline forms of multiple VRC01-class bNAbs were tested. The authors assessed CD4bs bNAbs for neutralizing activity against of Env-pseudotyped viruses (EPV) that were either Man5-enriched and/or had targeted glycan deletion and concluded that neutralization by germline-reverted forms of VRC01-class bNAbs requires a combination of both Man5-enrichment and glycan deletion. In particular, Man5-enrichment increased the sensitivity of 426c by 8–12 fold when assayed with mature VRC01, 3BNC117, VRC-CH31 and CH103, and this sensitivity increased further by targeted glycan deletion. Furthermore, Man5-enrichment increased the sensitivity of subtype C transmitted-founder 426c EPV that lacked glycan N276, and those that lacked two glycans at N460 and N463, to mature VRC01 by ˜10-fold. LaBranche2018 (antibody interactions, antibody lineage)
3BNC117: A dose-escalation phase 1b study in HIV-1-infected individuals to evaluate the safety, pharmacokinetics and antiretroviral activity of the combination of the Abs 3BNC117 and 10–1074 has been reported. Participants in groups 1A and 1B were virologically suppressed on ART and were randomized in a 2:1 ratio to receive one intravenous infusion of each of 3BNC117 and 10–1074 or placebo. Viremic individuals off ART were enrolled in group 1C or group 3, and received one intravenous infusion (group 1C) or three intravenous infusions (group 3, every two weeks) of each 3BNC117 and 10–1074. The combination of 3BNC117 and 10–1074 was more effective in suppressing viremia than either antibody alone. However, 3BNC117 and 10–1074 infusions failed to suppress viremia to undetectable levels in the two dual antibody-sensitive individuals with the highest pre-infusion viral load despite persistent reductions for up to 12 weeks. Bar-On2018 (neutralization, immunotherapy, HAART, ART)
3BNC117: 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. The G458Y signature mutation conferred complete resistance (IC50> 25 mg/mL) to 3BNC117 and can neutralize the CH505 TF (IC50 0.03 mg/mL). 3BNC117 has reduced breadth and potency against C clade viruses. Bricault2019 (antibody binding site, vaccine antigen design, computational epitope prediction, broad neutralizer)
3BNC117: 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 all 3 regimens were able to outcompete 3BNC117 binding to C97 gp140, suggesting that the sera contains antibodies that bind in the vicinity of CD4bs. Bricault2018 (antibody generation, vaccine-induced immune responses, polyclonal antibodies)
3BNC117: 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. 3BNC117 + CAP256-VRC26.25 was the most potent combination against subtype D. Wagh2018 (immunotherapy)
3BNC117: 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. 3BNC117 was used in analysis of monoclonal bNAb combinations. Hraber2018 (assay or method development, neutralization)
3BNC117: 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)
3BNC117: This review discusses the identification of super-Abs, where and how such Abs may be best applied and future directions for the field. 3BNC117 was isolated from human B cell clones and is functionally similar to VRC01. Both 3BNC117 and 3BNC117-LS are in Phase I clinical trials (Table 2). Antigenic region CD4 binding site (Table:1). Walker2018 (antibody binding site, review, broad neutralizer)
3BNC117: 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)
3BNC117: 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)
3BNC117: 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 3BNC117 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 (binding affinity, structure)
3BNC117: M428L and N434S mutations [referred to as “LS”] were introduced into the genes encoding the crystallizable fragment domains of 3BNC117 and 10-1074 bNAbs to increase their half-lives. The efficacy of modified bNAbs in blocking infections following repeated low dose mucosal challenges of rhesus macaques with the Tier 2 SHIVAD8-EO was evaluated. The most striking result was the long period of protective efficacy conferred by a single injection of crystallizable fragment domain-modified hbNAbs in macaques compared to that previously reported. A single intravenous infusion of the 10-1074-LS bNAb protected a cohort of 6 monkeys for up to 8.5 months (18 to 37 weeks). LS mutation in 10-1074 lengthened the median time until SHIVAD8-EO acquisition from 12.5 to 27 weeks, with 10-1074-LS bNAb measurable in the serum for 26 to 41 weeks and a calculated half-life of 3.8 weeks. The effects of the LS change on 3BNC117 were more modest than 10-1074, with a shorter half-life (2.6 versus 3.8 weeks), smaller increase in half-life (2 vs. 3.8-fold), and lower initial serum concentrations. Gautam2018 (immunoprophylaxis)
3BNC117: 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)
3BNC117: Early administration of bNAbs in a macaque-SHIV model is associated with a persistent very low level of viremia resulting in long-term infection control. Passive combination immunotherapy of 3BNC117 and 10-1074, 3 days after intrarectal infection, and targeting non-overlapping epitopes on the Env spike effected viremic suppression for 56-177 days, with rebound directly correlated to plasma concentration of bNAb. On day 56 macaque MVJ experienced SHIV_AD8-EO rebound when plasma 3BNC117 decayed below 1 µg/ml. Nishimura2017 (acute/early infection, immunotherapy)
3BNC117: 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)
3BNC117: 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)
3BNC117: 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 (immunotherapy)
3BNC117: 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)
3BNC117: Infusions of 3BNC117 were given to 13 HIV-infected individuals during analytical treatment interruption. The antibody was well tolerated. Infusions were associated with a delay in viral rebound. In most individuals, rebound viruses showed increased resistance to 3BNC117, but in 30% of patients the virus showed no sign of escape over a period of 9-19 weeks. Scheid2016 (escape, immunotherapy)
3BNC117: Chimeric antigen receptors, i.e., fusion proteins made from single-chain antibodies, may be a useful approach to immunotherapy. A set of mAbs were chosen based on their binding to a variety of sites on Env and availability of antibody sequences. The chimeric receptors were created by fusing the antibody's heavy chain, light chain, and two signaling domains into a single molecule. All 7 antibodies used to make the chimeric receptors (10E8, 3BNC117, PGT126, VRC01, X5, PGT128, PG9) showed specific killing of HIV-1 infected cells and suppression of viral replication against a panel of HIV-1 strains. Ali2016 (immunotherapy, chimeric antibody)
3BNC117: This review classified and mapped the binding regions of 32 bNAbs isolated 2010-2016. Wu2016 (review)
3BNC117: In neutralization assays of antibody mixtures, there was a modest synergy between the CD4bs VRC01 and either of the two CD4i MAbs E51 and 412d. The synergy is likely the result of the ability of CD4i antibodies (E51 or 412d) to induce the open state and facilitate access to the CD4 binding site. The presence of E51 enhanced the Env binding of VRC01, NIH45-46, NIH45-46^G54W, and to a lesser extent 3BNC117. Gardner2016 (antibody interactions)
3BNC117: 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)
3BNC117: 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)
3BNC117: 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 3BNC117 Fab and mouse Fc had improved or reduced in vivo activity depending on the Fc used. Bournazos2014 (neutralization, chimeric antibody)
3BNC117: 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 CD4bs binding bNAbs, 3BNC117 recognizes trimer similarly to CH103, CH106, 1NC9 and VRC01, and is inhibited by sCD4. It enhanced binding of several V1/V2-glycan, V3-glycan or outer domain (OD)-glycan bNAbs; and 3BNC117 binding is enhanced by Ab 8ANC195. OD-glycan bNAbs, PGT135 and PGT136, though ˜ 5x less efficient binders of trimer, were able to unidirectionally inhibit binding of 3BNC117, as also other CD4bs bNAbs, VRC01, 2BNC60, NIH45-46. 3BNC117, alongwith 1NC9 differs slightly from more typical CD4bs bNAbs by its dependence on N-276 glycan. Derking2015 (antibody interactions, neutralization, binding affinity, structure)
3BNC117: 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 2BNC117 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)
3BNC117: 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. 3BNC117 is a CD4bs-specific bnAb that has been administered in both primate and human trials. Stephenson2016 (immunotherapy, review)
3BNC117: This review discusses the breakthroughs in understanding of the biology of the transmitted virus, the structure and nature of its envelope trimer, vaccine-induced CD8 T cell control in primates, and host control of bnAb elicitation. Haynes2016 (review)
3BNC117: This review summarized the novel strategies for HIV vaccine discovery. Multiple therapeutic vaccines have failed in the past, in a non placebo controlled trial, a Tat vaccine demonstrated immune cell restoration, reduction of immune activation, and reduced HIV-1 DNA viral load. bNAbs offer both prevention potential and treatment. In early-phase clinical trials, VRC01 reduced viral load in HIV-1-infected individuals not on HAART. Gray2016 (vaccine antigen design, vaccine-induced immune responses, HAART, ART, review)
3BNC117: 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-CD4bs bNAb 3BNC117 was able to neutralize only 1/16 tested non-M primary isolates at an IC₅₀< 10µg/ml, RBF208,M/O at 0.63 µg/ml. Morgand2015 (neutralization, subtype comparisons)
3BNC117: 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. 3BNC117, a CD4bs bnAb belonged to a group with slopes >1. Webb2015 (neutralization)
3BNC117: 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. The overall charge on 3BNC117 is +5, average for VRC01-class antibodies. It requires the A61P substitution in mature bNAb for maximal neutralization, even though it thermally destabilizes the helix in that part of 3BNC117. Scharf2016 (structure)
3BNC117: 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)
3BNC117: Based on the results of 3BNC117 administered to human subjects, mathematical modeling was unable to recapitulate the kinetics of the viral decline. Revision of the model to fit the data suggested that the antibody may clear infected cells, in addition to neutralizing free virions. In in vitro experiments, 3BNC177, PG16, and 10-1074 were able to stain cells infected with HIV-1 YU2. Both 3BNC117 and 10-1074 recognized cells infected with primary virus isolates from human subjects that had been previously infused with 3BNC117. Either 3BNC117 alone, or in combination with 10-1074, was able to accelerate the clearance of YU2-infected cells in humanized mice, decreasing the half life of the infected cell. This result was shown to be mediated by the Fc-gamma receptor. Lu2016 (ADCC, immunotherapy)
3BNC117: A single infusion of 3BNC117 was administered to 27 HIV-1-infected individuals. Analysis of env sequences over time revealed significant increases in sequence diversity. Improved neutralizing responses to tier-2 viruses were seen in nearly all study subjects over a 6-month period, while untreated individuals showed little change. Viremic individuals receiving 3BNC117, however, produced Abs to autologous virus that were sensitive or resistant. It is unknown how passively-administered antibodies accelerate the emergence of bnAbs, but this appears to be the case. Schoofs2016 (immunotherapy)
3BNC117: Donor EB179 was a long-term non-progressor with high serum neutralization breadth and potency. 8 B-cell clones produced Abs, including 179NC75, which had the highest neutralization, especially to Clade B viruses, neutralizing 70% of a clade-B pseudovirus panel and 6 out of 9 cross-clade Env pseudoviruses as opposed to bNAb 3BNC117's neutralizing 7/9 of the same psuedoviral panel. Freund2015 (neutralization, broad neutralizer)
3BNC117: 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 3BNC117 had strong ADCC. Bruel2016 (ADCC, binding affinity)
3BNC117: 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 3BNC117 was the first to be tested in a human trial and has also shown promising results in studies in humanized mice and macaques. Halper-Stromberg2016 (immunotherapy, review)
3BNC117: 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 3BNC117 heavy and light chains and binding surfaces were reported (Table-S5). Wu2015 (structure, antibody lineage)
3BNC117: Four bNAbs (VRC01, VRC01-LS, 3BNC117, and 10-1074) were administered, singly or in combination, to macaques, followed by weekly challenges with clade B SHIV_AD8. In all cases, the administration of MAbs delayed virus acquisition. Control animals required 2 to 6 challenges before becoming infected, while animals receiving VRC01 required 4–12 challenges; 3BNC117 required 7–20 challenges; 10-1074 required 6–23 challenges; and VRC01-LS required 9–18 challenges. Animals that received a single antibody infusion resisted infection for up to 23 weekly challenges. Gautam2016 (immunotherapy)
3BNC117: 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. 3BNC117 was one of the antibodies in the VH gene restricted, 8ANC131-like class. Zhou2015 (neutralization, structure, antibody lineage, broad neutralizer)
3BNC117: 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)
3BNC117: 3BNC117 infusion in humans was well tolerated, demonstrated favorable pharmacokinetics, and reduced the viral load in HIV-1-infected individuals. Emergence of resistant viral strains was variable, with some individuals remaining sensitive to 3BNC117 for a period of 28 days, with significantly reduced viremia. Contact residues and several mutations in gp120 after immunotherapy are mentioned for different subjects, including G459D, Q363H, S461D and S274Y. Caskey2015 (immunotherapy)
3BNC117: This study reports the generation of a human CD4- and human CCR5-expressing transgenic luciferase reporter mouse that facilitates measurement of peritoneal and genitomucosal HIV-1 pseudovirus entry in vivo for the preclinical evaluation of prophylactic or vaccine candidates. The results showed that passive transfer of neutralizing Abs can protect HIV-LucTG mice from cervicovaginal infection with HIV-1 pseudoviruses. Gruell2013 (genital and mucosal immunity, immunotherapy)
3BNC117: 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)
3BNC117_dRU3: The 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. It is reported that glutamic acid to glutamine mutation at residue 96 decreased the binding affinity to 10 fold in this Ab. Zhou2013a (antibody sequence, structure, antibody lineage)
3BNC117: 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.) 3BNC117 was used to compare the heavy & light chain sequences as a template of VRC01 class Ab. Its crystal structure was studied. Zhu2013a (antibody sequence, structure)
3BNC117: 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. Cocktails including PGT121 were efficient, 3BNC117 alone resulted in only a transient small reduction of plasma viral loads. Barouch2013a (immunotherapy)
3BNC117: 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 3BNC117, against 181 diverse HIV-1 strains with available Ab-Ag complex structures. Chuang2013 (computational epitope prediction)
3BNC117: "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)
3BNC117: 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)
3BNC117: 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)
3BNC117: 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)
3BNC117: 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)
3BNC117: 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. 3BNC117, a CD4Bs Ab, was among the 17 bnAbs which were used in studying the mutations in FWR. Crystal structure of 3BNC117/gp120 was compared with 3BNC60 in the context of insertion mutations in FWR and its role in increasing neutralizing activities. Klein2013 (neutralization, structure, antibody lineage)
3BNC117: 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. 3BNC117 was studied as anti-CD4BS bnAbs belongs to VRC01 class. McGuire2013 (neutralization, antibody lineage)
3BNC117: 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. 3BNC117 has been referred as a PVL in discussing the breadth and potency of antiCD4 abs. West2012a (antibody lineage)
3BNC117: 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. Klein2012 (neutralization)
3BNC117: 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. 3BNC117 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)
3BNC117: Neutralization activity was compared against MAb 10E8 and other broad and potent neutralizers in a 181-isolate Env-pseudovirus panel. 2F5 neutralized 84% of viruses at IC₅₀ <50 μg/ml and 77% of viruses at IC₅₀ <1 μg/ml, compared with 98% and 72% of MAb 10E8, respectively. Huang2012a (neutralization)
3BNC117: 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. 3BNC117 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)
3BNC117: 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. 3BNC117 arises from IgVH1-2 and IgVK1D-33 germline genes and neutralized 100% of 118 isolates representing major HIV-1 clades, and 1/5 VRC01-resistant isolates, with IC₅₀ <50μg/ml. Only 17 of the viruses tested were more sensitive to VRC01 than to 3BNC117. NIH45-46, a new variant of VRC01, was more potent than VRC01 on 62 of the viruses tested but still less potent than 3BNC117. 3BNC117 was polyreactive - reacted with dsDNA and LPS, but not with ssDNA or insulin. Scheid2011 (antibody generation, neutralization, antibody sequence, broad neutralizer)

