RESUMO
Anti-HIV-1 envelope broadly neutralizing monoclonal antibodies (bNAbs) isolated from memory B cells may not fully represent HIV-1-neutralizing profiles measured in plasma. Accordingly, we characterized near-pan-neutralizing antibodies extracted directly from the plasma of two "elite neutralizers." Circulating anti-gp120 polyclonal antibodies were deconvoluted using proteomics to guide lineage analysis of bone marrow plasma cells. In both subjects, a single lineage of anti-CD4-binding site (CD4bs) antibodies explained the plasma-neutralizing activity. Importantly, members of these lineages potently neutralized 89%-100% of a multi-tier 117 pseudovirus panel, closely matching the specificity and breadth of the circulating antibodies. X-ray crystallographic analysis of one monoclonal, N49P7, suggested a unique ability to bypass the CD4bs Phe43 cavity, while reaching deep into highly conserved residues of Layer 3 of the gp120 inner domain, likely explaining its extreme potency and breadth. Further direct analyses of plasma anti-HIV-1 bNAbs should provide new insights for developing antibody-based antiviral agents and vaccines.
Assuntos
Anticorpos Neutralizantes/imunologia , Proteína gp120 do Envelope de HIV/imunologia , HIV-1/metabolismo , Sequência de Aminoácidos , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/química , Sítios de Ligação , Antígenos CD4/química , Antígenos CD4/metabolismo , Cristalografia por Raios X , Anticorpos Anti-HIV/sangue , Anticorpos Anti-HIV/imunologia , Proteína gp120 do Envelope de HIV/química , Proteína gp120 do Envelope de HIV/metabolismo , HIV-1/genética , Humanos , Simulação de Dinâmica Molecular , Ligação Proteica , Estrutura Terciária de Proteína , RNA Viral/sangue , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/imunologiaRESUMO
Antibodies with ontogenies from VH1-2 or VH1-46-germline genes dominate the broadly neutralizing response against the CD4-binding site (CD4bs) on HIV-1. Here, we define with longitudinal sampling from time-of-infection the development of a VH1-46-derived antibody lineage that matured to neutralize 90% of HIV-1 isolates. Structures of lineage antibodies CH235 (week 41 from time-of-infection, 18% breadth), CH235.9 (week 152, 77%), and CH235.12 (week 323, 90%) demonstrated the maturing epitope to focus on the conformationally invariant portion of the CD4bs. Similarities between CH235 lineage and five unrelated CD4bs lineages in epitope focusing, length-of-time to develop breadth, and extraordinary level of somatic hypermutation suggested commonalities in maturation among all CD4bs antibodies. Fortunately, the required CH235-lineage hypermutation appeared substantially guided by the intrinsic mutability of the VH1-46 gene, which closely resembled VH1-2. We integrated our CH235-lineage findings with a second broadly neutralizing lineage and HIV-1 co-evolution to suggest a vaccination strategy for inducing both lineages.
Assuntos
Vacinas contra a AIDS/imunologia , Anticorpos Neutralizantes/imunologia , Anticorpos Anti-HIV/imunologia , Infecções por HIV/imunologia , Sequência de Aminoácidos , Anticorpos Neutralizantes/química , Linfócitos B/imunologia , Anticorpos Anti-HIV/química , Proteína gp120 do Envelope de HIV/imunologia , Infecções por HIV/prevenção & controle , HIV-1/imunologia , Humanos , Modelos Moleculares , Dados de Sequência Molecular , Alinhamento de SequênciaRESUMO
HIV-1 broadly neutralizing antibodies (bnAbs) develop in a subset of infected adults and exhibit high levels of somatic hypermutation (SHM) due to years of affinity maturation. There is no precedent for eliciting highly mutated antibodies by vaccination, nor is it practical to wait years for a desired response. Infants develop broad responses early, which may suggest a more direct path to generating bnAbs. Here, we isolated ten neutralizing antibodies (nAbs) contributing to plasma breadth of an infant at â¼1 year post-infection, including one with cross-clade breadth. The nAbs bind to envelope trimer from the transmitted virus, suggesting that this interaction may have initiated development of the infant nAbs. The infant cross-clade bnAb targets the N332 supersite on envelope but, unlike adult bnAbs targeting this site, lacks indels and has low SHM. The identification of this infant bnAb illustrates that HIV-1-specific neutralization breadth can develop without prolonged affinity maturation and extensive SHM.
