Polyclonal Broadly Neutralizing Antibody Activity Characterized by CD4 Binding Site and V3-Glycan Antibodies in a Subset of HIV-1 Virus Controllers

Broadly neutralizing antibodies (bNAbs), known to mediate immune control of HIV-1 infection, only develop in a small subset of HIV-1 infected individuals. Despite being traditionally associated with patients with high viral loads, bNAbs have also been observed in therapy naïve HIV-1+ patients naturally controlling virus replication [Virus Controllers (VCs)]. Thus, dissecting the bNAb response in VCs will provide key information about what constitutes an effective humoral response to natural HIV-1 infection. In this study, we identified a polyclonal bNAb response to natural HIV-1 infection targeting CD4 binding site (CD4bs), V3-glycan, gp120-gp41 interface and membrane-proximal external region (MPER) epitopes on the HIV-1 envelope (Env). The polyclonal antiviral antibody (Ab) response also included antibody-dependent cellular phagocytosis of clade AE, B and C viruses, consistent with both the Fv and Fc domain contributing to function. Sequence analysis of envs from one of the VCs revealed features consistent with potential immune pressure and virus escape from V3-glycan targeting bNAbs. Epitope mapping of the polyclonal bNAb response in VCs with bNAb activity highlighted the presence of gp120-gp41 interface and CD4bs antibody classes with similar binding profiles to known potent bNAbs. Thus, these findings reveal the induction of a broad and polyfunctional humoral response in VCs in response to natural HIV-1 infection.

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Characterization and Implementation of a Diverse Simian Immunodeficiency Virus SIVsm Envelope Panel in the Assessment of Neutralizing Antibody Breadth Elicited in Rhesus Macaques by Multimodal Vaccines Expressing the SIVmac239 Envelope

Journal of Virology ◽

10.1128/jvi.01221-14 ◽

2015 ◽

Vol 89 (16) ◽

pp. 8130-8151 ◽

Cited By ~ 18

Author(s):

Katie M. Kilgore ◽

Megan K. Murphy ◽

Samantha L. Burton ◽

Katherine S. Wetzel ◽

S. Abigail Smith ◽

...

Keyword(s):

Simian Immunodeficiency Virus ◽

Nonhuman Primate ◽

Neutralizing Antibodies ◽

Rhesus Macaques ◽

Neutralizing Antibody ◽

Cd40 Ligand ◽

Antibody Activity ◽

Immunodeficiency Virus ◽

Antibody Profile ◽

Hiv 1

ABSTRACTAntibodies that can neutralize diverse viral strains are likely to be an important component of a protective human immunodeficiency virus type 1 (HIV-1) vaccine. To this end, preclinical simian immunodeficiency virus (SIV)-based nonhuman primate immunization regimens have been designed to evaluate and enhance antibody-mediated protection. However, these trials often rely on a limited selection of SIV strains with extreme neutralization phenotypes to assess vaccine-elicited antibody activity. To mirror the viral panels used to assess HIV-1 antibody breadth, we created and characterized a novel panel of 14 genetically and phenotypically diverse SIVsm envelope (Env) glycoproteins. To assess the utility of this panel, we characterized the neutralizing activity elicited by four SIVmac239 envelope-expressing DNA/modified vaccinia virus Ankara vector- and protein-based vaccination regimens that included the immunomodulatory adjuvants granulocyte-macrophage colony-stimulating factor, Toll-like receptor (TLR) ligands, and CD40 ligand. The SIVsm Env panel exhibited a spectrum of neutralization sensitivity to SIV-infected plasma pools and monoclonal antibodies, allowing categorization into three tiers. Pooled sera from 91 rhesus macaques immunized in the four trials consistently neutralized only the highly sensitive tier 1a SIVsm Envs, regardless of the immunization regimen. The inability of vaccine-mediated antibodies to neutralize the moderately resistant tier 1b and tier 2 SIVsm Envs defined here suggests that those antibodies were directed toward epitopes that are not accessible on most SIVsm Envs. To achieve a broader and more effective neutralization profile in preclinical vaccine studies that is relevant to known features of HIV-1 neutralization, more emphasis should be placed on optimizing the Env immunogen, as the neutralization profile achieved by the addition of adjuvants does not appear to supersede the neutralizing antibody profile determined by the immunogen.IMPORTANCEMany in the HIV/AIDS vaccine field believe that the ability to elicit broadly neutralizing antibodies capable of blocking genetically diverse HIV-1 variants is a critical component of a protective vaccine. Various SIV-based nonhuman primate vaccine studies have investigated ways to improve antibody-mediated protection against a heterologous SIV challenge, including administering adjuvants that might stimulate a greater neutralization breadth. Using a novel SIV neutralization panel and samples from four rhesus macaque vaccine trials designed for cross comparison, we show that different regimens expressing the same SIV envelope immunogen consistently elicit antibodies that neutralize only the very sensitive tier 1a SIV variants. The results argue that the neutralizing antibody profile elicited by a vaccine is primarily determined by the envelope immunogen and is not substantially broadened by including adjuvants, resulting in the conclusion that the envelope immunogen itself should be the primary consideration in efforts to elicit antibodies with greater neutralization breadth.

