Paring Down HIV Env: Design and Crystal Structure of a Stabilized Inner Domain of HIV-1 gp120 Displaying a Major ADCC Target of the A32 Region

Tolbert, W.D.; Gohain, Neelakshi; Veillette, Maxime; Chapleau, Jean-Philippe; Orlandi, Chiara; Visciano, Maria Luisa; Ebadi, Maryam; DeVico, Anthony L.; Fouts, Timothy; Finzi, Andrés; Lewis, George K.; Pazgier, Marzena

doi:10.1016/j.str.2016.03.005

Cited by 54 publications

(115 citation statements)

References 60 publications

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“…infected individuals and to mediate potent ADCC responses (13,14,18,(20)(21)(22)(23)(24)(25)(26). Therefore, our results raise the intriguing possibility that histidine 375 present in the predominant strain replicating in Thailand might have contributed to the efficacy of the trial by spontaneously exposing epitopes recognized by ADCC-mediating antibodies elicited by the RV144 vaccine regimen.…”

Section: Figmentioning

confidence: 76%

“…Accordingly, we recently reported that the transition of Env to the CD4-bound conformation is required for efficient interactions with ADCC-mediating antibodies (14). We reported that the replacement of serine 375 by a tryptophan residue (S375W) enhanced the exposure of epitopes recognized by anti-cluster A antibodies, known to mediate potent ADCC responses (13,14,18,(20)(21)(22)(23)(24)(25)(26). Thus, the transition of Env from the unbound to the CD4-bound conformation appears to be a prerequisite for the exposure of inner-domain ADCC epitopes.…”

mentioning

confidence: 99%

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Influence of the Envelope gp120 Phe 43 Cavity on HIV-1 Sensitivity to Antibody-Dependent Cell-Mediated Cytotoxicity Responses

Prévost

Zoubchenok

Richard

et al. 2017

J Virol

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HIV-1-infected cells presenting envelope glycoproteins (Env) in the CD4-bound conformation on their surface are preferentially targeted by antibodydependent cellular-mediated cytotoxicity (ADCC). HIV-1 has evolved sophisticated mechanisms to avoid the exposure of Env ADCC epitopes by downregulating CD4 and by limiting the overall amount of Env on the cell surface. In HIV-1, substitution of large residues such as histidine or tryptophan for serine 375 (S375H/W) in the gp120 Phe 43 cavity, where Phe 43 of CD4 contacts gp120, results in the spontaneous sampling of an Env conformation closer to the CD4-bound state. While residue S375 is well conserved in the majority of group M HIV-1 isolates, CRF01_ AE strains have a naturally occurring histidine at this position (H375). Interestingly, CRF01_AE is the predominant circulating strain in Thailand, where the RV144 trial took place. In this trial, which resulted in a modest degree of protection, ADCC responses were identified as being part of the correlate of protection. Here we investigate the influence of the Phe 43 cavity on ADCC responses. Filling this cavity with a histidine or tryptophan residue in Env with a natural serine residue at this position (S375H/W) increased the susceptibility of HIV-1-infected cells to ADCC. Conversely, the replacement of His 375 by a serine residue (H375S) within HIV-1 CRF01_AE decreased the efficiency of the ADCC response. Our results raise the intriguing possibility that the presence of His 375 in the circulating strain where the RV144 trial was held contributed to the observed vaccine efficacy.

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Section: Figmentioning

confidence: 76%

mentioning

confidence: 99%

Influence of the Envelope gp120 Phe 43 Cavity on HIV-1 Sensitivity to Antibody-Dependent Cell-Mediated Cytotoxicity Responses

Prévost

Zoubchenok

Richard

et al. 2017

J Virol

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“…Since it has been previously reported that the inner domain layers modulate recognition of gp120 by CD4i antibodies (15,16,30), we next examined the binding capacity of our panel of W69 gp120 variants to CD4i antibodies recognizing the coreceptor binding site (CoRBS; 17b and 48d) and anti-cluster A antibodies, known to be potent mediators of ADCC responses (A32, N5-i5, and N60-i3) (15,19,43,45,46). It was previously shown that CD4i antibodies preferentially recognize the CD4-triggered monomeric gp120, but they are still capable of binding to unliganded gp120 with roughly 10-to 20-fold lower affinities (15,18). Figure 3 and Table 2 show the binding of CoRBS and anti-cluster A antibodies to W69 mutant variants as quantified by immunoprecipitation and SPR, respectively.…”

Section: Resultsmentioning

confidence: 96%

“…Moreover, among these residues, W69 was recently shown to be important for efficient Env recognition by antibody-dependent cellular cytotoxicity (ADCC)-mediating anti-cluster A antibodies and also by sera from HIV-1-infected individuals (17)(18)(19)(20). Since W69 is located at the interface between layer 1 and layer 2 of the inner domain, we evaluated the contribution of hydrophobicity at this position to Env conformational changes.…”

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confidence: 99%

A Highly Conserved gp120 Inner Domain Residue Modulates Env Conformation and Trimer Stability