Assuntos
Anticorpos Neutralizantes/genética , Anticorpos Anti-HIV/genética , Hipermutação Somática de Imunoglobulina , Adulto , Anticorpos Neutralizantes/imunologia , Epitopos , Anticorpos Anti-HIV/sangue , Anticorpos Anti-HIV/imunologia , Proteína gp120 do Envelope de HIV/imunologia , Infecções por HIV/sangue , Infecções por HIV/imunologia , Humanos , Lactente , Leucócitos MononuclearesRESUMO
Broadly neutralizing antibodies (bNAbs) against the HIV-1 envelope glycoprotein (Env) suppress viremia in animal models of HIV-1 and humans. To achieve potent activity without the emergence of viral escape mutants, co-administration of different bNAbs is necessary to target distinct epitopes essential for viral fitness. Here, we report the development of bispecific anti-Env neutralizing antibodies (biNAbs) with potent activity. Synergistic activity of biNAbs was achieved by combining an engineered hinge domain of IgG3 to increase Fab domain flexibility necessary for hetero-bivalent binding to the Env trimer while retaining the functional properties of the IgG1-Fc. Compared to unmodified biNAbs, hinge domain variants exhibited substantially improved neutralization activity, with particular combinations showing evidence of synergistic neutralization potency in vitro and enhanced in vivo therapeutic activity in HIV-1-infected humanized mice. These findings suggest innovative strategies for generating biNAbs with enhanced neutralization breadth and potency, representing ideal candidate molecules for the control of HIV-1 infection.
Assuntos
Anticorpos Biespecíficos/química , Proteína gp120 do Envelope de HIV/imunologia , HIV-1/imunologia , Animais , Anticorpos Biespecíficos/imunologia , Anticorpos Neutralizantes/química , Anticorpos Neutralizantes/imunologia , Epitopos , Proteína gp120 do Envelope de HIV/química , Infecções por HIV/prevenção & controle , Infecções por HIV/terapia , Humanos , Imunização Passiva , Fragmentos Fab das Imunoglobulinas/química , Fragmentos Fab das Imunoglobulinas/imunologia , Imunoglobulina G/química , Imunoglobulina G/imunologia , CamundongosRESUMO
Generation of potent antibodies by a mutation-selection process called affinity maturation is a key component of effective immune responses. Antibodies that protect against highly mutable pathogens must neutralize diverse strains. Developing effective immunization strategies to drive their evolution requires understanding how affinity maturation happens in an environment where variants of the same antigen are present. We present an in silico model of affinity maturation driven by antigen variants which reveals that induction of cross-reactive antibodies often occurs with low probability because conflicting selection forces, imposed by different antigen variants, can frustrate affinity maturation. We describe how variables such as temporal pattern of antigen administration influence the outcome of this frustrated evolutionary process. Our calculations predict, and experiments in mice with variant gp120 constructs of the HIV envelope protein confirm, that sequential immunization with antigen variants is preferred over a cocktail for induction of cross-reactive antibodies focused on the shared CD4 binding site epitope.
Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Reações Cruzadas , Proteína gp120 do Envelope de HIV/imunologia , Animais , Variação Antigênica , Linfócitos B/imunologia , Simulação por Computador , Proteína gp120 do Envelope de HIV/genética , HIV-1/imunologia , CamundongosRESUMO
Antibodies developed during HIV-1 infection lose efficacy as the viral spike mutates. We postulated that anti-HIV-1 antibodies primarily bind monovalently because HIV's low spike density impedes bivalent binding through inter-spike crosslinking, and the spike structure prohibits bivalent binding through intra-spike crosslinking. Monovalent binding reduces avidity and potency, thus expanding the range of mutations permitting antibody evasion. To test this idea, we engineered antibody-based molecules capable of bivalent binding through intra-spike crosslinking. We used DNA as a "molecular ruler" to measure intra-epitope distances on virion-bound spikes and construct intra-spike crosslinking molecules. Optimal bivalent reagents exhibited up to 2.5 orders of magnitude increased potency (>100-fold average increases across virus panels) and identified conformational states of virion-bound spikes. The demonstration that intra-spike crosslinking lowers the concentration of antibodies required for neutralization supports the hypothesis that low spike densities facilitate antibody evasion and the use of molecules capable of intra-spike crosslinking for therapy or passive protection.
