Advanced Step in HIV Vaccine Development
A significant step in the fight against HIV, the new DHVI vaccine has showcased early promise in generating broadly neutralizing antibodies, crucial for an effective HIV vaccine. Despite a temporary halt due to a minor allergic reaction, this pivotal development illuminates a hopeful path toward eradicating the virus.
The quest for an effective HIV vaccine has witnessed a significant milestone with the development of a new vaccine candidate, DHVI. This promising development emerged from recent early-stage clinical trials, marking an important advancement in the fight against HIV/AIDS.
Promising Early Results
In these initial trials, the DHVI vaccine has shown the potential to generate broadly neutralizing antibodies (bnAbs), which are crucial for an effective HIV vaccine. These antibodies have the capability to recognize and neutralize various strains of HIV, addressing one of the primary challenges in vaccine development. The trials, although small, indicated that the vaccine could successfully induce bnAbs in several participants after just two doses.
Challenges & Cautions
Despite these promising results, the trial encountered a setback when it was halted due to a non-life-threatening allergic reaction in a participant, believed to be linked to an additive in the vaccine. This pause underscores the complexities involved in vaccine development, where ensuring safety is as critical as efficacy.
Dr. Barton F Haynes, the director of the Duke Human Vaccine Institute and a senior author of the study, emphasized the significance of these findings. According to Dr. Haynes, this breakthrough demonstrates the feasibility of inducing potent antibodies that can tackle even the most resilient HIV strains. The research team is optimistic but acknowledges that there’s still a considerable journey ahead to refine and enhance the vaccine’s effectiveness and safety.
Next Steps in Research
The path forward involves enhancing the vaccine’s ability to induce more potent neutralizing antibodies and expanding its efficacy to prevent virus escape. The research team is geared up for the next phases, which will focus on broader and more comprehensive trials to ascertain the long-term efficacy and safety of the vaccine.
The development of the DHVI vaccine represents a beacon of hope in the long-standing battle against HIV. While the journey toward a universally effective HIV vaccine continues, the achievements of this trial provide a clearer and more hopeful path forward. With continued research and refinement, the dream of a reliable HIV vaccine appears increasingly within reach.
(For detailed insights, including the scientific discussions and data, you can access the full study published in Cell (https://www.cell.com/cell/fulltext/S0092-8674(24)00459-8).
Here is the summary of the study:
Vaccine Induction of Heterologous HIV-1-Neutralizing Antibody B Cell Lineages:
– Study on human vaccine induction of heterologous HIV-1-neutralizing antibody B cell lineages.
– Researchers from various institutions contributed to the study.
Authors and Affiliations:
– Key authors include Wilton B. Williams, S. Munir Alam, Gilad Ofek, and more.
– Affiliations span multiple institutes including Duke Human Vaccine Institute and University of Maryland.
Significance of the Study:
– The study aims to understand the immune response to HIV-1 through vaccination.
– Results could lead to advancements in HIV-1 treatment and prevention.
Collaborative Research Efforts:
– Collaboration between different institutions indicates a comprehensive approach to the study.
– Diverse expertise pooled to enhance the understanding of HIV-1 immune response.
Implications for the Medical Field:
– Findings may contribute to the development of effective HIV-1 vaccines.
– Understanding vaccine-induced antibody responses crucial for combating HIV-1.
Multi-Disciplinary Approach:
– Involvement of experts from varying fields like immunology and genetics.
– Integration of knowledge for a holistic exploration of HIV-1 neutralizing antibodies.
Potential for Future Studies:
– Study forms a foundation for further investigations into HIV-1 vaccine strategies.
– Future research could focus on optimizing vaccine-induced immune responses.
Contribution to Vaccine Development:
– Insights from the study could guide the development of novel vaccine candidates.
– Potential breakthroughs in HIV-1 vaccine design and efficacy expected.
Vaccine-induced Antibody Response:
– A clinical trial studied a peptide/liposome immunogen targeting B cell lineages of HIV-1 envelope (Env) membrane-proximal external region (MPER) broadly neutralizing antibodies (bnAbs).
– The study reported peptide-liposome induction of polyclonal HIV-1 B cell lineages of mature bnAbs and their precursors, with the most potent antibodies neutralizing 15% of global tier 2 HIV-1 strains.
Impact of Immunization:
– Neutralization was enhanced by vaccine selection of improbable mutations that increased antibody binding to gp41 and lipids.
– Lineage initiation occurred after the second immunization, demonstrating proof of concept for rapid vaccine induction of human B cell lineages with heterologous neutralizing activity.
Global Health Priority:
– Development of a preventive HIV-1 vaccine is a global health priority.
– Previous vaccine efficacy trials showed insufficient protection from HIV-1, except for one trial in Thailand with 31.2% estimated efficacy.
Challenges in Vaccine Development:
– Previous HIV-1 vaccine trials have failed to induce broadly neutralizing antibodies, and an alternative pox-protein prime boost vaccine in South Africa showed no efficacy against subtype C HIV-1 infections.
Current Status of HIV-1 Vaccines:
– HIV-1 envelope (Env)-containing vaccines tested to date have only induced non-neutralizing antibodies, presenting a significant challenge for HIV vaccine development.
Author Insights:
– Authors emphasized the critical need to address the roadblock in HIV vaccine development and the potential for successful path through the study’s findings.
– The study outlines a path for inducing human B cell lineages with heterologous neutralizing activity and the selection of improbable mutations.
Strategies for Improved Vaccine Efficacy:
– Researchers have highlighted the necessity for strategies that induce broadly neutralizing antibodies to overcome the challenges faced in HIV-1 vaccine development.
– The study’s findings provide a potential pathway for rapid induction of human B cell lineages with heterologous neutralizing activity.
Perspectives on Vaccine Trials:
– The study’s results shed light on the significant challenges and the urgent need for effective HIV-1 vaccine development, especially in light of previous trials’ limited efficacy.
– The generation of polyclonal HIV-1 B cell lineages of mature broadly neutralizing antibodies represents a promising advancement in HIV-1 vaccine research.
Development of HIV-1 Vaccines:
– Recent vaccine trials have shown a promising gene expression signature that correlates with protection against SIV and HIV.
– Strategies are being developed to induce broadly neutralizing antibodies for effective HIV-1 vaccines.
Role of Broadly Neutralizing Antibodies (bnAbs):
– Broadly neutralizing antibodies can protect against SHIV challenges in monkeys.