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Barouch2013a Dan H. Barouch, James B. Whitney, Brian Moldt, Florian Klein, Thiago Y. Oliveira, Jinyan Liu, Kathryn E. Stephenson, Hui-Wen Chang, Karthik Shekhar, Sanjana Gupta, Joseph P. Nkolola, Michael S. Seaman, Kaitlin M. Smith, Erica N. Borducchi, Crystal Cabral, Jeffrey Y. Smith, Stephen Blackmore, Srisowmya Sanisetty, James R. Perry, Matthew Beck, Mark G. Lewis, William Rinaldi, Arup K. Chakraborty, Pascal Poignard, Michel C. Nussenzweig, and Dennis R. Burton. Therapeutic Efficacy of Potent Neutralizing HIV-1-Specific Monoclonal Antibodies in SHIV-Infected Rhesus Monkeys. Nature, 503(7475):224-228, 14 Nov 2013. PubMed ID: 24172905. Show all entries for this paper.

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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.

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Bricault2018 Christine A. Bricault, James M. Kovacs, Alexander Badamchi-Zadeh, Krisha McKee, Jennifer L. Shields, Bronwyn M. Gunn, George H. Neubauer, Fadi Ghantous, Julia Jennings, Lindsey Gillis, James Perry, Joseph P. Nkolola, Galit Alter, Bing Chen, Kathryn E. Stephenson, Nicole Doria-Rose, John R. Mascola, Michael S. Seaman, and Dan H. Barouch. Neutralizing Antibody Responses following Long-Term Vaccination with HIV-1 Env gp140 in Guinea Pigs. J. Virol., 92(13), 1 Jul 2018. PubMed ID: 29643249. 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.

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.

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Caskey2015 Marina Caskey, Florian Klein, Julio C. C. Lorenzi, Michael S. Seaman, Anthony P. West, Jr., Noreen Buckley, Gisela Kremer, Lilian Nogueira, Malte Braunschweig, Johannes F. Scheid, Joshua A. Horwitz, Irina Shimeliovich, Sivan Ben-Avraham, Maggi Witmer-Pack, Martin Platten, Clara Lehmann, Leah A. Burke, Thomas Hawthorne, Robert J. Gorelick, Bruce D. Walker, Tibor Keler, Roy M. Gulick, Gerd Fätkenheuer, Sarah J. Schlesinger, and Michel C. Nussenzweig. Viraemia Suppressed in HIV-1-Infected Humans by Broadly Neutralizing Antibody 3BNC117. Nature, 522(7557):487-491, 25 Jun 2015. PubMed ID: 25855300. Show all entries for this paper.

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

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

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

Schoofs2016 Till Schoofs, Florian Klein, Malte Braunschweig, Edward F. Kreider, Anna Feldmann, Lilian Nogueira, Thiago Oliveira, Julio C. C. Lorenzi, Erica H. Parrish, Gerald H. Learn, Anthony P. West, Jr., Pamela J. Bjorkman, Sarah J. Schlesinger, Michael S. Seaman, Julie Czartoski, M. Juliana McElrath, Nico Pfeifer, Beatrice H. Hahn, Marina Caskey, and Michel C. Nussenzweig. HIV-1 Therapy with Monoclonal Antibody 3BNC117 Elicits Host Immune Responses against HIV-1. Science, 352(6288):997-1001, 20 May 2016. PubMed ID: 27199429. Show all entries for this paper.

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Vanshylla2021 Kanika Vanshylla, Kathrin Held, Tabea M Eser, Henning Gruell, Franziska Kleipass, Ricarda Stumpf, Kanika Jain, Daniela Weiland, Jan Münch, Berthold Grüttner, Christof Geldmacher, and Florian Klein. CD34T+ Humanized Mouse Model to Study Mucosal HIV-1 Transmission and Prevention. Vaccines, 9(3), 27 Feb 2021. PubMed ID: 33673566. Show all entries for this paper.

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

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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.

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

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

Pinto2019 Dora Pinto, Craig Fenwick, Christophe Caillat, Chiara Silacci, Serafima Guseva, Francois Dehez, Christophe Chipot, Sonia Barbieri, Andrea Minola, David Jarrossay, Georgia D. Tomaras, Xiaoying Shen, Agostino Riva, Maciej Tarkowski, Olivier Schwartz, Timothee Bruel, Jeremy Dufloo, Michael S. Seaman, David C. Montefiori, Antonio Lanzavecchia, Davide Corti, Giuseppe Pantaleo, and Winfried Weissenhorn. Structural Basis for Broad HIV-1 Neutralization by the MPER-Specific Human Broadly Neutralizing Antibody LN01. Cell Host Microbe, 26(5):623-637e8 doi, Nov 2019. PubMed ID: 31653484 Show all entries for this paper.

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

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

Displaying record number 2124

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

Notes

Showing 174 of 174 notes.

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

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

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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.

Chun2014 Tae-Wook Chun, Danielle Murray, Jesse S. Justement, Jana Blazkova, Claire W. Hallahan, Olivia Fankuchen, Kathleen Gittens, Erika Benko, Colin Kovacs, Susan Moir, and Anthony S. Fauci. Broadly Neutralizing Antibodies Suppress HIV in the Persistent Viral Reservoir. Proc. Natl. Acad. Sci. U.S.A., 111(36):13151-13156, 9 Sep 2014. PubMed ID: 25157148. Show all entries for this paper.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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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.

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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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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.

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

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.

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

Overbaugh2012 Julie Overbaugh and Lynn Morris. The Antibody Response against HIV-1. Cold Spring Harb. Perspect. Med., 2(1):a007039, Jan 2012. PubMed ID: 22315717. 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.

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.

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

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

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

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

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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.

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

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

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

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

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

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

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

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.

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.

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.

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

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

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

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.

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.