Assuntos
Anticorpos Neutralizantes/química , Anticorpos Anti-HIV/química , HIV-1 , Fragmentos Fab das Imunoglobulinas/química , Imunoglobulina G/química , Anticorpos Neutralizantes/imunologia , Reagentes de Ligações Cruzadas/metabolismo , Cristalografia por Raios X , Epitopos , Anticorpos Anti-HIV/imunologia , Proteína gp120 do Envelope de HIV/imunologia , Imunoglobulina G/imunologia , Engenharia de ProteínasRESUMO
The site on the HIV-1 gp120 glycoprotein that binds the CD4 receptor is recognized by broadly reactive antibodies, several of which neutralize over 90% of HIV-1 strains. To understand how antibodies achieve such neutralization, we isolated CD4-binding-site (CD4bs) antibodies and analyzed 16 co-crystal structures -8 determined here- of CD4bs antibodies from 14 donors. The 16 antibodies segregated by recognition mode and developmental ontogeny into two types: CDR H3-dominated and VH-gene-restricted. Both could achieve greater than 80% neutralization breadth, and both could develop in the same donor. Although paratope chemistries differed, all 16 gp120-CD4bs antibody complexes showed geometric similarity, with antibody-neutralization breadth correlating with antibody-angle of approach relative to the most effective antibody of each type. The repertoire for effective recognition of the CD4 supersite thus comprises antibodies with distinct paratopes arrayed about two optimal geometric orientations, one achieved by CDR H3 ontogenies and the other achieved by VH-gene-restricted ontogenies.
Assuntos
Anticorpos Neutralizantes/química , Anticorpos Antivirais/química , Proteína gp120 do Envelope de HIV/química , Proteína gp120 do Envelope de HIV/metabolismo , HIV-1/fisiologia , Sequência de Aminoácidos , Anticorpos Neutralizantes/metabolismo , Anticorpos Antivirais/metabolismo , Linfócitos B/imunologia , Antígenos CD4/metabolismo , Regiões Determinantes de Complementaridade , Epitopos de Linfócito B , Proteína gp120 do Envelope de HIV/imunologia , Humanos , Modelos Moleculares , Dados de Sequência Molecular , Alinhamento de SequênciaRESUMO
The HIV envelope glycoprotein (Env) is densely covered with self-glycans that should help shield it from recognition by the human immune system. Here, we examine how a particularly potent family of broadly neutralizing antibodies (Abs) has evolved common and distinct structural features to counter the glycan shield and interact with both glycan and protein components of HIV Env. The inferred germline antibody already harbors potential binding pockets for a glycan and a short protein segment. Affinity maturation then leads to divergent evolutionary branches that either focus on a single glycan and protein segment (e.g., Ab PGT124) or engage multiple glycans (e.g., Abs PGT121-123). Furthermore, other surrounding glycans are avoided by selecting an appropriate initial antibody shape that prevents steric hindrance. Such molecular recognition lessons are important for engineering proteins that can recognize or accommodate glycans.
Assuntos
Anticorpos Neutralizantes/química , Anticorpos Anti-HIV/química , Proteína gp120 do Envelope de HIV/imunologia , HIV-1/química , HIV-1/imunologia , Vacinas contra a AIDS/química , Vacinas contra a AIDS/imunologia , Sequência de Aminoácidos , Anticorpos Neutralizantes/metabolismo , Anticorpos Anti-HIV/metabolismo , Proteína gp120 do Envelope de HIV/química , Modelos Moleculares , Dados de Sequência Molecular , Alinhamento de SequênciaRESUMO
The VH1-2 restricted VRC01-class of antibodies targeting the HIV envelope CD4 binding site are a major focus of HIV vaccine strategies. However, a detailed analysis of VRC01-class antibody development has been limited by the rare nature of these responses during natural infection and the lack of longitudinal sampling of such responses. To inform vaccine strategies, we mapped the development of a VRC01-class antibody lineage (PCIN63) in the subtype C infected IAVI Protocol C neutralizer PC063. PCIN63 monoclonal antibodies had the hallmark VRC01-class features and demonstrated neutralization breadth similar to the prototype VRC01 antibody, but were 2- to 3-fold less mutated. Maturation occurred rapidly within â¼24 months of emergence of the lineage and somatic hypermutations accumulated at key contact residues. This longitudinal study of broadly neutralizing VRC01-class antibody lineage reveals early binding to the N276-glycan during affinity maturation, which may have implications for vaccine design.