– Inducing heterologous HIV-1-neutralizing antibodies is a key goal in HIV vaccine development.
Vaccine-Induced Protection:
– Vaccine-induced protection in nonhuman primates depends on serum-neutralizing antibody titers.
– Stabilized HIV-1 envelope immunization leads to neutralizing antibodies and protection against mucosal infection.
Neutralizing Antibodies and HIV Prevention:
– Neutralizing antibodies have shown promise in preventing HIV-1 acquisition in clinical trials.
– Targeting specific regions like the gp41 membrane-proximal external region (MPER) can induce bnAbs.
Latest Advances in Neutralizing Antibodies:
– MPER-targeted antibodies exhibit broad neutralization breadth.
– Human monoclonal antibodies targeting novel epitopes on gp41 show potent cross-clade neutralization.
Potency of Broad HIV-Neutralizing Antibodies:
– Memory B cells and plasma contain potent and broad HIV-neutralizing antibodies.
– Specific gp41-targeted human antibodies demonstrate broad neutralization capabilities against HIV-1.
Identification of Cross-Reactive HIV-1-Neutralizing Antibodies:
– Cross-reactive HIV-1-neutralizing human monoclonal antibodies have been identified in patients with specific antibody profiles.
– Ongoing research aims to harness the potential of these antibodies for HIV prevention.
Location of MPER and Epitopes:
– The MPER is physically located near the virion lipid membrane, with key epitopes for both proximal and distal MPER bnAbs identified.
– Proximal epitope with prototype bnAb 2F5 core epitope ELDKWA at Env positions 662–667, and distal epitope with prototype bnAb 4E10 core epitope NWFDIT at positions 671–676.
Role of Polyspecificity and Lipid Reactivity:
– Polyspecificity and lipid reactivity play a crucial role in binding broadly neutralizing anti-HIV-1 antibodies 2F5 and 4E10 to glycoprotein 41 membrane proximal envelope epitopes.
– Binding to lipids has been proposed to tether the bnAb to the virion membrane to enable binding to gp41 MPER bnAb epitopes.
Cell Surface Tethering and Neutralization Assay:
– A neutralization assay detecting MPER bnAb precursors promotes tethering of MPER-reactive antibodies on the cell surface via FcγRI/CD64 expression in the TZM-bl infection indicator cell line.
– Utilization of immunoglobulin G Fc receptors by HIV-1 is specifically facilitated by antibodies against the membrane-proximal external region of gp41.
Induction of Broad Neutralizing Antibodies and Challenges:
– Lipid binding is essential for the broad neutralizing activity of MPER bnAbs, but induction of antibodies to self-lipids has been a substantial roadblock in MPER bnAb elicitation.
– Potent bnAbs develop in individuals living with HIV-1, but only rarely and after prolonged periods following transmission.
HIV-1 Neutralizing Antibodies:
– The development of broadly neutralizing antibodies (bnAbs) in HIV-1-infected individuals has been a topic of interest.
– A maturation pathway from germline to broad HIV-1 neutralizer of a CD4-mimic antibody has been studied.
Strategies for HIV-1 Vaccines:
– Strategies for HIV-1 vaccines that induce broadly neutralizing antibodies have been explored.
– B-cell-lineage immunogen design aims to rapidly induce bnAbs via sequential immunizations.
MPER Peptide-Liposomes:
– MPER peptide-liposomes have been designed with proximal and distal MPER bnAb epitopes.
– Induction of antibodies in rhesus macaques that recognize a fusion-intermediate conformation of HIV-1 gp41 has been demonstrated.
B Cell Lineage Immunogen Design:
– The B cell lineage immunogen design aims to more rapidly induce bnAbs by selecting Envs that bind with high affinity to bnAb lineage naive or unmutated common ancestor B cell lineage precursors.
– An MPER peptide-liposome that binds to a bnAb unmutated ancestor antibody induces polyclonal MPER epitope-targeted antibodies that neutralize heterologous HIV-1 strains in humans.
Functional Relevance of Improbable Antibody Mutations:
– The functional relevance of improbable antibody mutations for HIV broadly neutralizing antibody development has been investigated.
– The B cell lineage immunogen design seeks to rapidly select for improbable bnAb BCR mutations via vaccination.
HVTN 133 Clinical Trial:
– The immunogen used in the HVTN 133 trial was an MPER peptide-liposome designed to bind to an unmutated ancestor antibody of a prototype proximal MPER bnAb, 2F5.
– Vaccine-induced MPER clonal B cell lineage acquired neutralization of 15% of global or heterologous tier 2 HIV-1 strains and 35% of clade B HIV-1 strains.
HVTN 133 Clinical Trial Overview:
– The HVTN 133 clinical trial tested MPER peptide-liposomes in low and high-dose groups.
– 20 participants were enrolled, with successful induction of serum binding antibody responses.
Immunization Results:
– One participant experienced an anaphylaxis reaction after the third immunization.
– After two immunizations, 65% of vaccinees exhibited serum binding antibodies to the MPER bnAb epitope.
Neutralizing Antibody Activity:
– Two of five individuals showed weak tier 2 HIV-1-neutralizing activity after three immunizations.
– B cell repertoire analysis was conducted on individuals receiving three immunizations.
Peripheral Blood B Cell Repertoire:
– MPER-reactive B cells were isolated from vaccinees post 3rd immunization.
– 87 MPER+ antibodies were identified, with 86% being MPERΔ antibodies.
Induction of B Cell Lineages:
– Multiple responder vaccinees showed induction of serum binding antibody responses.
– High responders in the low-dose group had increased MPER+ memory B cell isolation.
MPER Peptide-Liposome Immunization:
– Boosted frequency of MPER+ antibodies from baseline in vaccinees 133-23 and 133-39.
– Frequency increased to around 1 in 11,100 B cells and 1 in 25,000 B cells respectively after three immunizations.
B Cell Repertoire Analysis:
– Differential binding antibodies were identified with characteristics of bnAb B cell lineages.
– Vaccinees 133-23 and 133-39 in the low-dose group were high responders for MPER+ memory B cells.
Polyclonal MPER Elicitation:
– The HVTN 133 clinical trial elicited a polyclonal MPER response.
– Immunization boosted MPER+ antibody frequency in B cells post immunizations.
Vaccine-Induced VH Gene Usage in MPER+ Antibodies:
– MPER+ antibodies post-3rd immunization predominantly used VH7-4-1, VH5-51, VH2-5, and VH3-49 genes.