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

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

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

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

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

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

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

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

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

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

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

Wu2011 Xueling Wu, Tongqing Zhou, Jiang Zhu, Baoshan Zhang, Ivelin Georgiev, Charlene Wang, Xuejun Chen, Nancy S. Longo, Mark Louder, Krisha McKee, Sijy O'Dell, Stephen Perfetto, Stephen D. Schmidt, Wei Shi, Lan Wu, Yongping Yang, Zhi-Yong Yang, Zhongjia Yang, Zhenhai Zhang, Mattia Bonsignori, John A. Crump, Saidi H. Kapiga, Noel E. Sam, Barton F. Haynes, Melissa Simek, Dennis R. Burton, Wayne C. Koff, Nicole A. Doria-Rose, Mark Connors, NISC Comparative Sequencing Program, James C. Mullikin, Gary J. Nabel, Mario Roederer, Lawrence Shapiro, Peter D. Kwong, and John R. Mascola. Focused Evolution of HIV-1 Neutralizing Antibodies Revealed by Structures and Deep Sequencing. Science, 333(6049):1593-1602, 16 Sep 2011. PubMed ID: 21835983. Show all entries for this paper.

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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

Showing 71 of 71 notes.

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

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Displaying record number 2640

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

Notes

Showing 35 of 35 notes.

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

References

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Cai2018 Hui Cai, Rou-Shu Zhang, Jared Orwenyo, John Giddens, Qiang Yang, Celia C. LaBranche, David C. Montefiori, and Lai-Xi Wang. Synthetic HIV V3 Glycopeptide Immunogen Carrying a N334 N-Glycan Induces Glycan-Dependent Antibodies with Promiscuous Site Recognition. J. Med. Chem., 61(22):10116-10125, 21 Nov 2018. PubMed ID: 30384610. Show all entries for this paper.

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

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

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

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

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

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

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 2125

Download this epitope record as JSON.

MAb ID	PG16
HXB2 Location	Env	Env Epitope Map
Author Location	Env
Epitope
Subtype	A
Ab Type	gp120 V2 // V2 glycan(V2g) // V2 apex
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	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, contact residues, elite controllers, escape, genital and mucosal immunity, glycosylation, immunoprophylaxis, immunotherapy, 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 142 of 142 notes.