Assuntos
Vacinas contra a AIDS/imunologia , Anticorpos Monoclonais/metabolismo , Anticorpos Neutralizantes/metabolismo , Anticorpos Amplamente Neutralizantes/metabolismo , Anticorpos Anti-HIV/metabolismo , Infecções por HIV/imunologia , HIV-1/fisiologia , Vacinas contra a AIDS/genética , Sequência de Aminoácidos , Anticorpos Monoclonais/genética , Anticorpos Neutralizantes/genética , Afinidade de Anticorpos , Linfócitos B/imunologia , Anticorpos Amplamente Neutralizantes/genética , Antígenos CD4/metabolismo , Regiões Determinantes de Complementaridade/genética , Anticorpos Anti-HIV/genética , Proteína gp120 do Envelope de HIV/imunologia , Proteína gp120 do Envelope de HIV/metabolismo , Humanos , Polissacarídeos/metabolismo , Ligação ProteicaRESUMO
Broadly neutralizing antibodies (bNAbs) against HIV-1 envelope (Env) inform vaccine design and are potential therapeutic agents. We identified SF12 and related bNAbs with up to 62% neutralization breadth from an HIV-infected donor. SF12 recognized a glycan-dominated epitope on Env's silent face and was potent against clade AE viruses, which are poorly covered by V3-glycan bNAbs. A 3.3Å cryo-EM structure of a SF12-Env trimer complex showed additional contacts to Env protein residues by SF12 compared with VRC-PG05, the only other known donor-derived silentface antibody, explaining SF12's increased neutralization breadth, potency, and resistance to Env mutation routes. Asymmetric binding of SF12 was associated with distinct N-glycan conformations across Env protomers, demonstrating intra-Env glycan heterogeneity. Administrating SF12 to HIV-1-infected humanized mice suppressed viremia and selected for viruses lacking the N448gp120 glycan. Effective bNAbs can therefore be raised against HIV-1 Env's silent face, suggesting their potential for HIV-1 prevention, therapy, and vaccine development.
Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Anti-HIV/imunologia , Infecções por HIV/imunologia , HIV-1/imunologia , Produtos do Gene env do Vírus da Imunodeficiência Humana/imunologia , Sequência de Aminoácidos , Anticorpos Neutralizantes/isolamento & purificação , Afinidade de Anticorpos/imunologia , Linfócitos B/imunologia , Linfócitos B/metabolismo , Epitopos/química , Epitopos/imunologia , Glicosilação , Anticorpos Anti-HIV/isolamento & purificação , Proteína gp120 do Envelope de HIV/química , Proteína gp120 do Envelope de HIV/imunologia , Infecções por HIV/virologia , HIV-1/classificação , HIV-1/genética , Humanos , Modelos Moleculares , Filogenia , Polissacarídeos/química , Polissacarídeos/metabolismo , Ligação Proteica/imunologia , Conformação Proteica , Produtos do Gene env do Vírus da Imunodeficiência Humana/química , Produtos do Gene env do Vírus da Imunodeficiência Humana/genética , Produtos do Gene env do Vírus da Imunodeficiência Humana/metabolismoRESUMO
An important class of HIV-1 broadly neutralizing antibodies, termed the VRC01 class, targets the conserved CD4-binding site (CD4bs) of the envelope glycoprotein (Env). An engineered Env outer domain (OD) eOD-GT8 60-mer nanoparticle has been developed as a priming immunogen for eliciting VRC01-class precursors and is planned for clinical trials. However, a substantial portion of eOD-GT8-elicited antibodies target non-CD4bs epitopes, potentially limiting its efficacy. We introduced N-linked glycans into non-CD4bs surfaces of eOD-GT8 to mask irrelevant epitopes and evaluated these mutants in a mouse model that expressed diverse immunoglobulin heavy chains containing human IGHV1-2∗02, the germline VRC01 VH segment. Compared to the parental eOD-GT8, a mutant with five added glycans stimulated significantly higher proportions of CD4bs-specific serum responses and CD4bs-specific immunoglobulin G+ B cells including VRC01-class precursors. These results demonstrate that glycan masking can limit elicitation of off-target antibodies and focus immune responses to the CD4bs, a major target of HIV-1 vaccine design.