– Higher V gene frequencies observed in vaccine-induced MPER+ antibodies compared to pre-vaccination antibodies.
Characteristics of Light Chains in MPER+ Antibodies:
– Post-vaccination MPER+ antibodies displayed diversity in light chains, with common Vκ genes being Vκ4-1, Vκ1-39, and Vκ3-20.
– Vaccine-induced MPER+ antibodies had higher heavy- and light chain mutation frequencies compared to antigen-unbiased antibodies.
HCDR3 Length Variation in MPER+ Antibodies:
– VH2-5 and VH3-49 MPER+ antibodies had shorter HCDR3 lengths compared to VH7-4-1 and VH5-51 antibodies.
– Polyreactivity is a common trait observed in MPER bnAbs.
Polyreactivity of MPER bnAbs:
– MPER bnAb 2F5 exhibited cross-reactivity with human protein KYNU.
– MPER+ antibodies using VH2-5 were highly polyreactive, interacting with KYNU and clinical autoantigens.
Autoantigen Recognition by MPER+ Antibodies:
– 29/87 post-3rd immunization MPER+ antibodies bound to KYNU, clinical autoantigens, and/or cardiolipin.
– VH2-5 MPER+ antibodies were notably polyreactive and showed binding to KYNU-Δ.
Implications of HCDR3 Length in 2F5-like Abs:
– VH2-5-using putative 2F5-like Abs had shorter HCDR3 lengths compared to 2F5 bnAb.
– The shorter HCDR3 lengths of VH2-5-using Abs suggest limited progression to bnAb status.
Strategies for HIV-1 Vaccines:
– Strategies are being developed to induce broadly neutralizing antibodies against HIV-1.
– MPER epitope targeting key for vaccine development.
HIV-1 Neutralization Activity:
– MPER+ antibodies showed neutralization of tier 1 and tier 2 HIV-1 strains.
– A total of 49 MPER+ neutralizing antibodies from 24 clonal lineages exhibited HIV-1 neutralization.
VH7-4-1 Heavy Chain Gene:
– VH7-4-1 heavy chain gene utilized in MPER+ antibodies.
– VH7-4-1∗02 allele most common, found in ∼43% of individuals.
MPER+ Antibody Clonal Lineage DH1317:
– DH1317 B cell lineage included 11 IgG MPER+ antibodies with distinct characteristics.
– Several mature DH1317 members demonstrated potent neutralization of tier 2 clade B HIV-1 strains.
Neutralization Breadth Profile:
– Several DH1317 lineage antibodies neutralized both tier 1 and tier 2 HIV-1 strains.
– Neutralization potency enhanced in TZM-bl/FcγRI cells.
MPER+ NAbs Mapping:
– DH1317 antibodies and intermediates mapped to proximal bnAb epitopes.
– DH1317.4 and DH1317.9 showed potent neutralization of tier 2 clade B HIV-1 strains.
Global Panel Testing:
– DH1317.4 bnAb tested against a global panel of 197 HIV-1 strains.
– Studies on neutralizing antibodies continue for HIV-1 prevention.
Future Immunogenetics Research:
– Immunogenetics of MPER+ antibody response remains a focus.
– Further exploration of neutralizing potentials and genetic interactions expected.
Impact on Antibody Recognition:
– Recent HIV-1 clade C viruses have features affecting antibody recognition.
– Implications for active and passive immunization discussed.
Identification of Neutralizing Antibodies:
– Antibodies DH1317.4 and DH1317.9 neutralized various HIV-1 strains.
– Neutralized viruses included clade B, G, and recombinant strains.
Neutralization Mechanisms:
– Comparison of DH1317.4 with prototype bnAbs m66.6 and 2F5.
– DH1317.4 demonstrated similar neutralization profiles but with varying amino acid tolerances.
Effect of HIV-1 Diversity:
– Analysis of Env amino acid signatures by DH1317.4 compared with 2F5.
– Discussion on the impact of amino acid variability on neutralization resistance.
Impact on Vaccine Design:
– Exploration of HIV-1 neutralizing antibody signatures.
– Application of signatures in epitope-targeted vaccine design.
Sequence Diversity Analysis:
– Significance of sequence diversity in neutralization resistance.
– Effects of specific amino acid mutations on antibody-mediated neutralization.
Lipid Binding Role:
– Importance of virion lipid reactivity in MPER+ bnAbs.
– Role of CDRH3 hydrophobic loop in lipid binding and neutralization.
Overcoming Resistance Variants:
– Ability to overcome resistant variants by improved lipid binding.
– Discussion on overcoming roadblocks for neutralization of major HIV-1 clades.
Identification of CDRH1 Binding Motif:
– Crystallographic analysis revealed a CDRH1 binding motif (CDRH1 site 1) that interacts with lipid head groups.
– Utilization of CDRH3 was observed in binding to the hydrophobic acyl chain.
Analysis of CDRH1 Residues in DH1317 Lineage:
– Examination of DH1317 lineage and VH7-4-1-neutralizing antibody members showed similar putative lipid head group-binding CDRH1 sequences.
– Not all VH7-4-1 antibodies bound equally to liposomes containing phosphatidylglycerol (PG), which is a lipid ligand for the 4E10 bnAb.
Impact of Negatively Charged Residues:
– Antibodies with weaker PG-lipid binding had negatively charged residues near the CDRH1 lipid head group-binding site.
– These negatively charged residues could impede lipid binding due to charge hindrance.
Correlation between PG-Lipid Binding and Neutralization Potency:
– A significant correlation was observed between PG-lipid binding and HIV-1 strain W61D neutralization potency for the DH1317 lineage.
– Higher PG-lipid binding was associated with increased HIV W61D pseudovirus neutralization potency.
Lipid Insertion Propensity Scores:
– Computed lipid insertion propensity scores (ΔGwif) were associated with higher HIV W61D pseudovirus neutralization potency.
– Abs induced by HVTN-133 showed more favorable lipid insertion scores compared to nnAbs.
Binding to MPER Peptide-Liposomes:
– DH1317-neutralizing antibodies bound to MPER peptide-liposomes and could recognize MPER epitopes in the context of the lipid membrane.
– Different modes of binding were observed for DH1317.4, which neutralized tier 2 viruses, and DH1317.8, which neutralized tier 1 viruses.
Two-Step Binding Mode:
– DH1317.4 displayed a two-step binding mode similar to prototype MPER bnAbs that interact sequentially with lipids and MPER epitopes.