PG16: 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)
PG16: 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)
PG16: 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)
PG16: 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)
PG16: 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. PG16 broadly neutralized HIV-1AD8 full-length and cytoplasmic tail-deleted Envs Castillo-Menendez2019 (vaccine antigen design, structure)
PG16: 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)
PG16: 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)
PG16: 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)
PG16: 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)
PG16: 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. V2 bNAb PG16 bound Opt and Alt immunogens more robustly than 459C WT, consistent with increased V2 exposure. Bricault2019 (antibody binding site, vaccine antigen design, computational epitope prediction, broad neutralizer)
PG16: This review discusses the identification of super-Abs, where and how such Abs may be best applied, and future directions for the field. Recombinant native-like HIV Env trimers have enabled the identification of PG16, a potent ‘PG9-class’ bNAb. Antigenic region V2 apex (Table:1) Walker2018 (antibody binding site, review, broad neutralizer)
PG16: 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)
PG16: 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)
PG16: 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)
PG16: 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 PG16 in ELISA EC50 and Surface Plasmon Resonance (SPR) assays. Wen2018 (glycosylation, vaccine antigen design)
PG16: 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
PG16: Assays of poly- and autoreactivity demonstrated that broadly neutralizing NAbs are significantly more poly- and autoreactive than non-neutralizing NAbs. PG16 is neither autoreactive nor polyreactive. Liu2015a (autoantibody or autoimmunity, antibody polyreactivity)
PG16: 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)
PG16: 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 PG16, as it doesn't bind to WT 89.6 or JRFL. Hogan2018
PG16: 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)
PG16: 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)
PG16: 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)
-PG16: 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. Consistent competition of PG16 was seen with some rabbit sear. Crooks2015 (glycosylation, neutralization)
PG16: 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)
PG16: Somatic hypermutation and affinity maturation improve an antibody's complementarity with its target epitope. Mass spectroscopy and X-ray structures were used to examine two classes of mAbs, CD4 binding Abs (VRC03, VRC-PG04) and V2 binding Abs (VRC26.01, VRC26.03, VRC26.10, PG16, CH03), to determine how specific mutations that occurred during maturation affected the binding of the mAbs to their target epitope. Davenport2016 (structure, antibody lineage)
PG16: 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. PG16 had weak to moderate ADCC activity on cells infected with 2 of the 3 strains studied. vonBredow2016 (ADCC)
PG16: 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)
PG16: 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-V1/2 PG16 Fab and mouse Fc had improved or reduced in vivo activity depending on the Fc used. Bournazos2014 (neutralization, chimeric antibody)
PG16: 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)
PG16: 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 PG16 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)
PG16: 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)
PG16: 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, PG16, neutralized B41 psuedovirus and bound B41 trimer strongly. Pugach2015
PG16: 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. PG16, PG9 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 PG16 strongly, but in a non-reciprocal manner. Derking2015 (antibody interactions, neutralization, binding affinity, structure)
PG16: 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 reactive with the V1/V2 glycan bNAb, PG16, and both pseudotyped viruses were neutralized by PG167. Julien2015 (assay or method development, structure)
PG16: 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 PG16 to trimers was minimally affected by trimer cross-linking. Schiffner2016 (assay or method development, binding affinity, structure)
PG16: 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 7 fold sensitivity to bNAb PG16. vandenKerkhof2016 (elite controllers, neutralization, escape)
PG16: 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 PG16, 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)
PG16: 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 PG16 was assayed against JRFL (resistant strain) and JRFL-FLE168KN189A (sensitive strain). Magnus2016 (neutralization, escape)
PG16: 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. PG16 was compared to the newly-derived mAbs; it had no significant cross-reactivity with gut bacteria and tested negative in 2 tests of autoreactivity. Jeffries2016 (antibody polyreactivity)
PG16: 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, PG16, bound trimer best, but less well to protomer. Yasmeen2014 (antibody binding site, assay or method development)
PG16: 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, PG16 when compared had a geometric mean of IC₅₀=0.24 µg/ml for 11/12 viruses it neutralized at a potency of 92%. 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)
PG16: 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 PG16 was able to neutralize 4/16 tested non-M primary isolates at an IC₅₀< 10µg/ml, 1 of them highly with a value under 1 µg/ml and 3 moderately. Morgand2015 (neutralization, subtype comparisons)
PG16: 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. PG16, a V2-glycan bnAb belonged to a group with slopes <1. Webb2015 (neutralization)
PG16: 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-PG16 precursor bound to 1/3 trimers, BG505. Sliepen2015 (binding affinity, antibody lineage)
PG16: 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 PG16 had weak ADCC. Bruel2016 (binding affinity)
PG16: 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 PG16 has been associated with viral suppression in humanized mice. Halper-Stromberg2016 (immunotherapy, review)
PG16: 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)
PG16: 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)
PG16: 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 PG16 have affinity for epitopes located in the conserved regions of the V2-V3 loop. Binding of PG16 with the virus was largely dependent on the same residues and 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)
PG16: 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)
PG16: 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. PG 16 did bind to the monomeric V1V2 scaffolds. Gorman2016 (glycosylation, structure, antibody lineage)
PG16: 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. PG16 was active against T/F viruses' transmission. Malbec2013
PG16: 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 PG16 was used to understand the binding specificity and showed detectable binding only to an α-2,6-linked sialic acid terminated complex type oligosaccharides, implying significant structural specificity. Shivatare2013 (glycosylation, structure)
PG16: 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)
PG16: 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)
PG16: 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. Gavrilyuk2013 (neutralization)
PG16: 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 PG16 against the V1V2 domain. Bontjer2013 (vaccine antigen design, structure)
PG16: 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)
PG16: 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)
PG16: 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)
PG16: 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)
PG16: 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)
PG16: PG16 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 0/5 chronic Envs, 0/6 Consensus Envs and 1/7 T/F Envs. Liao2013c (antibody interactions, binding affinity)
PG16: 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 PG16 showed significantly high IVCI of 11.6 and captured all the 4 strains tested. Liu2014 (binding affinity)
PG16: 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)
PG16: 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. PG16 didn't bind to the immunogens in any form and none of the parental Env were neutralized. Carbonetti2014 (elite controllers, vaccine-induced immune responses)
PG16: This study examined how the conserved gp120-gp41 association site adapts to glycan changes that are linked to neutralization sensitivity, using a DSR mutant virus, K601D. K601D has a defective gp120-association, and was sequentially passaged in peripheral blood mononuclear cells to select for suppressor mutations. Mutations 136 and/or glycan 142 increased the sensitivity of only ΔN. Drummer2013 (antibody interactions, glycosylation)
PG16: 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. PG16 showed very high neutralization titer against BG505 pseudovirus in a competitive binding assay as shown in Table 1. Adsorption of gp120 protein to alum resulted in loss of binding to PG16, but not to PG9. Hoffenberg2013 (antibody interactions, glycosylation, neutralization)
PG16: 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. PG16 neutralized 72% of a cross-clade panel of 157 HIV-1 isolates (Fig. S1) while 1F7 neutralized only 20% of the isolates. Gach2013 (neutralization)
PG16: 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. PG16 was used in CD4 coexpression and competitive binding assay. Veillette2014 (ADCC)
PG16: 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. PG16 was used as a V2 prototype bnAb control. Falkowska2014
PG16: 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)
PG16: 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
PG16: This is a review of a satellite symposium at the AIDS Vaccine 2012 conference, focusing on antibody gene transfer. Michel Nussenzweig presented studies exploring the possibility that antibodies might also be used to treat established infections. They found that combinations of five broadly neutralizing antibodies NIH45-46G54W, PG16, PGT128, 10-1074 and 3BC176 MAbs, controlled HIV-1 infection and suppressed the viral load to below the limit of detection during the entire therapy period of up to 60 days. Balazs2013 (immunoprophylaxis, immunotherapy)
PG16: 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 PG16, against 181 diverse HIV-1 strains with available Ab-Ag complex structures. Chuang2013 (computational epitope prediction)
PG16: 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)
PG16: 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. PG16 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. Liao2013b (ADCC)
PG16: "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)
PG16: 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. PG16 was used as the positive control in different assays. Guan2013 (ADCC, antibody interactions)
PG16: 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. PG16 was used to asses Env solubilization and purification approach affecting the integrity of the binding epitope. Mao2012 (structure)
PG16: Previous study (Liu2011) showed that glycosylphosphatidylinositol (GPI)-anchored HCDR3 subdomains (GPI-HCDR3) can be targeted to lipid rafts of the plasma membrane, bind to the epitope recognized by HCDR3 of PG16, and neutralize diverse HIV-1 isolates. This study further developed trimeric GPI-HCDR3s and demonstrated that trimeric GPI-HCDR3 (PG16) dramatically improves anti-HIV-1 neutralization, suggesting that a stoichiometry of recognition of 3 or 2 HCDR3 molecules (PG16) to 1 viral spike is possible. Liu2013 (neutralization, antibody sequence, structure)
PG16: 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). PG16 neutralized 44% of these viruses. Goo2012 (neutralization, rate of progression)
PG16: 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)
PG16: 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)
PG16: 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)
PG16: 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. PG16, which recognizes V1/V2 loop, was among the 17 bnAbs which were used in studying the mutations in FWR. Fig S4C described the comparison of Ab framework amino acid replacement vs. interactive surface area on PG16. Klein2013 (neutralization, structure, antibody lineage)
PG16: 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)
PG16: 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 PG16 Pejchal2011 (glycosylation, structure, broad neutralizer)
PG16: 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. PG16 was used as a trimer specific control antibody in binding and neutralization assay. Haim2011 (antibody interactions)
PG16: 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)
PG16: 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. PG16 was used as BnAb to screen Env clones. wtR clone was resistant to PG16. ORourke2012 (neutralization)
PG16: 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. PG16 was referred to have second BCN Ab epitopes at AA 156 and 160 in addition to 332. Moore2012 (neutralization, escape)
PG16: 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. PG16 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)
PG16: The use of computationally derived B cell clonal lineages as templates for HIV-1 immunogen design is discussed. PG16 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)
PG16: Polyclonal B cell responses to conserved neutralization epitopes are reported. Cross-reactive plasma samples were identified and evaluated from 308 subjects tested. PG16 was used as a control mAb in the comprehensive set of assays performed. PG9 was used as a control 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)
PG16: HIV therapy by combinations of 5 bNAbs was tested in YU2-infected humanized mice. Penta-mix (PG16, 45-46W, 3BC176, PGT128 and 10-1074) was the most effective in controlling the viraemia compared to tri-mix (PG16, 45-46, 3BC176) and monotherapy (Fig S9). Viral escape with PG16 monotherapy was associated with mutations at residues 160 and 162 at potential N-linked glycosylation site in V1/V2 loop. The viruses from the mice that rebounded after tri-mix therapy either did not have bNAbs-associated mutations or had K28R mapped to NIH45-46W or N162P mapped to PG16, but not both. Klein2012a (escape, immunotherapy)
PG16: 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. PG16 was used as a control in neutralizing assay. Klein2012 (neutralization)
PG16: 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. PG16 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)
PG16: 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. PG16 has been referred in discussing the efficiency of YU-2 gp140 trimer as a bait for Ab capture. Mouquet2011 (neutralization)
PG16: 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. PG16 has been discussed regarding the sites of HIV-1 vulnerability to neutralizing antibodies and in terms of humoral immune response during HIV1 infection. Kwong2011 (antibody binding site, neutralization, vaccine antigen design, review)
PG16: 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. PG16 was used as a control to compare the neutralizing activity of patients' sera. Lavine2012 (neutralization)
PG16: 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. PG16 is discussed in the context of developing broadly cross-neutralizing antibodies. Overbaugh2012 (escape, review)
PG16: Neutralization activity was compared against MAb 10E8 and other broad and potent neutralizers in a 181-isolate Env-pseudovirus panel. 2F5 neutralized 73% of viruses at IC50<50 μg/ml and 59% of viruses at IC50<1 μg/ml, compared with 98% and 72% of MAb 10E8, respectively. Huang2012a (neutralization)
PG16: 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 PG16 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)
PG16: 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)
PG16: 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)
PG16: 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 PG16 in 10 Env-pseudotyped viruses was analyzed. Five clones from case 0377 presented a broad and continuous range of sensitivity to PG16. A broader range of sensitivity was observed in case 0978, clone 0978-M3 being resistant to PG16 whereas two other clones, 0978-M1 and 0978-M2, were highly sensitive. Clone 0858-M1 was resistant to PG16 whereas clone 0858-M2 was resistant to PG16. These results showed the broad heterogeneity in sensitivity to PG16 of closely genetically related envelope glycoproteins derived from single viral quasispecies. Clone 0978-M3 from case 0978 was resistant to PG16, whereas clones 0978-M1/M2 were highly sensitive to PG16. 0978-M3 E168K resulted in a high sensitivity to both PG16. In contrast, 0978-M2 K168E conferred resistance to PG16. I215M diminished the sensitivity of all clones to PG16. Thenin2012a (neutralization)
PG16: 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. For PG16, 3 of the 7 viruses (Lai/Balenv, Lai, and 89.6) demonstrated <50% inhibition at the highest tested concentration. For JRCSF, YU-2, and NL4-3, the PG16 IC50 was not significantly different between infections initiated with cell-free virus and those initiated with mDC-associated virus. 4E10 and 2F5 bound a significantly greater percentage of mDCs, compared with PG16. Sagar2012 (neutralization, binding affinity)
PG16: 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)
PG16: 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)
PG16: 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)
PG16: Crystal structure of the antigen-binding fragment (Fab) of 2909 at a 3.3-Å resolution was determined and compared to the previously determined structure of PG16. Comparison of 2909 to PG16 showed that both utilize protruding, anionic CDR H3s for recognition. Both 2909 and PG16 are highly dependent on the residue at position 160 in the V2 loop and the primary reason 2909 does not neutralize as broadly as PG16 was suggested to relate specifically to the N160K substitution, thereby suggesting that 2909 and PG16 recognize different immunotypes of the same epitope. Changela2011 (antibody binding site, structure)
PG16: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)
PG16: 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, PG16 neutralized 21 strains in IgG form, 15 stains in Fab form, 17 strains in IA form and 27 strains in VRC01_scFv-PG16 form. It was found that the PG9, PG16, and VRC01 IAs were severalfold less potent than their IgG forms. West2012 (neutralization)
PG16: 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)
PG16: 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)
PG16: 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 PG16 of T/F Envs compared to chronic Envs. Wilen2011 (neutralization)
PG16: 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. PG16 showed the broadest activity, neutralizing 57% of contemporary viruses at IC50 < 1 μ g/ml. Viruses from contemporary seroconverters were significantly more resistant to neutralization by VRC01 and tended to be more resistant to neutralization by PG16. Despite that, all recently transmitted viruses were sensitive to at least one broadly neutralizing Ab at concentration < 5 μg/ml. There was no clear correlation between the sensitivity to PG16 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 PG16. Euler2011 (glycosylation, neutralization, escape)
PG16: PG16 paratope was mapped by assessing neutralization with arginine mutants. The resultant ‘arginine-scanning’ mutagenesis revealed a close match to the observed V1/V2 interface for PG9. The binding of PG9 and PG16 to monomeric gp120 in wild-type and V3-deleted contexts showed similar affinities, indicating that—in the context of monomeric gp120—V3 does not have a substantial role in PG9 or PG16 recognition and V1/V2 in the viral spike both shields and interacts with V3. All five 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 (antibody binding site, structure)
PG16: 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. CDR H3 subdomain of PG16 neutralized HIV-1 when targeted to the lipid raft of the plasma membrane of HIV-1 -susceptible cells. GPI-CDR H3(PG16) reduced the infection of 17 HIV-1 pseudotypes by over 99%, inhibited the infection of the other 6 HIV-1 pseudotypes by over 90%, and reduced the infection of JRFL by 70%. CDR H3 mutations (Y100HF, D100IA, and G7) abolished the neutralization activity of GPI-CDR H3(PG16). Liu2011 (neutralization, variant cross-reactivity, structure)
PG16: 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 PG16 over 4–2.J45 expressing I424, wherein comparable sensitivities were found of other Envs to PG16 except YU2, which showed approximately 3 fold increase in neutralization sensitivity to PG16. 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)
PG16: 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 PG16 epitope on the gp120 subunit and the trimerization of soluble gp140 may lead to the partial occlusion of the PG16 epitope. PG16 most efficiently recognized modified SF162 Env, SF162K160N of the small number of soluble gp140 Envs tested. The absence of SF162 neutralization by PG16 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)
PG16: 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)
PG16: 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)
PG16: 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)
PG16: 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. Walker2010a (neutralization, review)
PG16: 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. PG16 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. PG16 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)
PG16: 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)
PG16: 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)
PG16: Unlike the MPER MAbs tested, PG16 did not show any Env-independent virus capture in the conventional or in the modified version of the virus capture assay. Leaman2010
PG16: 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)
PG16: 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)
PG16: Novel techniques for generation of broadly neutralizing Abs and how these Ab can aid in development of an effective vaccine are discussed. Joyce2010 (review)
PG16: 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)
PG16: 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)
PG16: PG16 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)
PG16: 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)
PG16: Removal of N-linked glycosylation sites was shown to generally lead to a reduction in neutralization sensitivity to PG16, 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 PG16. Binding of PG16 to Env transfected cells was not competed by monosaccharides indicating that PG16 sensitivity to glycosylation was due to the effect of glycans on gp120 conformation and PG16 epitope accessibility. Doores2010 (antibody binding site, glycosylation, neutralization, binding affinity)
PG16: Crystal structure of PG16 Fab was determined. The CDR H3 region was 28 residues long resembling an axe, and extending above the Ab variable domains as a semi-independent subdomain. This region was shown critical for neutralization activity of the Ab. Affinity maturation of PG16 correlated with Ab neutralization breadth, as light chain V-gene reversion produced chimeric Abs with less neutralization. PG16 had a single N-linked glycan that extended off the side of the light chain variable domain, but was not required for neutralization. Fab and IgG formats of PG16 had comparable neutralization potencies. The likely site of PG16 reaction with Env was determined to consist of CDR L1 and L2 and the CDR H3 elements. Pancera2010 (glycosylation, neutralization, structure)
PG16: Broadly neutralizing sera from elite neutralizers exhibited significant sensitivities to mutations I165A, N332A, and N160K. PG16 neutralization activity was tested for pseudoviruses with the mutations relative to the WT. PG16 was shown to require N160K glycosylation for potent neutralizing activity. Pseudoviruses produced in cells treated with kifunensine were found resistant to PG16 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)
PG16: Crystal structure of PG16 Fab fragment was determined. PG16 was shown to have a 28-residue 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 PG16 neutralization. CDR H3 tyrosine for PG16 was singly sulfated, and tyrosine sulfation was shown to play a role in both binding and neutralization. Glycosylation of PG16 light chain did not have a significant effect on neutralization. Pejchal2010 (glycosylation, neutralization, binding affinity, structure)
PG16: This MAb was derived from clade A infected patient. PG16 failed to bind to recombinant gp120 or gp41 but exhibited high neutralization breadth and potency, neutralizing 119 out of 162 cross-clade viruses with a potency exceeding that of b12, 2G12, and 2F5. PG16 also potently neutralized IAVI-C18 virus, that is neutralization resistant to all four bNAbs. PG16 preferred binding to trimeric Env due to subunit presentation in this form. Residues that form the epitope for PG16 were primarily located in the conserved regions of the V2 and V3 loops. N-glycosylation sites N156 and N160 in the V2 region were critical in forming the PG16 epitope. This Ab had a long CDRH3 loop. Walker2009a (antibody generation, glycosylation, neutralization, variant cross-reactivity, binding affinity)

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Displaying record number 2163

Download this epitope record as JSON.