Assuntos
Anticorpos Neutralizantes/imunologia , Sítios de Ligação de Anticorpos/imunologia , Antígenos CD4/imunologia , Anticorpos Anti-HIV/imunologia , HIV-1/imunologia , Vacinas contra a AIDS/imunologia , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Amplamente Neutralizantes , Linhagem Celular , Feminino , Técnicas de Introdução de Genes , Proteína gp120 do Envelope de HIV/imunologia , Infecções por HIV/imunologia , Infecções por HIV/prevenção & controle , Humanos , Cadeias Pesadas de Imunoglobulinas/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Polissacarídeos/químicaRESUMO
Virtually the entire surface of the HIV-1-envelope trimer is recognized by neutralizing antibodies, except for a highly glycosylated region at the center of the "silent face" on the gp120 subunit. From an HIV-1-infected donor, #74, we identified antibody VRC-PG05, which neutralized 27% of HIV-1 strains. The crystal structure of the antigen-binding fragment of VRC-PG05 in complex with gp120 revealed an epitope comprised primarily of N-linked glycans from N262, N295, and N448 at the silent face center. Somatic hypermutation occurred preferentially at antibody residues that interacted with these glycans, suggesting somatic development of glycan recognition. Resistance to VRC-PG05 in donor #74 involved shifting of glycan-N448 to N446 or mutation of glycan-proximal residue E293. HIV-1 neutralization can thus be achieved at the silent face center by glycan-recognizing antibody; along with other known epitopes, the VRC-PG05 epitope completes coverage by neutralizing antibody of all major exposed regions of the prefusion closed trimer.
Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Anti-HIV/imunologia , Proteína gp120 do Envelope de HIV/imunologia , Infecções por HIV/imunologia , HIV-1/imunologia , Polissacarídeos/imunologia , Sequência de Aminoácidos , Anticorpos Neutralizantes/química , Anticorpos Neutralizantes/genética , Anticorpos Neutralizantes/metabolismo , Antígenos Virais/química , Antígenos Virais/imunologia , Sítios de Ligação , Mapeamento de Epitopos , Epitopos/química , Epitopos/imunologia , Epitopos/metabolismo , Glicopeptídeos/química , Glicopeptídeos/imunologia , Glicosilação , Anticorpos Anti-HIV/química , Anticorpos Anti-HIV/genética , Anticorpos Anti-HIV/metabolismo , Proteína gp120 do Envelope de HIV/química , Proteína gp120 do Envelope de HIV/metabolismo , Humanos , Modelos Moleculares , Conformação Molecular , Polissacarídeos/química , Ligação Proteica/imunologia , Hipermutação Somática de Imunoglobulina/imunologia , Relação Estrutura-AtividadeRESUMO
Elicitation of VRC01-class broadly neutralizing antibodies (bnAbs) is an appealing approach for a preventative HIV-1 vaccine. Despite extensive investigations, strategies to induce VRC01-class bnAbs and overcome the barrier posed by the envelope N276 glycan have not been successful. Here, we inferred a high-probability unmutated common ancestor (UCA) of the VRC01 lineage and reconstructed the stages of lineage maturation. Env immunogens designed on reverted VRC01-class bnAbs bound to VRC01 UCA with affinity sufficient to activate naive B cells. Early mutations defined maturation pathways toward limited or broad neutralization, suggesting that focusing the immune response is likely required to steer B cell maturation toward the development of neutralization breadth. Finally, VRC01 lineage bnAbs with long CDR H3s overcame the HIV-1 N276 glycan barrier without shortening their CDR L1, revealing a solution for broad neutralization in which the heavy chain, not CDR L1, is the determinant to accommodate the N276 glycan.