– DH1317.8, however, could not bind in the same two-step manner.
Role of Antibody Polyspecificity:
– The role of antibody polyspecificity and lipid reactivity in binding of broadly neutralizing anti-HIV-1 envelope antibodies to glycoprotein 41 membrane proximal envelope epitopes was investigated.
Stable Docking of Neutralizing Antibodies:
– Research by Stempel, Liao, and Haynes on gp41 antibodies 2f5 and 4e10 revealed membrane immersion depth dependency for stable docking.
– Membrane-proximal external region monoclonal antibodies play a critical role in neutralizing HIV-1.
Improbable Antibody Mutations:
– The development of broadly neutralizing antibodies (bnAbs) against HIV-1 faces challenges due to the necessity of rare but functional improbable mutations.
– Identification of improbable mutations like A51T, T99P, Y60S, and L72V in the DH1317 lineage was key for HIV-1 neutralization.
Functional Relevance of Improbable Mutations:
– Experimental results highlighted the importance of improbable mutations like A51T, T99P, Y60S, and L72V in enhancing neutralization potency against diverse HIV-1 strains.
– Combining specific improbable mutations significantly improved neutralization capabilities, demonstrating the impact of vaccination strategies on mutation selection.
Role of Lipid and Protein Epitope Binding:
– Distinct impacts of mutations A51T, T99P, Y60S, and L72V on lipid and protein binding were observed during the development of DH1317.4 bnAbs.
– MPER-liposome immunogen was critical in selecting for mutations facilitating optimal recognition of both MPER peptide and viral lipid binding.
Structural Analyses of Neutralizing Antibodies:
– Negative-stained electron microscopy studies on neutralizing B cell clonal lineages and prototype bnAbs provided insights into the structural basis of HIV-1 neutralization.
– Complexes with MPER-trimer encoding epitopes highlighted key residues involved in epitope recognition.
Interaction of HIV-1 envelope trimers with small-molecule viral entry inhibitor:
– Interactions between HIV-1 envelope trimers and small-molecule viral entry inhibitors were studied using Fab fragments of MPER-directed antibodies.
– The Fab-trimer complexes were visualized, revealing the binding of both prototypic bnAbs and HVTN 133 antibodies to the MPER epitope in a similar manner.
Disassembly of HIV envelope glycoprotein trimer immunogens:
– Antibodies elicited via immunization were observed to drive the disassembly of HIV envelope glycoprotein trimer immunogens.
– Considerable flexibility was observed in the binding of MPER-directed antibodies to the epitope.
Identification of cross-reactive HIV-1-neutralizing human monoclonal antibodies:
– Cross-reactive HIV-1-neutralizing human monoclonal antibodies were identified from a patient with 2F5-like antibodies.
– The most potent neutralizing antibody, DH1317.4, showed similar orientations in the presence of transmembrane and cytoplasmic domain regions.
Structural analysis of DH1317 lineage Abs:
– The cryo-EM reconstruction of the heterologous neutralizing antibody DH1317.4 in complex with a stabilized JRFL Env trimer revealed diverse views of the complex and differential mobility and flexibility between the Env ectodomain and the membrane-proximal regions.
– The cryo-EM reconstruction also demonstrated the compatibility of DH1317.4 binding to a pre-fusion closed HIV-1 Env SOSIP trimer.
HIV-1 envelope and MPER antibody structures in lipid assemblies:
– The structural basis for the epitope recognition of MPER-directed antibodies was studied through the co-crystallization with Fab fragments of VH7-4-1 neutralizing antibody lineages DH1317, DH1322, and DH1346.
– The study revealed that all three VH7-4-1 Abs recognized a similar helical conformation of the gp41 proximal MPER epitope, with buried interfaces on MPER ranging from 709 to 865 Å2.
Dynamic HIV-1 spike motion vulnerability to antibody attack:
– Cryo-EM reconstruction of DH1317.4 Fab bound to the HIV-1 Env trimer revealed its considerable interface with the transmembrane/micelle region, and its proximity to the gp41 glycan N611.
Common Features of Antibody Interactions with MPER:
– Examined structures show that neutralizing antibodies approach the MPER from similar angles and recognize the same face of the proximal MPER helix.
– The VH7-4-1 genes contribute to an almost identical set of interacting residues across the three antibodies.
Comparison with Previously Characterized Antibodies:
– Comparison of the modes of proximal MPER recognition of the VH7-4-1-using neutralizing antibodies against previously characterized antibodies in that region showed distinct patterns of interaction.
Helical Conformation and Antibody Recognition:
– DH570-bound MPER adopts an exclusively helical conformation, similar to VH7-4-1-using neutralizing antibodies.
– 2F5-bound MPER exclusively adopts an extended coil conformation.
Approach to MPER:
– DH570 approached from a similar direction as the VH7-4-1-using neutralizing antibodies, while m66 approached a face of the proximal MPER helix that was opposite.
Analysis of Contact BSA:
– VH7-4-1-using neutralizing antibodies mediated interactions with a nearly identical set of residues on gp41 and with similar degrees of buried surface per residue.
– MPER interface residues of DH570, m66, and 2F5 exhibited a pattern of interaction distinct from that observed for the VH7-4-1-using neutralizing antibodies.
Structural Analysis Insights:
– Disparate light chains and HCDR3 loops of DH1317.8, DH1322.1, and DH1346 did not alter their common modes of MPER recognition.
– X-ray crystallographic structural analysis revealed a shared mode of proximal MPER recognition that was permissive for use of diverse light chains and diverse heavy chain-encoded CDR3 loops.
Structural Interaction with MPER:
– Structural studies show interaction of MPER-directed antibodies with Env epitope at different resolution scales.
– Antibodies interacted with residues on MPER distinct from those bound by other neutralizing antibodies.
Lineage Tracing of MPER+ Neutralizing B Cells:
– 24 vaccine-induced MPER+ neutralizing B cell clones detected post-3rd immunization in two vaccine responders.
– Clonal relatives for 20 of these clones found over time via NGS.
Vaccine-Induced BNAb Lineages:
– Vaccine containing HIV-1 gp41 MPER peptide-liposomes induced polyclonal MPER-directed B cell repertoire responses.
– Most potent B cell clonal lineage demonstrated greatest neutralization breadth for clade B.
Implications of the Study:
– Reformulation of the MPER peptide-liposome without PEG may increase neutralizing antibody affinity.