MAb ID	VRC01 (VRC01_d45, VRC-HIVMAB060-00-AB)
HXB2 Location	Env	Env Epitope Map
Author Location	gp120
Epitope	(Discontinuous epitope)
Subtype	B
Ab Type	gp120 CD4BS
Neutralizing	tier 2 View neutralization details
Contacts and Features	View contacts and features
Species (Isotype)	human(IgG1)
Patient	NIH45
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, bispecific/trispecific, broad neutralizer, CD4+ CTL, chimeric antibody, computational epitope prediction, contact residues, dynamics, elite controllers, enhancing activity, escape, genital and mucosal immunity, germline, glycosylation, HAART, ART, HIV reservoir/latency/provirus, HIV-2, immunoprophylaxis, immunotherapy, junction or fusion peptide, kinetics, memory cells, mother-to-infant transmission, neutralization, novel epitope, polyclonal antibodies, rate of progression, review, structure, subtype comparisons, therapeutic vaccine, vaccine antigen design, vaccine-induced immune responses, variant cross-reactivity, viral fitness and reversion

Notes

Showing 222 of 222 notes.

VRC01: 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. VRC01-Env formed a distinct group within the CD4bs category, Class VRC01. Crystal structure data at 3.4A resolution of fully glycosylated Clade G X1193.ct SOSIP.664 prefusion trimer with VRC01 as well as PGT122 and 35O22 was found in PDB ID: 5FYJ. Chuang2019 (antibody binding site, antibody interactions, binding affinity, antibody sequence, structure, antibody lineage, broad neutralizer)
VRC01: 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)
VRC01: 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)
VRC01: 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. Previously-published neutralization data for VRC01 and VRC01-LS were used for comparison purposes. Zhang2022 (neutralization, immunotherapy, broad neutralizer)
VRC01: 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)
VRC01: 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)
VRC01: 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)
VRC01: 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)
VRC01: 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)
VRC01: 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. In BG505.Env.C2 alanine-scanning neutralization assays, VRC01 had more similar results to hammerhead-class antibodies PG9 & CH01 than to PGT145-like antibodies. Lee2017 (antibody binding site, neutralization)
VRC01: 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)
VRC01: 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)
VRC01: 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. VRC01 broadly neutralized HIV-1AD8 full-length and cytoplasmic tail-deleted Envs. Castillo-Menendez2019 (vaccine antigen design, structure)
VRC01: In an attempt to engage appropriate germline B cells that give rise to bNAbs, a combination of Env glycan modifications that permit far greater neutralization potency by near germline forms of multiple VRC01-class bNAbs were tested. The authors assessed CD4bs bNAbs for neutralizing activity against of Env-pseudotyped viruses (EPV) that were either Man5-enrichment and/or had targeted glycan deletion and concluded that neutralization by germline-reverted forms of VRC01-class bNAbs requires a combination of both Man5-enrichment and glycan deletion. In particular, Man5-enrichment increased the sensitivity of 426c by 8–12 fold when assayed with mature VRC01, 3BNC117, VRC-CH31 and CH103, and this sensitivity increased further by targeted glycan deletion. Furthermore, Man5-enrichment increased the sensitivity of subtype C transmitted-founder 426c EPV that lacked glycan N276, and those that lacked two glycans at N460 and N463, to mature VRC01 by ˜10-fold. LaBranche2018 (antibody interactions, antibody lineage)
VRC01: Expanding on previous work aimed at understanding the germline VRC01-class antibody-recognition potential of the previously described 426c Env, the authors characterize the crystal structure, binding and contacts to the germline VRC01 of two C Env constructs: the previously described soluble trimeric 426c SOSIP with three NLGSs removed at positions Asn276, Asn460, and Asn463; and a monomeric 426c core containing all wild-type NLGSs (including those at positions Asn276, Asn460, and Asn463), but lacking variable loops 1, 2, and 3. The authors test and characterize various glycan-deleted combinations and NLGS backbones and demonstrate that germline VRC01 could bind to a 426c core construct in the presence of all naturally occurring NLGSs surrounding the CD4BS, including the NLGS at position Asn276 and with its associated glycan. Borst2018 (antibody interactions, antibody lineage)
VRC01: 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)
VRC01: 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)
VRC01: To reduce local V2 flexibility and improve the binding of V2-dependent bNAbs and germline precursor bNAbs, the authors designed BG505 SOSIP.664 trimer variants whose V1 and V2 domains were stabilized by introducing disulfide bonds either within the V2 loop or between the V1 and V2 loops. The resulting SOSIP trimer variants — E153C/K178C, E153C/K178C/G152E and I184C/E190C — have improved reactivity with V2 bNAbs and their inferred germline precursors and are more sensitive to neutralization by V2 bNAbs. Compared with BG505 SOSIP.664, the E153C/R178C V1-V2 disulfide mutant bound the VRC01, PGT151, and 2G12 slightly less well and the G152E compensatory mutation improved VRC01, PGT151, and 2G12 binding. However, there was no change in sensitivity to VRC01 for either mutant virus E153C/K178C/G152E and I184C/E190C. deTaeye2019 (antibody interactions, variant cross-reactivity, binding affinity, structure, broad neutralizer)
VRC01: 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)
VRC01: The authors used nuclear magnetic resonance (NMR) to define the structure of the HIV-1 MPER when linked to the transmembrane domain (MPER-TMD) in the context of a lipid bilayer. In particular, they looked at the accessibility of the MPER-TMD to 2F5, 4E10, 10E8 and DH570. The MPER appears to be accessible up to ∼10% of the time to the 2F5, 4E10, and 10E8 Fabs but ∼40% of time to the DH570 Fab. To assess possible functional roles for the MPER in membrane fusion, they generated 17 Env mutants using the sequence of a clade A isolate, 92UG037.8, mutating each of the three structural elements: hydrophobic core, turn, and kink. Mutants W670A (hydrophobic core), F673A (turn), and W680A (kink), while still sensitive to VRC01, became much more resistant to the trimer-specific bNAbs and also gained sensitivity to b6, 3791, and 17b. All mutants with changes at W666 in the hydrophobic core and K683 at the kink lost infectivity almost completely. For the rest of the mutants, infectivity ranged from 4.3 to 50.8% of that of the wild type, showing that key residues important for stabilizing the MPER structure are also critical for Env-induced membrane fusion activity, especially in the context of viral infection. Fu2018 (antibody binding site, antibody interactions, neutralization, variant cross-reactivity, binding affinity, structure)
VRC01: 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)
VRC01: 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. The G458Y signature mutation conferred complete resistance (IC50 > 25 mg/mL) to VRC01 and can neutralize the CH505 TF (IC50 of 0.14mg/mL).VRC01 have reduced breadth and potency against C clade viruses. Bricault2019 (antibody binding site, vaccine antigen design, computational epitope prediction, broad neutralizer)
VRC01: 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)
VRC01: 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)
VRC01: 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)
VRC01: VRC 606 (clinicaltrials.gov NCT02599896) was a single-site Phase I open-label dose-escalation study that evaluated a variant of VRC01, VRC01LS for safety and pharmacokinetic (PK) parameters. VRC01LS has mutations M428L and N434S in the Fc region intended to extend serum half-life, these LS mutations result in enhanced IgG-FcRn binding but do not affect binding to the Fc-gamma receptor and thus do not impair Fc-mediated effector functions, such as antibody dependent cellular cytotoxicity (ADCC). It was observed that VRC01LS was safe and well tolerated and displayed a serum half-life more than four times longer than wild-type VRC01. The VRC01LS Ab retained its neutralizing activity in serum for the 48-week duration of this study, and no Abs were detected to it. Gaudinski2018 (enhancing activity, therapeutic vaccine, immunotherapy, broad neutralizer)
VRC01: This review discusses the identification of super-Abs, where and how such Abs may be best applied, and future directions for the field. VRC01, a prototype super-Ab, was isolated from direct functional screening of thousands of B cell clones. VRC01 is in Phase I clinical development and the Antibody-Mediated Prevention (AMP) study will assess the ability of the VRC01 mAb specific for CD4 binding site to decrease the risk of HIV acquisition in humans. Walker2018 (antibody binding site, review, broad neutralizer)
VRC01: 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)
VRC01: 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)
VRC01: 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)
VRC01: 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)
VRC01: 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)
VRC01: 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)
VRC01: 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 VRC01 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)
VRC01: 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 bound to VRC01 in ELISA EC50 and Surface Plasmon Resonance (SPR) assays. 6240.B gp120 bound to VRC01. 6240.B gp120 exhibited binding to VRC01. Wen2018 (glycosylation, vaccine antigen design)
VRC01: 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
VRC01: Prevention of HIV infection by intravenously-administered VRC01 was modeled to predict prevention efficacy (PE) of each 10 mg/kg or 30 mg/kg VRC01 dose. Nonhuman primates (NHPs) were administered high-dose intra-rectal simian-human immunodeficiency virus challenge two days post-VRC01 infusion (“NHP model”). As humans may require greater VRC01 concentration to achieve the same level of protection, it was assumed that 5-fold greater VRC01 serum concentration would be needed to provide the same level of per-exposure PE as seen in the NHP data (“5-fold model”). For the 10 mg/kg regimen, the 5-fold and NHP models predict an overall PE of 37% and 64%, respectively; for the 30 mg/kg regimen, the two models predict an overall PE of 53% and 82%, respectively. Huang2018 (immunoprophylaxis)
VRC01: Assays of poly- and autoreactivity demonstrated that broadly neutralizing NAbs are significantly more poly- and autoreactive than non-neutralizing NAbs. VRC01 is autoreactive, but not polyreactive. Liu2015a (autoantibody or autoimmunity, antibody polyreactivity)
VRC01: This study was designed to evaluate the safety, pharmacological profile, and immune functions of VRC01 administered either subcutaneously or intravenously as a foundation for future efficacy trials. HIV Vaccine Trials Network (HVTN) 104 was designed to evaluate the safety and tolerability of multiple doses of VRC01. Eighty-eight healthy, HIV-uninfected, low-risk participants were enrolled in 6 United States clinical research sites affiliated with the HVTN between September 9, 2014 and July 15, 2015. Participants were randomized to receive the following: a 40 mg/kg IV VRC01 loading dose followed by five 20 mg/kg IV VRC01 doses every 4 weeks (treatment group 1 [T1], n = 20); eleven 5 mg/kg subcutaneous (SC) VRC01 (treatment group 3 [T3], n = 20); placebo (placebo group 3 [P3], n = 4)doses every 2 weeks; or three 40 mg/kg IV VRC01 doses every 8 weeks (treatment group 2 [T2], n = 20). Treatment groups T4 and T5 (n = 12 each) received three 10 or 30 mg/kg IV VRC01 doses every 8 weeks, respectively. Participants were followed for 32 weeks after their first VRC01 administration and received a total of 249 IV infusions and 208 SC injections, with no serious adverse events, dose-limiting toxicities, nor evidence for anti-VRC01 antibodies observed. The limitations of this study include the relatively small sample size of each VRC01 administration regimen and missing data from participants who were unable to complete all study visits. The antibody in serum after administration showed evidence of a number of immune functions that are known to inhibit HIV transmission and replication. Mayer2017 (immunoprophylaxis, immunotherapy)