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Neutralization Properties of Simian Immunodeficiency Viruses Infecting Chimpanzees and Gorillas

mBio ◽

10.1128/mbio.00296-15 ◽

2015 ◽

Vol 6 (2) ◽

Cited By ~ 17

Author(s):

Hannah J. Barbian ◽

Julie M. Decker ◽

Frederic Bibollet-Ruche ◽

Rachel P. Galimidi ◽

Anthony P. West ◽

...

Keyword(s):

T Cells ◽

Binding Site ◽

Pan Troglodytes ◽

Neutralizing Antibodies ◽

Gorilla Gorilla ◽

Protective Capacity ◽

Content Type ◽

Ccr5 Receptor ◽

Cd4 Binding Site ◽

Hiv 1

ABSTRACTBroadly cross-reactive neutralizing antibodies (bNabs) represent powerful tools to combat human immunodeficiency virus type 1 (HIV-1) infection. Here, we examined whether HIV-1-specific bNabs are capable of cross-neutralizing distantly related simian immunodeficiency viruses (SIVs) infecting central (Pan troglodytestroglodytes) (SIVcpzPtt) and eastern (Pan troglodytesschweinfurthii) (SIVcpzPts) chimpanzees (n= 11) as well as western gorillas (Gorilla gorilla gorilla) (SIVgor) (n= 1). We found that bNabs directed against the CD4 binding site (n= 10), peptidoglycans at the base of variable loop 3 (V3) (n= 5), and epitopes at the interface of surface (gp120) and membrane-bound (gp41) envelope glycoproteins (n= 5) failed to neutralize SIVcpz and SIVgor strains. In addition, apex V2-directed bNabs (n= 3) as well as llama-derived (heavy chain only) antibodies (n= 6) recognizing both the CD4 binding site and gp41 epitopes were either completely inactive or neutralized only a fraction of SIVcpzPttstrains. In contrast, one antibody targeting the membrane-proximal external region (MPER) of gp41 (10E8), functional CD4 and CCR5 receptor mimetics (eCD4-Ig, eCD4-Igmim2, CD4-218.3-E51, and CD4-218.3-E51-mim2), as well as mono- and bispecific anti-human CD4 (iMab and LM52) and CCR5 (PRO140, PRO140-10E8) receptor antibodies neutralized >90% of SIVcpz and SIVgor strains with low-nanomolar (0.13 to 8.4 nM) potency. Importantly, the latter antibodies blocked virus entry not only in TZM-bl cells but also in Cf2Th cells expressing chimpanzee CD4 and CCR5 and neutralized SIVcpz in chimpanzee CD4+T cells, with 50% inhibitory concentrations (IC50s) ranging from 3.6 to 40.5 nM. These findings provide new insight into the protective capacity of anti-HIV-1 bNabs and identify candidates for further development to combat SIVcpz infection.IMPORTANCESIVcpz is widespread in wild-living chimpanzees and can cause AIDS-like immunopathology and clinical disease. HIV-1 infection of humans can be controlled by antiretroviral therapy; however, treatment of wild-living African apes with current drug regimens is not feasible. Nonetheless, it may be possible to curb the spread of SIVcpz in select ape communities using vectored immunoprophylaxis and/or therapy. Here, we show that antibodies and antibody-like inhibitors developed to combat HIV-1 infection in humans are capable of neutralizing genetically diverse SIVcpz and SIVgor strains with considerable breadth and potency, including in primary chimpanzee CD4+T cells. These reagents provide an important first step toward translating intervention strategies currently developed to treat and prevent AIDS in humans to SIV-infected apes.