– Vaccine-induced lipid-reactive antibodies not controlled by tolerance to lipids, suggesting potential for increased neutralization breadth and potency.
MPER Antibody Development:
– Full maturation of MPER bnAbs is limited by immune tolerance.
– Performance of additional boosts may enhance neutralizing antibody affinity and broaden neutralization potency.
GP41 Neutralizing B Cell Lineages:
– Initiation of immune tolerance-controlled HIV gp41 neutralizing B cell lineages observed in MPER unmutated ancestor and mature bnAb knockin mice.
– Complex tolerance mechanisms and cross-reactivities associated with gp41 and lipids influence the production of broad neutralizing antibodies.
B Cell Clonal Lineages:
– MPER-directed antibodies induced by the vaccine interacted with Env epitopes.
– Vaccine responses suggest the potential for developing effective MPER bnAb lineages.
Vaccine Efficacy:
– Vaccine-induced lipid-reactive antibodies hint at overcoming tolerance mechanisms.
– MPER peptide-liposome design targeting unmutated ancestors could lead to the development of effective bnAbs.
Selection of Neutralizing Antibodies:
– MPER+ antibodies selected by the MPER peptide-liposome utilized the VH2-5 gene but did not have HCDR3s longer than 11 aa.
– VH7-4-1 heterologous neutralizing antibodies were positively selected by the MPER peptide-liposome.
Implications for Vaccine Design:
– Insights were provided into the sequence of events when MPER bnAbs develop.
– New immunogens are being designed to boost MPER bnAbs with increased breadth and potency.
Clinical Limitations:
– Limitation due to interruption of the HVTN 133 trial and limited participation in three immunizations.
– Some individuals are predicted to make VH7-4-1 utilizing MPER bnAb lineages.
Polyclonal Neutralizing Response:
– The MPER peptide-liposomes induced a polyclonal neutralizing antibody response utilizing multiple heavy chain genes.
Roadmap for Boost Immunogens:
– Env resistance signatures identified provide direction for designing boost immunogens with enhanced breadth.
– Proximal and distal MPER-targeting antibodies may need to be induced to address clade specificity.
Feasibility of Vaccine Development:
– Vaccine-associated functional mutations in bnAb B cell lineages were observed after only 3 immunizations.
– Important insights for the design and feasibility of HIV-1 vaccine development to induce bnAbs.
Clinical Trial and Antibody Response:
– Two high responders with VH7-4-1∗02 allele made VH7-4-1-neutralizing antibody B cell lineages.
– MPER peptide-liposomes induced varied heavy chain genes in the antibody response.
Summary of Core Studies:
– Roles of prototype bnAbs and resistance signatures in designing boost immunogens to enhance responses.
– Importance of inducing diverse MPER-targeted antibodies for increased HIV-1 vaccine efficacy.
Summary Point 1:
– Trials of neutralizing antibodies to prevent HIV-1 acquisition are a key focus in current research.
– Several studies have highlighted the differential reactivity of germ line allelic variants of broadly neutralizing HIV-1 antibodies.
Summary Point 2:
– Initiation of immune tolerance-controlled HIV gp41 neutralizing B cell lineages has been investigated to understand immune response mechanisms.
– The reactivity of germ line allelic variants to specific conformations of the virus has implications in antibody development.
Summary Point 3:
– Altering specific epitope peptides like MPER.03 and MPER656 could provide insights into enhancing antibody responses.
– Studies have identified critical peptides and fusion intermediate conformations as potential targets for antibody development.
Summary Point 4:
– Use of peptide-liposome immunogens like MPER656 has shown promise in inducing specific immune responses.
– Identification of antigenic determinants like SP62 provides further understanding of potential vaccine candidates.
Summary Point 5:
– The deployment of critical commercial assays and advanced sequencing kits has facilitated detailed immune response analysis.
– Deposited data and experimental models play a crucial role in deciphering immune interactions and vaccine design.
Summary Point 6:
– Structural data from Cryo-EM and X-ray crystal structures provide insights into the interaction between antibodies and viral proteins.
– Advanced software tools and algorithms enhance the analysis and interpretation of immunological data.
Summary Point 7:
– Cell lines like Expi293F and HEK 293T are commonly used for vaccine development and antibody production.
– Sophisticated analytical pipelines like ARMADiLLO and MPEX version are crucial in antibody development studies.
Summary Point 8:
– The diversity of rhesus macaque immunoglobulin loci and antibody mutations contribute to understanding antibody development.
– Functional relevance of improbable antibody mutations is being explored for the development of broadly neutralizing antibodies against HIV.
VDJ Sequencing Analysis:
– The paper utilizes a custom VDJ sequencing analysis tool for its research.
– The analysis involves the use of the AnalyzeAlign tool from Los Alamos HIV Databases and uses the custom script available at GitHub.
SciPy:
– The paper makes use of Scipy 1.0 for fundamental algorithms in scientific computing in Python.
– The tool provides essential algorithms and methodologies for scientific computations.
Membrane Protein Explorer v3.3.0:
– The Membrane Protein Explorer v3.3.0 is referenced in the paper for membrane protein exploration.
– The tool is used for exploring membrane proteins and understanding their properties.
R Function Stat_corr from Package ggpubr:
– The paper utilizes the R function stat_corr from the package ggpubr for statistical analysis.
– The function is used for statistical calculations and visualizations in R.
Resource Availability:
– The lead contact, Wilton B. Williams, will fulfill requests for resources and reagents.
– Data and code availability are outlined for additional data analyses and custom scripts used in the manuscript.
Vaccine Participants:
– The HVTN 133 clinical trial had 24 participants enrolled, including 20 vaccine and 4 placebo recipients.
– The trial was halted due to safety concerns after some participants received the immunizations.
Ethical Oversight:
– The trial’s ethical oversight and monitoring were conducted through standard procedures and boards at various institutions.
– Written informed consent was obtained from each participant prior to enrollment.
HVTN 133 Primary and Secondary Outcomes:
– The primary and secondary objectives and endpoints of the HVTN 133 clinical trial are outlined in the publication.
– They include evaluating the safety, tolerability, and immune responses of the vaccine regimen.