VRC01: 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)
VRC01: This study reports host tolerance mechanisms that limit the development of CD4bs and HCDR3-binder bNAbs via sequential HIV-1 Env vaccination. Vaccine-induced macaque CD4bs bnAbs recognize open Env trimers, and accumulate relatively modest somatic mutations. In naive CD4bs, unmutated common ancestor knock-in mice Env + B cell clones develop anergy and partial deletion at the transitional to mature B cell stage, but become Env- upon receptor editing. Stepwise immunization initiates CD4bs-bnAb responses, but immune tolerance mechanisms restrict their development. Crystal structure of DH522 showed footprints of VRC01 and CD4 attachment inhibitor N-(4-bromophenyl)-N′-(2,2,6,6-tetramethylpiperidin-4-yl)ethanediamide (NBD-557). Williams2017a (glycosylation, structure, antibody lineage, chimeric antibody)
VRC01: 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 VRC01. Hogan2018 (vaccine antigen design)
VRC01: The HIV Vaccine Trials Network and the HIV Prevention Trials Network conducted the first clinical test-of-concept, Antibody Mediated Prevention (AMP) trials to assess whether, and how, intravenous infusion of VRC01, prevents HIV-1 infection. HIV-1 prevention efficacy trials were conducted in two cohorts: 2700 HIV-uninfected men and transgender persons who have sex with men in the United States, Peru, Brazil, and Switzerland; and 1500 HIV-uninfected sexually active women in seven countries in sub-Saharan Africa. Participants were randomized 1:1:1 to receive an intravenous infusion of 10 mg/kg VRC01, 30 mg/kg VRC01, or a control preparation every 8 weeks for a total of 10 infusions. Each trial wasdesigned (1) to assess overall prevention efficacy (PE) pooled over the two VRC01 dose groups vs. control and (2) to assess VRC01 dose and laboratory markers as correlates of protection (CoPs) against overall and genotype- and phenotype-specific infection. Each AMP trial was designed to have 90% power to detect PE > 0% if PE is ≥ 60%. If affirmative, they will provide information for estimating the optimal dosage of VRC01 (or subsequent derivatives) and identify threshold levels of neutralization and Fc effector functions associated with high-level protection. Gilbert2017 (immunoprophylaxis)
VRC01: 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 VRC01. deTaeye2018 (broad neutralizer)
VRC01: 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-CD4bs NAb VRC01, had a Kd of 14.6 nM and bound the Env-ND well. Witt2017 (vaccine antigen design, binding affinity)
VRC01: 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. In a binding assay, VRC01 binding was reduced by mutants of CRF01_AE Env protein A244. Easterhoff2017 (binding affinity)
VRC01: 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. VRC01 recognizes this trimer. Chuang2017 (antibody interactions)
VRC01: 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)
VRC01: 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)
VRC01: 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)
VRC01: 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)
VRC01: Mice twice-primed with DNA plasmids encoding HIV-1 gp120 and gag and given a double boost with HIV-1 virus-like particles (VLPs) i.e. DDVV immunization, elicited Env-specific antibody responses as well as Env- and Gag-specific CTL responses. In vivo electroporation (EP) was used to increase breadth and potency of response. Human anti-gp120 VRC01 was used to prove that the VLP spike included the broad neutralization epitope recognized by it. Huang2017a (therapeutic vaccine, variant cross-reactivity)
VRC01: This review discusses host controls of bNAb responses and why highly antigenic vaccine Envs do not induce bNAbs when used as vaccine immunogens. In Kl mice expressing 3BNC60 germline unmutated common ancestor (UCA), majority of te none marrow B cell were deleted, and peripheral residual B cells were anergic. Vaccination resulted in GL B cells activated with minimal affinity maruration. Kelsoe2017 (review)
VRC01: 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)
VRC01: Compared to patient-derived mAbs, vaccine-elicited mAbs are often less able to neutralize the virus, due to a less-effective angle of approach to the Env spike. This study engineered an immunogen consisting of the gp120 core in complex with a CD4bs mAb, 17b. Rabbits immunized with this antigen displayed earlier affinity maturation and better virus neutralization compared to those immunized with the gp120 core alone. The 17b antibody was shown to have a steric clash with two other CD4bs Abs, GE136 and GE148, but not with VRC01. VRC01 and 2G12 bound to the the 17b-gp120 complex more avidly than to the gp120 core alone. Chen2016b (antibody binding site, vaccine antigen design, vaccine-induced immune responses, structure)
VRC01: This study describes a computational method to calculate the binding affinities of antibodies and antigens. The method called free-energy perturbation (FEP) was developed using HIV-1 Env gp120 and 3 VRC01-class mAbs, VRC01, VRC03, and VRC-PG04. Clark2017 (binding affinity, structure)
VRC01: 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)
VRC01: 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. Engineered variant VRC01-LS had greater persistence and improved protection against SHIV challenge, compared to VRC01. Pegu2017 (immunoprophylaxis, review)
VRC01: Prevalence, breadth, and potency of NAb responses in 98 CRF07_BC-infected individuals using a multi-subtype panel of 30 tier 2-3 Env-pseudotyped viruses were identified and the neutralization pattern of CRF07_BC-infected people was compared with that of subtype B'-infected individuals in China. 18% of 98 plasma samples neutralized >80% of viruses, and 53% neutralized >50%, suggesting the presence of broadly NAbs. CRF07_BC-infected individuals generated higher but less broad neutralization titers against intra-subtype viruses than subtype B'-infected individuals with longer infection length, indicating the transition from narrow autologous to broad heterologous neutralization over time. Neutralization activity of the top six plasmas from each cohort was attributable to the IgG fraction, and half of them developed CD4 binding site antibody reactivity. VRC01 and 2G12 were used as controls. Hu2017 (broad neutralizer)
VRC01: First population pharmacokinetics (PK) analysis of VRC01 was conducted using 84 HIV-uninfected adults who received multiple-dose intravenous or subcutaneous VRC01 every several weeks. The study demonstrated that a robust PK model of VRC01 could be developed to reliably characterize the observed PK data and to estimate VRC01 concentration values and associated variabilities at any post-dose time-point. Huang2017 (immunoprophylaxis)
VRC01: 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. Gristick2016 (glycosylation)
VRC01: This review summarizes vaccine approaches to counter HIV diversity. A structural map illustrated the contact regions of several bNAbs: VRC26.09, PGT128, CH235.12, and 10E8. Structures illustrating the bNAbs' tolerance for sequence variation were illustrated for CH235.12, PGT128, VRC26.09, and 10E8. CD4BS bNAbs such as VRC01 and CH235.12 illustrate that bNAbs bind to both conserved and hypervariable regions of Env. These bNAbs aren't broad because their epitopes are highly conserved, but rather they arise due to selective pressures of the autologous viruses. Korber2017 (antibody binding site, vaccine antigen design, review)
VRC01: 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)
VRC01: 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)
VRC01: 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)
VRC01: 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)
VRC01: A novel MHC-independent third-generation anti-HIV-1 CAR molecule (CD3ζ-CD28-CD137) has been reported.The extracellular domain is consisted of an scFv region derived from the bNAb VRC01 capable of redirecting the antigen specificity of primary CD8+ T cell populations against gp120. CAR cytoplasmic region, composed of a CD3ζ chain and multiple signaling domains (CD28 and CD137). The VC-CAR-T cells, were able to induce T cell-mediated cytolysis after coculture with gp120-expressing cells and wild-type HIV-1-infected CD4+ T cells. This also effectively induced the cytolysis of LRA-reactivated HIV-1-infected CD4 T lymphocytes isolated from infected individuals receiving sup-pressive cART. The data demonstrates that the special features of genetically engineered CAR-T cells make them a particularly suitable candidate for therapeutic application and constitute an improvement over existing CD4-based CAR-T technology. Liu2016 (CD4+ CTL, immunotherapy)
VRC01: 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 VRC01 to JRFL was abolished by mutation N279A. Kesavardhana2017 (vaccine antigen design, vaccine-induced immune responses)
VRC01: 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)
VRC01: 24 participants received VRC01 as immunotherapy during ART treatment interruption. VRC01 delayed viral rebound by approximately 4 to 6 weeks. VRC01 exerted pressure on the rebounding virus, resulting in selection for neutralization-resistant viruses. Bar2016 (immunotherapy)
VRC01: 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)
VRC01: Chimeric antigen receptors, i.e., fusion proteins made from single-chain antibodies, may be a useful approach to immunotherapy. A set of mAbs were chosen based on their binding to a variety of sites on Env and availability of antibody sequences. The chimeric receptors were created by fusing the antibody's heavy chain, light chain, and two signaling domains into a single molecule. All 7 antibodies used to make the chimeric receptors (10E8, 3BNC117, PGT126, VRC01, X5, PGT128, PG9) showed specific killing of HIV-1 infected cells and suppression of viral replication against a panel of HIV-1 strains. Ali2016 (immunotherapy, chimeric antibody)
VRC01: This review classified and mapped the binding regions of 32 bNAbs isolated 2010-2016. Wu2016 (review)
VRC01: In neutralization assays of antibody mixtures, there was a modest synergy between the CD4bs VRC01 and either of the two CD4i MAbs E51 and 412d. The synergy is likely the result of the ability of CD4i antibodies (E51 or 412d) to induce the open state and facilitate access to the CD4 binding site. The presence of E51 enhanced the Env binding of VRC01, NIH45-46, NIH45-46^G54W, and to a lesser extent 3BNC117. Gardner2016 (antibody interactions)
VRC01: 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)
VRC01: 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)
VRC01: 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)
VRC01: This study estimated intra-lineage longitudinal evolutionary rate changes for the VRC26 and CH103 lineages and compared these to the reported rate changes of the VRC01 lineage. Results confirmed that a decreasing evolutionary rate is common to all three lineages. Sheng2016 (antibody lineage)
VRC01: 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, VRC01 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)
VRC01: 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)