Ding

Tolbert

Prévost

et al. 2016

J Virol

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Previous studies have shown that highly conserved residues in the inner domain of gp120 are required for HIV-1 envelope glycoprotein ( We evaluated the contribution of the hydrophobicity of W69 to conformational changes of Env by replacing it with a series of residues with aliphatic or aromatic side chains of decreasing chain length. We have found that the hydrophobicity of residue 69 is important for Env processing, CD4 binding, and its transition to the CD4-bound conformation. The most deleterious effect was observed when W69 was replaced with alanine or glycine residues. However, the functions lost due to W69 mutations could be progressively restored with amino acids of increasing aliphatic chain length and fully recovered with residues bearing an aromatic ring. Interestingly, poor CD4 binding of W69A could be fully restored by introducing a compensatory mutation within layer 2 (S115W). Structural studies of HIV-1 gp120 core e W69A/S115W mutant bound to the CD4 peptide mimetic M48U1 and Fab of anti-cluster A antibody N60-i3 revealed no perturbations to the overall structure of the double mutant compared to the wild-type protein but identified higher mobility within the interface between layer 1 and layer 2, the bridging sheet region, and the CD4 binding site. HIV-1 envelope glycoproteins (Env) play a key role during the first step of viral infection. Mature HIV-1 Env trimers are the products of a proteolytic cleavage of gp160 precursor polypeptides into gp120 (SU) and gp41 (TM) subunits. Mature metastable Env is a consolidation of three gp120 with three gp41 transmembrane subunits related in a labile noncovalent manner (1). Binding of gp120 exterior subunit to its cellular receptor, CD4, initiates viral entry (2, 3). CD4 binding allows gp120 conformational rearrangement, which is required for its attachment to CCR5 or CXCR4 chemokine coreceptors (4-11), upon which further conformational changes expose the gp41 helical heptad repeat segment (HR1), resulting in the formation of the prehairpin intermediates followed by a transition to a six-helix bundle composed of HR1 and HR2. These conformational changes lead to viral and cellular membrane fusion (12)(13)(14). CD4-induced changes allow the trimer to switch from a metastable high-energy unliganded form to a low-energy stable state.Recent studies have shown that highly conserved residues in the inner domain of gp120 are required for HIV-1 Env transitions to the CD4-bound conformation and efficient CD4 binding (15,16). Moreover, among these residues, W69 was recently shown to be important for efficient Env recognition by antibody-dependent cellular cytotoxicity (ADCC)-mediating anti-cluster A antibodies and also by sera from HIV-1-infected individuals (17-20). Since W69 is located at the interface between layer 1 and layer 2 of the

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“…The conformation of the CD4i epitope has been captured in a truncated and stabilised gp120 innerdomain mini-protein which binds A32 and other CD4i specific mAbs [136]. This has been suggested to be a potential vaccine candidate for eliciting CD4i focused antibody responses but will first require an evaluation of the importance of off target killing of uninfected bystander cells to determine if this approach will be effective.…”

Section: Hiv Evasion and Subversion Of Fcγr-mediated Ab Functionsmentioning

confidence: 99%

Antibody functional assays as measures of Fc receptor-mediated immunity to HIV - new technologies and their impact on the HIV vaccine field.

Wines¹,

Billings²,

Mcleand³

et al. 2017

CHR

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Background:There is now intense interest in the role of HIV-specific antibodies and the engagement of FcγR functions in the control and prevention of HIV infection. The analyses of the RV144 vaccine trial, natural progression cohorts, and macaque models all point to a role for Fc-dependent effector functions, such as cytotoxicity (ADCC) or phagocytosis (ADCP), in the control of HIV. However, reliable assays that can be reproducibly used across different laboratories to measure Fcdependent functions, such as antibody dependent cellular cytotoxicity (ADCC) are limited. Method: This brief review highlights the importance of Fc properties for immunity to HIV, particularly via FcγR diversity and function. We discuss assays used to study FcR mediated functions of HIV-specific Ab, including our recently developed novel cell-free ELISA using homo-dimeric FcγR ectodomains to detect functionally relevant viral antigen-specific antibodies. Results: The binding of these dimeric FcγR ectodomains, to closely spaced pairs of IgG Fc, mimics the engagement and cross-linking of Fc receptors by IgG opsonized virions or infected cells as the essential prerequisite to the induction of Ab-dependent effector functions. The dimeric FcγR ELISA reliably correlates with ADCC in patient responses to influenza. The assay is amenable to high throughput and could be standardized across laboratories. Conclusion: We propose the assay has broader implications for the evaluation of the quality of antibody responses in viral infections and for the rapid evaluation of responses in vaccine development campaigns for HIV and other viral infections.

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Paring Down HIV Env: Design and Crystal Structure of a Stabilized Inner Domain of HIV-1 gp120 Displaying a Major ADCC Target of the A32 Region

Cited by 54 publications

References 60 publications

Influence of the Envelope gp120 Phe 43 Cavity on HIV-1 Sensitivity to Antibody-Dependent Cell-Mediated Cytotoxicity Responses

Influence of the Envelope gp120 Phe 43 Cavity on HIV-1 Sensitivity to Antibody-Dependent Cell-Mediated Cytotoxicity Responses

A Highly Conserved gp120 Inner Domain Residue Modulates Env Conformation and Trimer Stability

Antibody functional assays as measures of Fc receptor-mediated immunity to HIV - new technologies and their impact on the HIV vaccine field.

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