Initiation of immune tolerance-controlled hiv gp41 neutralizing B cell lineages:
– High-throughput isolation of single human B cells
– Expression as monoclonal antibodies
Cryopreserved PBMCs and cell labeling:
– Optimized fluorochrome-mAb conjugates used for labeling
– Memory B cells sorted and labeled with antigen baits
Production of fluorophore-conjugated MPER peptide:
– Conjugation process with VB515 and AF647 fluorophores
– Confirmation of binding to antibody-coated beads
PCR isolation of antibodies from antigen-specific B cell sorts:
– Single B cells sorted into plates with lysis buffer
– Isolation of VHDJH and VLJL segments by single-cell PCR
Stabilized hiv-1 envelope immunization:
– Inducing neutralizing antibodies to the CD4bs
– Protection against mucosal infection in macaques
Flow cytometry-based sorting of single B cells:
– Sorted B cells stored at -80
– Isolation of human VHDJH and VLJL segments by single-cell PCR
Isolation of Human Anti-HIV Antibodies:
– Antibody sequences were analyzed using a custom-built bioinformatics pipeline for base-calling, contig assembly, and quality trimming.
– The heavy and light chain variable regions for the antibodies were provided in Mendeley Data.
Recombinant Antibody Production:
– Amplified antibody heavy and light chain genes were used to generate linear expression cassettes.
– Recombinant antibodies were generated in large quantities using commercially-obtained plasmids and Expi293F cells.
Stabilized HIV-1 Envelope Immunization:
– Stabilized HIV-1 envelope immunization induced neutralizing antibodies to the CD4bs and protected macaques against mucosal infection.
– The study reported the isolation of immunoglobulin genes from single human B cells and their expression as monoclonal antibodies.
Generation and Testing of Recombinant Antibodies:
– From the initial binding screen, 87 MPER+ antibodies were identified.
– 83 representative recombinant monoclonal antibodies were expressed and tested for appropriate heavy and/or light chain protein expression.
Site-Directed Mutagenesis:
– Fifty nanograms of antibody heavy or light chain plasmid was mutated using the QuikChange Lightning Multi Site-Directed Mutagenesis Kit.
– Mutated plasmids were used for transient transfection of Expi293F cells using the Expifectamine transfection system.
VDJ Sequencing of Single B Cells:
– Single Cell VDJ library construction was performed on 10X Chromium Controller using the Chromium Next GEM Single Cell 5′ Kit v2.
– VDJ libraries were sequenced on the Illumina NovaSeq 6000 platform with Novaseq S4 Reagent kit.
VDJ Analysis:
– Illumina NGS generated BCR sequencing data was processed using the Cell Ranger single cell gene expression software.
– Contigs assembled by Cell Ranger were analyzed to provide insights into the immunogenetics of the antibodies.
Immunogenetics of MPER+ Antibodies:
– The Ig genes used by MPER+ Abs in the HVTN 133 vaccinees were reported from the antigen-naïve total BCR repertoires.
– Immunogenetics of two MPER+ Abs at baseline from 2/5 vaccinees studied were not shown (133-30 and 133-23).
Genome Assemblies:
– The study analyzed the structure and diversity of the rhesus macaque immunoglobulin loci through multiple De Novo Genome Assemblies.
– It used the default human Ig library to determine B cell immunogenetics and clonality.
Antibody Categories:
– The research identified fab-dimerized glycan-reactive antibodies as a structural category of natural antibodies.
– The softwares used for computational analysis of B cell receptor sequencing included MPEX, ANARCI, Cloanalyst, Figtree, ARMADiLLO, and Cell Ranger.
Sequencing Analysis:
– Next generation deep-sequencing and analysis of antibody genes was performed using Illumina NextSeq sequencing and the Archer Immunoverse BCR IGH/K/L kit.
– Quality filtered sequences were used for segment testing and reconstruction of clonal lineage trees using the Cloanalyst software.
B-cell Clonal Lineage:
– The clonal lineage of B-cells was reconstructed and statistical inference of unobserved ancestors was performed.
– Immunogenetics information of human antibody sequences were assigned using Cloanalyst’s default libraries of human immunoglobulin genes.
Antibody Binding:
– The indirect binding ELISA method was used to measure antibody binding.
– ELISA binding data were collected by Spectramax Plus384 plate reader and analyzed using Softmax Pro version 5.3.
Polyreactivity Binding Assays:
– MAb reactivity to nine autoantigens was measured using the AtheNA Multi-Lyte ANA kit.
– The reactivity to cardiolipin was measured using the Quanta Lite ACA IgG III kit.
Neutralization Assays:
– Neutralizing antibodies were measured in either TZM-bl cells or TZM-bl/FcγRI cells, as described in the literature.
Neutralization Assays and Results:
– Virus doses were incubated with serum or mAbs in 96-well plates.
– Neutralization titers were determined by measuring luminescence.
Clonal Lineages and Neutralization:
– 49 MPER+ neutralizing antibodies formed 24 clonal lineages.
– Geometric mean IC50 neutralization titers were calculated for various HIV-1 strains.
DH1317.4 bnAb Testing:
– DH1317.4 bnAb was tested against a panel of 197 HIV-1 Env pseudoviruses.
– Results were analyzed for neutralization efficacy.
Env Neutralization Signature Analyses:
– DH1317.4 and DH1317.9 signatures were analyzed.
– Robust signature sites were identified for epitope-targeted vaccine design.
Binary Phenotypes and Signature Sites:
– Binary phenotypes of sensitivity or resistance were determined for DH1317.4 and DH1317.9.
– Robust signature sites were identified using specific criteria.
Inter-Subtype Variation Analysis:
– Inter-subtype variation at key signature sites was analyzed.
– Comparison of neutralization profiles between bnAbs was conducted using statistical tests.
Software and Analysis Tools:
– Promega GloMax Navigator was used for data collection.
– LabKey Server NAb Tool was used for neutralization data analysis.
Comparison of Neutralization Profiles:
– Linear regression and Fisher’s exact test were used for comparing neutralization profiles.
– Analysis included comparison of signature sites and clade effects.
Scipy 1.0: Fundamental Algorithms for Scientific Computing in Python:
– Scipy 1.0 provides fundamental algorithms for scientific computing in Python.
– It is a valuable resource for scientific researchers using Python.
Neutralization Titer Biomarker for Antibody-Mediated Prevention of HIV-1 Acquisition:
– The study focuses on the neutralization titer biomarker for antibody-mediated prevention of HIV-1 acquisition.
– It discusses the significant findings related to HIV prevention.
Antibody Binding to Binary Phospholipids:
– The research presents the methodology of antibody binding to binary phospholipids.
– It involves the preparation and binding measurements of PC-PG binary lipids.