VRC01: 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, VRC01, was able to neutralize and bind B41 pseudovirus and trimer well. Pugach2015
VRC01: 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
VRC01: 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 CD4bs binding bNAbs, VRC01 recognizes trimer similarly to CH103, CH106, 3BNC117 and 1NC9, and is inhibited by sCD4. VRC01 enhanced binding of non-NAb 17b. outer domain (OD)-glycan bNAbs, PGT135 and PGT136, though ˜ 5x less efficient binders of trimer, were able to unidirectionally inhibit binding of VRC01, as also other CD4bs bNAbs, 3BNC117, 2BNC60, NIH45-46. Derking2015 (antibody interactions, neutralization, binding affinity, structure)
VRC01: 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 CD4bs bNAb VRC01 but trimer DU442 and its pseudotyped virus are weakly reactive with VRC01. The structure of a complex of ZM197M SOSIP.664 with VRC01 Fab at 9.6 A by cryo-EM had a 0.96 correlation with the structure of the Clade A trimer. Julien2015 (assay or method development, structure)
VRC01: 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 VRC01 to trimers was minimally affected by trimer cross-linking. Schiffner2016 (assay or method development, binding affinity, structure)
VRC01: 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 VRC01. vandenKerkhof2016 (elite controllers, neutralization, escape)
VRC01: 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 10/20 BG505 SOSIP.664-D7324 trimer-immunized rabbits were capable of inhibiting VRC01 binding to CD4bs, but gp140-immunized sera could not. 4/4 similarly trimer-immunized macaque sera also inhibited VRC01 binding. Serum inhibition of VRC01-trimer binding significantly correlated with rabbit autologous neutralization of the trimer-equivalent psuedovirus, BG505.T332N. Sanders2015 (antibody generation, neutralization, binding affinity, polyclonal antibodies)
VRC01: 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 VRC01 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)
VRC01: 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. VRC01 was one of the first CD4bs antibodies identified, and it has been tested in both prophylactic and therapeutic human trials. Stephenson2016 (immunotherapy, review)
VRC01: This paper describes modifications that expand the germ line VRC01-class antibody-recognition potential of the previously described 426c Env. The authors show that an optimized Env immunogen can engage multiple germ line VRC01-class antibodies. McGuire2016 (antibody interactions, antibody lineage)
VRC01: This review discusses the breakthroughs in understanding of the biology of the transmitted virus, the structure and nature of its envelope trimer, vaccine-induced CD8 T cell control in primates, and host control of bnAb elicitation. Haynes2016 (review)
VRC01: This study described a natural interaction between Abs and mucin protein, especially, MUC16 that is enhanced in chronic HIV infection. Agalactosylated (G0) Abs demonstrated the highest binding to MUC16. Binding of Abs to epithelial cells was diminished following MUC16 knockdown, and the MUC16 N-linked glycans were critical for binding.These point to a novel opportunity to enrich Abs at mucosal sites by targeting Abs to MUC16 through changes in Fc glycosylation, potentially blocking viral movement. Surface plasmon resonance (SPR) was performed to determine the binding affinity of Fc, Fab, and F(ab)2 of VRC01 to MUC16. They determined the relative percentage of G0, G1, and G2 glycan structures and the enhanced MUC16 binding with VRC01 was linked to higher G0 glycosylation. Gunn2016 (antibody interactions, glycosylation)
VRC01: 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. VRC01 was compared to the newly-derived mAbs; it tested positive in one assay of cross-reactivity with gut bacteria, and positive in one test of autoreactivity. Jeffries2016 (antibody polyreactivity)
VRC01: 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). CD4bs-directed VRC01 potently neutralizes BG505.T332N pseudovirus and binds strongly to all 3 antigens with slow dissociation. Yasmeen2014 (antibody binding site, assay or method development)
VRC01: 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. VRC01 has been used as a control in testing CD4 binding site neutralizing specificity of the sera. Sanchez-Merino2016 (neutralization, acute/early infection)
VRC01: This review summarized the novel strategies for HIV vaccine discovery. Multiple therapeutic vaccines have failed in the past, in a non placebo controlled trial, a Tat vaccine demonstrated immune cell restoration, reduction of immune activation, and reduced HIV-1 DNA viral load. bNAbs offer both prevention potential and treatment. In early-phase clinical trials, VRC01 reduced viral load in HIV-1-infected individuals not on HAART. Gray2016 (vaccine antigen design, vaccine-induced immune responses, HAART, ART, review)
VRC01: 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 VRC01 (and all other Abs besides PGT128) there was no significant difference in neutralization between pre-seroconversion and post-seroconversion viruses. When viruses from 3 time periods were compared, breadth remained constant, but potency decreased, indicating that the C clade epidemic is becoming increasingly resistant to VRC01. 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)
VRC01: 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, second-generation mAb, VRC01 when compared had a geometric mean of IC₅₀=2.13 µg/ml for 11/12 viruses it neutralized at a potency of 92%. 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)
VRC01: 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-CD4bs bNAb VRC01 was able to neutralize only 1/16 tested non-M primary isolates at an IC₅₀< 10µg/ml, RBF208,M/O at 3.64 µg/ml. Morgand2015 (neutralization, subtype comparisons)
VRC01: 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. VRC01, a CD4bs bnAb belonged to a group with slopes >1. Webb2015 (neutralization)
VRC01: 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-VRC01 precursor did not bind to any trimers. Sliepen2015 (binding affinity, antibody lineage)
VRC01: 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. NIH45-46GL and 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)
VRC01: 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. For VRC01 The time to maximal concentration in the plasma was 24 h, independent of dose, and the serum (plasma) half-life of VRC01 was 3.9–4.2 d. All NmAb-treated macaques were free of virus in blood and tissues at 6 months after exposure. Hessell2016 (neutralization, acute/early infection, immunotherapy, mother-to-infant transmission)
VRC01: Donor EB179 was a long-term non-progressor with high serum neutralization breadth and potency. 8 B-cell clones produced Abs, including 179NC75 which 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 VRC01's neutralizing 7/9 of the same psuedoviral panel. 179NC75 was also more potent than VRC01 against 8 viruses of a 22 Tier-2 clade B panel. Freund2015 (neutralization, broad neutralizer)
VRC01: 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 VRC01 had weak ADCC. Bruel2016 (ADCC, binding affinity)
VRC01: This review discusses the structural characteristics of bNAbs, how they recognize the virus, and new vaccination strategies that aim to guide B cells to produce protective Abs. The evolutionary lineage of VRC01 in the donor has been extensively studied. Although VRC01 had a 5-fold lower mutation rate than other bNAbs, such as CA256-VRC26 and CH103, it seems likely that the principles that guide VRC01 bNAb development will apply to other bNAb ontogenies. Sadanand2016 (vaccine antigen design, review)
VRC01: 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)
VRC01: 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)
VRC01: In 5 years additional members of the CH235 clonal lineage were isolated based on deep sequencing of donor CH505's V_L and V_H chains at 17 timepoints in the donor's infection. Two of these had greater neutralization potency, CH235.9 and CH235.12. Study of crystal structures indicated a site of vulnerability near the Env CD4 binding site. The lineages of CH103 and CH235, both derived from Donor CH505 were compared - CH103 lineage K_d increased an order of magnitude each step of maturation but maintained a fast association rate; CH235 lineage however, had slower K_ds and K_as over maturation. VRC01 was used as a control and neutralized 89% of a 202-multiclade Env-psuedovirus panel at a potency of <50 µg/ml. Despite using VH1-46, the CH235.9 and CH235.12 neutralizing profiles were more similar functionally to that of VH1-2-derived antibody VRC01. Structurally, both VRC01 and the CH235 bNAbs mimic CD4 to bind virus, preserving contacts with gp120 D368. Bonsignori2016 (neutralization, binding affinity, antibody sequence)
VRC01: A germline-targeting immunogen (eOD-GT8) was developed to elicit VRC01-class bNAbs. HIV-naive humans were shown to have VRC01-class precursor naive B cells that responded to this immunogen. Not only are the eOD-GT8 isolated naïve B cells highly enriched for VRC01-class core characteristics of VH1-02 and a 5–amino acid L-CDR3, they possess further refined sequence attributes of VRC01-class bNAbs. Jardine2016 (vaccine antigen design, immunotherapy, antibody lineage)
VRC01: 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. Mutations in either of the loop D or V5 regions (or both) may be critical for natural evasion of VRC01. However, the resistance mechanisms are currently unknown and four CRF01 AE viruses, CNAE08, CNAE14, CNAE17, and CNAE31, were demonstrated to be resistant to VRC01. Exchanging the V5 region alone did not affect the sensitivity of the viruses to VRC01.CNAE09, CNAE10, and CNAE11 strains containing the asparagine residue at position 461 were still highly sensitive to VRC01. CNAE17 demonstrated the highest levels of resistance may be due to the presence of mutation S365P in the CD4bs. Chen2016 (neutralization, subtype comparisons)
VRC01: Four bNAbs (VRC01, VRC01-LS, 3BNC117, and 10-1074) were administered, singly or in combination, to macaques, followed by weekly challenges with clade B SHIV_AD8. In all cases, the administration of MAbs delayed virus acquisition. Control animals required 2 to 6 challenges before becoming infected, while animals receiving VRC01 required 4–12 challenges; 3BNC117 required 7–20 challenges; 10-1074 required 6–23 challenges; and VRC01-LS required 9–18 challenges. Animals that received a single antibody infusion resisted infection for up to 23 weekly challenges. Gautam2016 (immunotherapy)
VRC01: 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. VRC01 neutralized 89% of the 199 viruses tested. Hraber2014 (neutralization)
VRC01: 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. VRC01 was one of the antibodies in the VH-gene-restricted class. Zhou2015 (neutralization, structure, antibody lineage, broad neutralizer)
VRC01: 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)
VRC01: 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)
VRC01: 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%). For this Ab CDR H3 length is 12 and VH changes 32%, Vk nucleotide change is 18%. Wu2015 (antibody lineage)
VRC01: A VRC01 drug product was administered to 23 participants: 15 were on ART, and 8 were viremic and not receiving ART. The treatment reduced viremia significantly only in the viremic subjects. In 4 of these subjects, the reduction in viremia was accompanied by outgrowth of viruses that were less neutralization-sensitive. Lynch2015 (immunotherapy)
VRC01: 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. VRC01 targets the outer domain of gp120. Georgiev2013a (review)
VRC01: 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)