Assuntos
Vacinas contra a AIDS/imunologia , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/imunologia , Infecções por HIV/imunologia , HIV-1/imunologia , Polissacarídeos/imunologia , Vacinas contra a AIDS/administração & dosagem , Vacinas contra a AIDS/genética , Sequência de Aminoácidos , Anticorpos Monoclonais/classificação , Anticorpos Monoclonais/genética , Anticorpos Neutralizantes/classificação , Anticorpos Neutralizantes/genética , Linfócitos B/imunologia , Linfócitos B/metabolismo , Sítios de Ligação/genética , Anticorpos Amplamente Neutralizantes , Antígenos CD4/genética , Antígenos CD4/imunologia , Antígenos CD4/metabolismo , Anticorpos Anti-HIV , Proteína gp120 do Envelope de HIV/genética , Proteína gp120 do Envelope de HIV/imunologia , Proteína gp120 do Envelope de HIV/metabolismo , Infecções por HIV/terapia , Infecções por HIV/virologia , HIV-1/efeitos dos fármacos , HIV-1/fisiologia , Humanos , Filogenia , Polissacarídeos/metabolismo , Homologia de Sequência de AminoácidosRESUMO
Advances in HIV-1 envelope glycoprotein (Env) design generate native-like trimers and high-resolution clade A, B, and G structures and elicit neutralizing antibodies. However, a high-resolution clade C structure is critical, as this subtype accounts for the majority of HIV infections worldwide, but well-ordered clade C Env trimers are more challenging to produce due to their instability. Based on targeted glycine substitutions in the Env fusion machinery, we defined a general approach that disfavors helical transitions leading to post-fusion conformations, thereby favoring the pre-fusion state. We generated a stabilized, soluble clade C Env (16055 NFL) and determined its crystal structure at 3.9 Å. Its overall conformation is similar to SOSIP.664 and native Env trimers but includes a covalent linker between gp120 and gp41, an engineered 201-433 disulfide bond, and density corresponding to 22 N-glycans. Env-structure-guided design strategies resulted in multiple homogeneous cross-clade immunogens with the potential to advance HIV vaccine development.
Assuntos
Substituição de Aminoácidos , Glicina/química , HIV-1/imunologia , Conformação Proteica em alfa-Hélice , Produtos do Gene env do Vírus da Imunodeficiência Humana/química , Produtos do Gene env do Vírus da Imunodeficiência Humana/imunologia , Anticorpos Neutralizantes/química , Anticorpos Neutralizantes/imunologia , Anticorpos Neutralizantes/metabolismo , Sítios de Ligação , Genótipo , Glicina/genética , Glicosilação , Anticorpos Anti-HIV/química , Anticorpos Anti-HIV/imunologia , Anticorpos Anti-HIV/metabolismo , Proteína gp120 do Envelope de HIV/química , Proteína gp120 do Envelope de HIV/genética , Proteína gp120 do Envelope de HIV/imunologia , Proteína gp41 do Envelope de HIV/química , Proteína gp41 do Envelope de HIV/genética , Proteína gp41 do Envelope de HIV/imunologia , HIV-1/classificação , HIV-1/genética , Humanos , Modelos Moleculares , Mutação , Ligação Proteica/imunologia , Engenharia de Proteínas , Multimerização Proteica , Estabilidade Proteica , Proteólise , Solubilidade , Relação Estrutura-Atividade , Produtos do Gene env do Vírus da Imunodeficiência Humana/genéticaRESUMO
Apex broadly neutralizing HIV antibodies (bnAbs) recognize glycans and protein surface close to the 3-fold axis of the envelope (Env) trimer and are among the most potent and broad Abs described. The evolution of apex bnAbs from one donor (CAP256) has been studied in detail and many Abs at different stages of maturation have been described. Using diverse engineering tools, we investigated the involvement of glycan recognition in the development of the CAP256.VRC26 Ab lineage. We found that sialic acid-bearing glycans were recognized by germline-encoded and somatically mutated residues on the Ab heavy chain. This recognition provided an "anchor" for the Abs as the core protein epitope varies, prevented complete neutralization escape, and eventually led to broadening of the response. These findings illustrate how glycan-specific maturation enables a human Ab to cope with pathogen escape mechanisms and will aid in optimization of immunization strategies to induce V2 apex bnAb responses.
Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Anti-HIV/imunologia , Infecções por HIV/imunologia , Infecções por HIV/metabolismo , HIV-1/imunologia , Polissacarídeos/metabolismo , Sequência de Aminoácidos , Afinidade de Anticorpos/imunologia , Formação de Anticorpos/imunologia , Sítios de Ligação , Epitopos/imunologia , Anticorpos Anti-HIV/química , Anticorpos Anti-HIV/classificação , Anticorpos Anti-HIV/genética , Proteína gp120 do Envelope de HIV/química , Proteína gp120 do Envelope de HIV/imunologia , Infecções por HIV/virologia , Humanos , Cadeias Pesadas de Imunoglobulinas/genética , Modelos Moleculares , Ácido N-Acetilneuramínico/metabolismo , Testes de Neutralização , Fragmentos de Peptídeos/imunologia , Filogenia , Ligação Proteica/imunologia , Conformação Proteica , Multimerização ProteicaRESUMO
Most HIV-1-specific neutralizing antibodies isolated to date exhibit unusual characteristics that complicate their elicitation. Neutralizing antibodies that target the V1V2 apex of the HIV-1 envelope (Env) trimer feature unusually long protruding loops, which enable them to penetrate the HIV-1 glycan shield. As antibodies with loops of requisite length are created through uncommon recombination events, an alternative mode of apex binding has been sought. Here, we isolated a lineage of Env apex-directed neutralizing antibodies, N90-VRC38.01-11, by using virus-like particles and conformationally stabilized Env trimers as B cell probes. A crystal structure of N90-VRC38.01 with a scaffolded V1V2 revealed a binding mode involving side-chain-to-side-chain interactions that reduced the distance the antibody loop must traverse the glycan shield, thereby facilitating V1V2 binding via a non-protruding loop. The N90-VRC38 lineage thus identifies a solution for V1V2-apex binding that provides a more conventional B cell pathway for vaccine design.
Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Anti-HIV/imunologia , Proteína gp120 do Envelope de HIV/imunologia , Infecções por HIV/imunologia , HIV-1/imunologia , Fragmentos de Peptídeos/imunologia , Conformação Proteica , Produtos do Gene env do Vírus da Imunodeficiência Humana/imunologia , Sequência de Aminoácidos , Anticorpos Neutralizantes/química , Anticorpos Neutralizantes/metabolismo , Linfócitos B/imunologia , Linfócitos B/metabolismo , Sítios de Ligação , Regiões Determinantes de Complementaridade/química , Regiões Determinantes de Complementaridade/imunologia , Anticorpos Anti-HIV/química , Anticorpos Anti-HIV/metabolismo , Proteína gp120 do Envelope de HIV/química , Proteína gp120 do Envelope de HIV/metabolismo , Infecções por HIV/virologia , Humanos , Modelos Moleculares , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Filogenia , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Multimerização Proteica , Vacinas de Partículas Semelhantes a Vírus/química , Vacinas de Partículas Semelhantes a Vírus/imunologia , Vacinas de Partículas Semelhantes a Vírus/metabolismoRESUMO
The humoral immune response after acute infection with HIV-1 is delayed and ineffective. The HIV-1 envelope protein gp120 binds to and signals through integrin α4ß7 on T cells. We found that gp120 also bound to and signaled through α4ß7 on naive B cells, which resulted in an abortive proliferative response. In primary B cells, signaling by gp120 through α4ß7 resulted in increased expression of the immunosuppressive cytokine TGF-ß1 and FcRL4, an inhibitory receptor expressed on B cells. Coculture of B cells with HIV-1-infected autologous CD4(+) T cells also increased the expression of FcRL4 by B cells. Our findings indicated that in addition to mediating chronic activation of the immune system, viral proteins contributed directly to HIV-1-associated B cell dysfunction. Our studies identify a mechanism whereby the virus may subvert the early HIV-1-specific humoral immune response.