Surface Plasmon Resonance (SPR) for Antibody Binding:
– The study utilizes surface plasmon resonance (SPR) for antibody binding.
– The method involves capturing lipids, injecting mAb, and performing analysis using BiaEvaluation Software.
DH1317 Ab Lineage Binding to Phosphatidylglycerol (PG)-Containing Lipids:
– The research explores the DH1317 Ab lineage binding to POPC:DOPG (25:75) liposomes using SPR.
– It includes the measurement of binding responses in RU normalized to control surface and capture level of liposomes.
Lipid Insertion Propensity Scores:
– The study calculates lipid insertion propensity scores using the hydropathy analysis tool MPEx.
– It involves the use of ΔGwif scores based on free energy of binding and custom R scripts for computation.
Antibody and Fab Binding and Titrations Against MPER Liposome Immunogen:
– The research discusses the binding of antibodies to the MPER656 peptide-liposome immunogen and the corresponding titrations using BLI.
– It includes the use of control reference mAbs and the analysis performed using ForteBio Data Analysis 10.0 software.
Conclusion:
– The summarized research covers significant findings in the fields of scientific computing, HIV prevention, antibody binding, and lipid insertion propensity.
– It provides valuable insights into the methodologies and results of the studies.
F(ab) Preparation:
– Performed using a modified protocol previously described
– Samples dialyzed into 20mM sodium phosphate, 10mM EDTA, pH 7.0, and then concentrated to 20mg/ml
Quality Assessment of F(ab):
– Measured via SDS-PAGE and size exclusion chromatography (SEC)
– F(ab) peaks were analyzed with the system’s Unicorn 7.6.0 software
Titrations of F(ab) to SP62 Peptide and Mutants:
– Affinities of F(ab)s to SP62 peptide and alanine-substituted mutants measured through SPR using a BIAcore S200 instrument
– Curve fitting of results performed through BIAcore S200 evaluation software
Protein Expression and Purification:
– Plasmid constructs prepared from the HIV-1 JRFL Env protein sequence
– Env expressed in different forms and purified using multiple steps
Fab Purification and Characterization:
– Fabs DH1317.4, DH1322.1, and DH1346 were purified and characterized
– Fab complexes were prepared with specific peptides at 3-fold molar excess
Protein Crystallization Process:
– DH1317.8 Fab-SP62 peptide complex crystals obtained in specific conditions
– DH1322.1 Fab crystals obtained in PEG 1500 and SPG buffer pH 8.5
X-ray Crystallography Data Collection:
– Diffraction data collected at the SERCAT and Stanford Synchrotron Radiation Lightsource
– Datasets processed using HKL-2000 or XDS for structure determination
Molecular Replacement and Structure Refinement:
– Structures solved by molecular replacement using PHASER
– Refinement carried out using PHENIX with manual model building in Coot
Statistical Correlations:
– Statistical correlations between interface residue BSA of shared MPER epitope residues were tested using VH7-4-1-using nAbs.
– Results showed varying correlation strengths among VH7-4-1 nAbs and other antibodies.
Negative Stain Electron Microscopy:
– Complex formation process detailed with incubation and sample preparation steps.
– Grid preparation, staining, and imaging parameters for electron microscopy analysis were described.
Cryo-Electron Microscopy:
– Description of sample preparation with DH1317.4 Fab addition and plunge freezing process.
– Data collection details using a FEI Titan Krios electron microscope and processing steps in cryoSparc.
Reagent Authentication:
– Use of authenticated cell lines like Expi293F and TZM-bl with certification.
– Positive control antibodies applied in neutralization assays for authenticity verification.
Quantification and Statistical Analysis:
– GraphPad Prism v9.0 utilized for generating graphs and statistical comparisons.
– Methods included Mann-Whitney test, linear regression, Fisher’s exact test, and graphical representations.
Acknowledgments:
– Work supported by various grants including from NIH, NIAID, and Bill & Melinda Gates Foundation.
– Appreciation expressed to individuals and institutions for specific contributions and support.
Research Methods:
– Neutralization assays and signature correlation analyses were conducted by A.E., K. Wagh, and B.K.
– NSEM was performed by R.J.E. and K.M., while flow sorting was carried out by D.W.C., M.M., A.A.-A., J.H., and X.L.
Laboratory Work:
– Plasmid production was handled by F.C. and N.J., BCR sequencing by I.M., T.E., and Y.C., and antibody assays by R.P., M. Barr, A.F., K.A., and P.P.
Protein Production:
– Protein production and cryo-EM were managed by P.A., S.S., X.H., J.L., S.F., R.P., K.J., and K.O.S.
Specialized Analyses:
– X-ray crystallography was conducted by A.N., B.M.J., and A.A., while computational analysis was performed by M. Berry, H.K., E.V.I, and K. Wiehe.
– Vaccine immunogen work was carried out by C.B.F., with HVTN lab analyses by K.W.C. and M.J.M.
Patents:
– B.F.H. and S.M.A. hold US patents 9402917, 9402893, 9717789, and 10588960, with a patent application under 63/540482.
– B.F.H., S.M.A., and B.K. have US patent 10076567, and B.F.H. and K.O.S. have patent applications under PCT/US2023/077677 and PCT/US2023/077686. C.B.F. holds patents on PEGylated liposomes.
References:
– Important references include studies on HIV vaccine efficacy trials, broadly neutralizing antibodies, and strategies for inducing neutralizing antibodies to HIV-1.
Potent Neutralizing Antibodies:
– Human monoclonal antibodies have been developed that demonstrate potent cross-clade neutralizing activity against a novel epitope on gp41 of human immunodeficiency virus type 1.
– Several broadly neutralizing antibodies with potent and cross-reactive HIV-1 neutralizing activity have been identified from memory B cells and plasma, targeting different epitopes on the HIV-1 glycoprotein gp41 and demonstrating broad neutralization.
Antibody Specificity:
– Some broadly neutralizing antibodies are polyspecific and show reactivity to lipids, demonstrating the role of antibody polyspecificity and lipid reactivity in binding to glycoprotein 41 membrane proximal envelope epitopes.
– Common tolerance mechanisms limit the production of broadly neutralizing antibodies 2f5 and 4e10, as distinct cross-reactivities associated with gp41 and lipids play a role in their production.
Mechanisms of Neutralization:
– An integral component of the epitope of a broadly neutralizing antibody was identified to be lipid, indicating the role of lipid in neutralization by certain broadly neutralizing antibodies.