VRC01: A previous study demonstrated the presence of VRC01-resistant strains in an HIV-1 infected patient during antiretroviral therapy. This study report follow-up of two subsequent samples, CRF08-BC env clones,CNE47 and CNE48 from the same patient. With genetic and phenotypic analysis it showed that VRC01-resistant HIV-1 continued to exist and the resistant phenotype was associated with a single asparagine residue at position 460 (N460), a potential N-linked glycosylation site in the V5 region. Guo2014
VRC01: 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. VRC01 was only partially effective in blocking cell to cell transmission. Malbec2013
VRC01: 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)
VRC01: This review surveyed the Vectored Immuno Prophylaxis (VIP) strategy, which involves passive immunization by viral vector-mediated delivery of genes encoding bnAbs for in vivo expression. Recently published studies in humanized mice and macaques were discussed as well as the pros and cons of VIP towards clinical applications to control HIV endemics. A single injection of AAV8 vector achieved peak Ab production in serum at week 6.VRC01 could provide full protection against HIV challenge (10 ng) at a titer of 8.3 μg/mL conforming the superiority over b12. Yang2014 (immunoprophylaxis, review, antibody gene transfer)
VRC01: Engineered nanoparticle immunogens eOD-GT8 in 60mer and 3mer form bound VRC01 bNAb precursors and induced VRC01-class bNAbs with classic short CDRL3 in a VRC01 gH (approximated germline-reverted heavy chain precursor) knock-in mouse. Induced antibodies had mutations favoring binding to near-native gp120 constructs. Jardine2015 (antibody generation, enhancing activity, broad neutralizer)
VRC01: 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)
VRC01: The heavy and light chains of VRC01 were stably expressed in tobacco plant cells. The resulting antibody had neutralization breadth and potency similar to that produced in HEK cells. The results demonstrate a method for low-cost production of anti-HIV antibodies. Teh2014 (antibody gene transfer)
VRC01: 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)
VRC01: 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)
VRC01: VRC01 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 3/5 chronic Envs, 4/6 Consensus Envs and 6/7 T/F Envs. Liao2013c (antibody interactions, binding affinity)
VRC01: Study evaluated 4 gp140 Env protein vaccine immunogens derived from an elite neutralizer donor VC10042, an HIV+ African American male from Vanderbilt cohort. Env immunogens, VC10042.05, VC10042.05RM, VC10042.08 and VC10042.ela, elicited high titers of cross-reactive Abs recognizing V1/V2 regions. All the Env protein except VC10042.05 bound to VRC01, although weak binding was detected with VC10042.05 monomer. Parental Env of VC10042.ela was highly neutralized by VRC01. Carbonetti2014 (elite controllers, vaccine-induced immune responses)
VRC01: The effect of low pH and HIV-1 Abs which increased the transcytosis of the virus by 20 fold, has been reported. This enhanced transcytosis was due to the Fc neonatal receptor (FcRn), which facilitates HIV-1's own transmission by usurping Ab responses directed against itself. Both infectious and noninfectious viruses were transcytosed by VRC01. Gupta2013
VRC01: A set of potent VRC01-like (PVL) MAbs were generated from VRC01-derivatve NIH45-46^G54W and they were more potent than even NIH45-46 or NIH45-46^G54W, cross-recognizing viruses across clades. The novel antibodies designed based on crystal structure were NIH45-46m2, NIH45-46m7, NIH45-46m25 and NIH45-46m28, with NIH45-46m2 being the single most broad and potent antibody till date. 45-46m2 and 45-46m7 in combination with each other and a third antibody were able to thwart viral escape routes. Diskin2013
VRC01: 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. VRC01 showed very high neutralization titer against BG505 pseudovirus in a competitive binding assay as shown in Table 1. Hoffenberg2013 (antibody interactions, neutralization)
VRC01: This study evaluated the frequency of anti-gp120 B cells in follicular (FO) and marginal zone (MZ) B cells compartments of naive WT mice and human populations. Mouse MZ B cells use IGHV1-53, closely related to human IGHV1-2*02 that encodes VRC01, to generate gp120-specific Abs. VRC01 bound very well to RSC3, but IGHV1-53 didn't. These MZ B cell derived germline Abs showed similarity to purported VRC01 germline and are not protective against HIV. Pujanauski2013 (antibody lineage)
VRC01: 4 new variants of VRC07, a MAb from the VRC01 class of neutralizing antibodies were generated using structure-guided optimization and were between 4 and 5.7 times more potent than VRC01. Rudicell2014
VRC01: 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.VRC01 neutralized 92% of a cross-clade panel of 157 HIV-1 isolates (Fig. S1) while 1F7 neutralized only 20% of the isolates. Gach2013 (neutralization)
VRC01: 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. VRC01 was used as a reference Ab in neutralization assay comparing A3R5 and TZM-bl. McLinden2013 (assay or method development)
VRC01: 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. VRC01 is a CD4bs Ab, with breadth 87%, IC₅₀ 0.98 μg per ml, and its unique feature is CD4 mimicry by its VH1-2-derived heavy chain. Similar MAbs include VRC02, VRC03, NIH45-46, 3BNC60, BNC62, 3BNC117, 12A12, 12A21, 12A30, VRC-PG04, VRC-CH31. Kwong2013 (review)
VRC01: 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. VRC01 was used in CD4 coexpression and competitive binding assay. Veillette2014 (ADCC)
VRC01: The ability of MAb A32 to recognize HIV-1 Env expressed on the surface of infected CD4(+) T cells as well as its ability to mediate antibody-dependent cellular cytotoxicity (ADCC) activity was investigated. This study demonstrates that the epitope defined by MAb A32 is a major target on gp120 for plasma ADCC activity. VRC01 was used as a control and A32 showed >3 fold higher ADCC activity than VRC01. Ferrari2011a (ADCC)
VRC01_d45: The 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. It is reported that glutamic acid to glutamine mutation at residue 96 decreased the binding affinity to 10 fold in VRC01. Zhou2013a (antibody sequence, structure, antibody lineage)
VRC01: 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.) Zhu2013a (antibody sequence)
VRC01: Series of VRC01 and 10E8 variants with partial framework reversions to germline in both H and L chains were created and their neutralization activity was compared to that of the mature antibody. Some of these Abs retained broad and potent neutralization activity even when their framework regions were substantially reverted back to germline, suggesting the promise of partial framework reversion for Ab optimization. Georgiev2014 (neutralization, antibody lineage)
VRC01: 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)
VRC01: 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. Sensitivity to the CD4bs VRC01 and VRC03 mAbs was increased in the N276D mutated viruses. Balla-Jhagjhoorsingh2013 (glycosylation)
VRC01: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 very little with the VRC01 although the binding sites are in close proximity. JM4 IgG2b was able to potently neutralize the HIV-1 isolates that were resistant to VRC01. Acharya2013 (neutralization)
VRC01: This is a review of a satellite symposium at the AIDS Vaccine 2012 conference, focusing on antibody gene transfer. Dennis Burton showed that PGT121 provides protection in lower in vivo concentrations than b12. Balazs2013 (immunoprophylaxis)
VRC01: 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 VRC01, against 181 diverse HIV-1 strains with available Ab-Ag complex structures. Chuang2013 (computational epitope prediction)
VRC01: The complexity of the epitopes recognized by ADCC responses in HIV-1 infected individuals and candidate vaccine recipients is discussed in this review. VRC01 is discussed as the CD4bs-targeting, neutralizing anti-gp120 mAb exhibiting ADCC activity and having a discontinuous epitope. Both VRC01 and b12 recognize the outer domain of gp120. b12 recognizes using Ab heavy chain, where as VRC01 uses both heavy and light chains. This differences is crucial for their neutralization breadth. Pollara2013 (ADCC, review)
VRC01: "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)
VRC01: Cryoelectron tomography was used to determine structures of A12, m36, or m36/CD4 complexed to trimeric Env displayed on intact HIV-1 BaL virus. 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)
VRC01: 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 Ab-bound states. VRC01 was mentioned in the context of CD4 binding sites. Korkut2012 (structure)
VRC01: 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. VRC01 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)
VRC01: 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. VRC01 was used as an anti CD4 binding Ab to study effects of Ab specificity and affinity on ADCC against HIV-1 infected targets. Smalls-Mantey2012 (ADCC, assay or method development)
VRC01: 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)
VRC01: 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. VRC01 was used as a broadly reactive CD4bs MAb to compare neutralizing specificity of VRC06. Li2012
VRC01: This is a comment on Tan2012. It is noted that Tran and colleagues used high-resolution 3D cryoelectron tomography to define the conformation of Env when bound to soluble CD4 and to a series of monoclonal antibodies. It was demonstrated that antibodies binding to the CD4 binding site or coreceptor binding site of Env may lead to significantly different conformations of the trimeric Env complex. VRC01 locks the complex in a closed conformation, while binding to soluble CD4 or the monoclonal antibody 17b fixed the trimer in an open conformation. Wright2012 (novel epitope)
VRC01: Previous cryo-electron tomographic studies were extended. A more complete picture of the HIV entry process was presented by showing that HIV-1 Env binding to either soluble CD4 (sCD4) or the co-receptor mimic 17b leads to the same structural opening, or activation, of the Env spike. Atudy also demonstrated structurally that the broadly neutralizing antibodies VRC01, VRC02, VRC03 are able to block this activation, locking Env in a state that resembles closed, native Env. The cryo-electron microscopic structure of soluble trimeric Env in the 17b-bound state is presented at ˜9 Å resolution, revealing it as a novel, activated intermediate conformation of trimeric Env that could serve as a new template for immunogen design. Tran2012 (structure)
VRC01: Efficacy of VRC01 as a topically administered microbicide to prevent sexual transmission was evaluated in a RAG-hu humanized mouse model of vaginal HIV-1 transmission. A combination of MAbs b12, 2F5, 4E10 and 2G12, was used as a positive efficacy control. 7/9 VRC01 antibody administered mice and all of the mice receiving the four bNAb antibody combination were protected against HIV-1 challenge. Veselinovic2012 (immunoprophylaxis)
VRC01: Two genetically related and two unrelated envelope clones, derived from CRF08_BC-infected patients, with distinct VRC01 neutralization profiles were studied, and 22 chimeric envelope clones were generated by interchanging the loop D and/or V5 regions between the original envelopes or by single alanine substitutions within each region. Interchanging the V5 region between the genetically related or unrelated clones completely swapped their VRC01 sensitivity profiles. Asn-460, a potential N-linked glycosylation site in the V5 region, was a key factor for observed resistance. The long side chain of Asn-460, and potential glycosylation, may create steric hindrance that lowers binding affinity, thereby increasing resistance to VRC01 neutralization Guo2012 (neutralization, structure)
VRC01: 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). VRC01 neutralized 71% of these viruses. Goo2012 (neutralization, rate of progression)
VRC01: 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 ba