Assuntos
Linfócitos B/imunologia , Proliferação de Células , Proteína gp120 do Envelope de HIV/imunologia , Receptores Fc/imunologia , Fator de Crescimento Transformador beta1/imunologia , Animais , Linfócitos B/citologia , Linfócitos B/metabolismo , Linfócitos T CD4-Positivos/citologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/virologia , Células CHO , Células Cultivadas , Técnicas de Cocultura , Cricetinae , Cricetulus , Citometria de Fluxo , Proteína gp120 do Envelope de HIV/genética , Proteína gp120 do Envelope de HIV/metabolismo , HIV-1/genética , HIV-1/imunologia , HIV-1/fisiologia , Interações Hospedeiro-Patógeno/imunologia , Humanos , Integrinas/genética , Integrinas/imunologia , Integrinas/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , Ligação Proteica/imunologia , Receptores Fc/genética , Receptores Fc/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/imunologia , Transcriptoma/genética , Transcriptoma/imunologia , Fator de Crescimento Transformador beta1/genética , Fator de Crescimento Transformador beta1/metabolismoRESUMO
Detailed studies of the broadly neutralizing antibodies (bNAbs) that underlie the best available examples of the humoral immune response to HIV are providing important information for the development of therapies and prophylaxis for HIV-1 infection. Here, we report a CD4-binding site (CD4bs) antibody, named N6, that potently neutralized 98% of HIV-1 isolates, including 16 of 20 that were resistant to other members of its class. N6 evolved a mode of recognition such that its binding was not impacted by the loss of individual contacts across the immunoglobulin heavy chain. In addition, structural analysis revealed that the orientation of N6 permitted it to avoid steric clashes with glycans, which is a common mechanism of resistance. Thus, an HIV-1-specific bNAb can achieve potent, near-pan neutralization of HIV-1, making it an attractive candidate for use in therapy and prophylaxis.
Assuntos
Anticorpos Neutralizantes/imunologia , Sítios de Ligação de Anticorpos/imunologia , Anticorpos Anti-HIV/imunologia , Infecções por HIV/imunologia , HIV-1/imunologia , Especificidade de Anticorpos , Linfócitos T CD4-Positivos/imunologia , Separação Celular , Proteína gp120 do Envelope de HIV/imunologia , HumanosRESUMO
VRC01-class antibodies neutralize diverse HIV-1 strains by targeting the conserved CD4-binding site. Despite extensive investigations, crucial events in the early stage of VRC01 development remain elusive. We demonstrated how VRC01-class antibodies emerged in a Chinese donor by antigen-specific single B cell sorting, structural and functional studies, and longitudinal antibody and virus repertoire analyses. A monoclonal antibody DRVIA7 with modest neutralizing breadth was isolated that displayed a subset of VRC01 signatures. X-ray and EM structures revealed a VRC01-like angle of approach, but less favorable interactions between the DRVIA7 light-chain CDR1 and the N terminus with N276 and V5 glycans of gp120. Although the DRVIA7 lineage was unable to acquire broad neutralization, longitudinal analysis revealed a repertoire-encoded VRC01 light-chain CDR3 signature and VRC01-like neutralizing heavy-chain precursors that rapidly matured within 2 years. Thus, light chain accommodation of the glycan shield should be taken into account in vaccine design targeting this conserved site of vulnerability.
Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/imunologia , Sítios de Ligação de Anticorpos/imunologia , Anticorpos Anti-HIV/imunologia , Proteína gp120 do Envelope de HIV/imunologia , Produtos do Gene env do Vírus da Imunodeficiência Humana/imunologia , Sequência de Aminoácidos , Anticorpos Amplamente Neutralizantes , Linfócitos T CD4-Positivos/imunologia , Infecções por HIV/imunologia , HIV-1/imunologia , Humanos , Dados de Sequência MolecularRESUMO
The dense patch of high-mannose-type glycans surrounding the N332 glycan on the HIV envelope glycoprotein (Env) is targeted by multiple broadly neutralizing antibodies (bnAbs). This region is relatively conserved, implying functional importance, the origins of which are not well understood. Here we describe the isolation of new bnAbs targeting this region. Examination of these and previously described antibodies to Env revealed that four different bnAb families targeted the (324)GDIR(327) peptide stretch at the base of the gp120 V3 loop and its nearby glycans. We found that this peptide stretch constitutes part of the CCR5 co-receptor binding site, with the high-mannose patch glycans serving to camouflage it from most antibodies. GDIR-glycan bnAbs, in contrast, bound both (324)GDIR(327) peptide residues and high-mannose patch glycans, which enabled broad reactivity against diverse HIV isolates. Thus, as for the CD4 binding site, bnAb effectiveness relies on circumventing the defenses of a critical functional region on Env.