– Studies have shown that the high-affinity immunoglobulin receptor FcγRI can potentiate HIV-1 neutralization via antibodies against the gp41 N-heptad repeat, providing insights into the mechanisms of neutralization.
Generation of Antibodies:
– The generation of human monoclonal antibodies against HIV-1 proteins has been achieved through various techniques such as electrofusion and Epstein-Barr virus transformation for peripheral blood lymphocyte immortalization.
– The initiation of immune tolerance-controlled HIV gp41 neutralizing B cell lineages has been studied to understand the mechanisms involved in the generation of neutralizing antibodies.
Co-evolution of Broadly Neutralizing HIV-1 Antibody and Founder Virus:
– Study by Roskin et al. in Nature (2013) explores co-evolution of HIV-1 antibody and virus.
– Highlights interaction dynamics essential for understanding immune responses.
Induction of Glycan-Dependent Neutralizing Antibodies:
– Research by Bonsignori et al. in Sci. Transl. Med. (2017) examines staged induction of glycan-dependent antibodies.
– Insights into potential vaccine development strategies.
Maturation Pathway of Broad HIV-1 Neutralizer Antibody:
– Investigation by Bonsignori et al. in Cell (2016) unravels maturation pathway of CD4-mimic antibody.
– Critical for understanding antibody evolution.
Broadly Neutralizing Antibodies in Elite Neutralizers:
– Landais and Moore in Retrovirology (2018) analyze development of broadly neutralizing antibodies in elite neutralizers.
– Provides insights into natural immune responses.
B-Cell-Lineage Immunogen Design for HIV-1 Vaccine:
– Haynes et al. in Nat. Biotechnol. (2012) discuss B-cell-lineage immunogen design with HIV-1 as a case study.
– Implications for vaccine development strategies.
Induction of Antibodies Recognizing HIV-1 Fusion Intermediate:
– Study by Dennison et al. in PLoS One (2011) sheds light on inducing antibodies recognizing fusion-intermediate conformation of HIV-1.
– Relevance for vaccine design against HIV-1 entry.
Docking of Neutralizing Antibodies on HIV-1 gp41:
– Research by Dennison et al. in J. Virol. (2009) investigates stable docking of neutralizing antibodies on gp41.
– Key insights into antibody-antigen interaction.
Relevance of Antibody Mutations for Broad HIV Neutralization:
– Wiehe et al. in Cell Host Microbe (2018) study functional relevance of improbable antibody mutations for HIV broadly neutralizing antibody development.
– Significance for understanding antibody evolution.
Identification of near-pan-neutralizing antibodies against HIV-1:
– Plasma humoral responses were deconvoluted to identify near-pan-neutralizing antibodies against HIV-1.
– The study was published in the journal Cell in 2018.
HIV-1 neutralizing antibody signatures for vaccine design:
– Research focused on understanding HIV-1 neutralizing antibody signatures for the development of epitope-targeted vaccines.
– The work was published in Cell Host Microbe in 2019.
Antigenicity of HIV-1 envelope trimers with a viral entry inhibitor:
– The antigenicity and immunogenicity of HIV-1 envelope trimers complexed to a small-molecule viral entry inhibitor were studied.
– Results were published in the Journal of Virology in 2020.
Immunization-induced disassembly of HIV envelope glycoprotein trimer immunogens:
– Research revealed that antibodies elicited through immunization can drive the disassembly of HIV envelope glycoprotein trimer immunogens.
– The study was published in Science Advances in 2021.
Structural analysis of HIV-1 spike motion vulnerability:
– Dynamic motion of the HIV-1 spike creates vulnerability for antibody attack on its membrane-bound tripod.
– The findings were published in Nature Communications in 2022.
Mechanism of HIV-1 neutralization by 2f5-like antibodies:
– The structural basis of HIV-1 neutralization by 2f5-like antibodies m66 and m66.6 was elucidated.
– The study was published in the Journal of Virology in 2014.
Autoreactivity in broadly reactive HIV-1 neutralizing antibodies:
– The study investigated how autoreactivity in broadly reactive neutralizing antibodies induces immunologic tolerance against HIV-1.
– Results were published in the Proceedings of the National Academy of Sciences USA in 2010.
Diversity of rhesus macaque immunoglobulin loci:
– Structural and diversity analysis of the rhesus macaque immunoglobulin loci was performed through multiple de novo genome assemblies.
– Research findings were published in Frontiers in Immunology in 2017.
Fab-dimerized glycan-reactive antibodies:
– Structural category of natural antibodies
– Novel research in antibody structure
Reconstructing a B-cell clonal lineage:
– Statistical inference of unobserved ancestors
– Mutation, selection, and affinity maturation
Measuring HIV neutralization:
– Usage of luciferase reporter gene assay
– Relevance in HIV prevention
Experimentally determined hydrophobicity scale for proteins at membrane interfaces:
– Research on protein hydrophobicity
– Relevance in membrane interactions
Anarci: antigen receptor numbering and receptor classification:
– A tool for antigen receptor numbering
– Classification of receptors
Electron-microscopy-based epitope mapping:
– Defining specificities of polyclonal antibodies
– Relevance in HIV-1 bg505 envelope trimer immunization
Improving the immunogenicity of native-like HIV-1 envelope trimers:
– Enhancing immunogenicity of envelope trimers
– Relevance in HIV research
New tools for automated high-resolution cryo-EM structure determination:
– Advancements in cryo-EM structure determination
– Automation of high-resolution processes
MPER+ Antibody Response:
– The HVTN 133 clinical trial elicited a diverse MPER+ antibody response.
– The neutralization breadth profile of vaccine-induced antibodies was analyzed.
Immunogenetics Analysis:
– The immunogenetics of MPER+ antibody response were studied in relation to Figure 1.
– Neutralization breadth of vaccine-induced DH1317 bnAb was also examined.
Neutralization Mapping:
– Mapping of MPER+ NAbs to proximal bnAb epitopes was performed.
– The neutralization breadth of vaccine-induced DH1317 bnAb was related to Figures 2 and 3.
Lipid Reactivity and Mutation Analysis:
– Lipid reactivity profiles of DH1317 lineage antibodies were characterized.
– Characterization of improbable mutations in DH1317 lineage antibodies was also elaborated.
Structural Characterization:
– Structural analysis of DH1317 lineage Abs was conducted, related to Figure 3.
– Structural comparison of antibody recognition of proximal gp41 MPER was also performed.