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Broad neutralization by a combination of antibodies recognizing the CD4 binding site and a new conformational epitope on the HIV-1 envelope protein

Journal of Experimental Medicine ◽

10.1084/jem.20120423 ◽

2012 ◽

Vol 209 (8) ◽

pp. 1469-1479 ◽

Cited By ~ 123

Author(s):

Florian Klein ◽

Christian Gaebler ◽

Hugo Mouquet ◽

D. Noah Sather ◽

Clara Lehmann ◽

...

Keyword(s):

Binding Site ◽

Envelope Protein ◽

Neutralizing Antibodies ◽

Conformational Epitope ◽

Broadly Neutralizing Antibodies ◽

Cd4 Binding Site ◽

Capture Method ◽

Anti Hiv ◽

Hiv 1 ◽

Viral Isolates

Two to three years after infection, a fraction of HIV-1–infected individuals develop serologic activity that neutralizes most viral isolates. Broadly neutralizing antibodies that recognize the HIV-1 envelope protein have been isolated from these patients by single-cell sorting and by neutralization screens. Here, we report a new method for anti–HIV-1 antibody isolation based on capturing single B cells that recognize the HIV-1 envelope protein expressed on the surface of transfected cells. Although far less efficient than soluble protein baits, the cell-based capture method identified antibodies that bind to a new broadly neutralizing epitope in the vicinity of the V3 loop and the CD4-induced site (CD4i). The new epitope is expressed on the cell surface form of the HIV-1 spike, but not on soluble forms of the same envelope protein. Moreover, the new antibodies complement the neutralization spectrum of potent broadly neutralizing anti-CD4 binding site (CD4bs) antibodies obtained from the same individual. Thus, combinations of potent broadly neutralizing antibodies with complementary activity can account for the breadth and potency of naturally arising anti–HIV-1 serologic activity. Therefore, vaccines aimed at eliciting anti–HIV-1 serologic breadth and potency should not be limited to single epitopes.

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Selection Pressure on HIV-1 Envelope by Broadly Neutralizing Antibodies to the Conserved CD4-Binding Site

Journal of Virology ◽

10.1128/jvi.07139-11 ◽

2012 ◽

Vol 86 (10) ◽

pp. 5844-5856 ◽

Cited By ~ 60

Author(s):

X. Wu ◽

C. Wang ◽

S. O'Dell ◽

Y. Li ◽

B. F. Keele ◽

...

Keyword(s):

Binding Site ◽

Neutralizing Antibodies ◽

Selection Pressure ◽

Broadly Neutralizing Antibodies ◽

Cd4 Binding Site ◽

Hiv 1

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Elicitation of HIV-1-neutralizing antibodies against the CD4-binding site

Current Opinion in HIV and AIDS ◽

10.1097/coh.0b013e328363a90e ◽

2013 ◽

Vol 8 (5) ◽

pp. 382-392 ◽

Cited By ~ 24

Author(s):

Ivelin S. Georgiev ◽

M. Gordon Joyce ◽

Tongqing Zhou ◽

Peter D. Kwong

Keyword(s):

Binding Site ◽

Neutralizing Antibodies ◽

Cd4 Binding Site ◽

Hiv 1

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Comparative Immunogenicity of Subtype A Human Immunodeficiency Virus Type 1 Envelope Exhibiting Differential Exposure of Conserved Neutralization Epitopes

Journal of Virology ◽

10.1128/jvi.01687-09 ◽

2009 ◽

Vol 84 (5) ◽

pp. 2573-2584 ◽

Cited By ~ 18

Author(s):

Catherine A. Blish ◽

D. Noah Sather ◽

George Sellhorn ◽

Leonidas Stamatatos ◽

Yide Sun ◽

...

Keyword(s):

Antibody Response ◽

Neutralizing Antibodies ◽

Vaccine Development ◽

Neutralizing Antibody ◽

Immunodeficiency Virus ◽

Cd4 Binding Site ◽

Variable Loops ◽

Linear Epitopes ◽

Subtype A ◽

Hiv 1

ABSTRACT Development of broadly cross-reactive neutralizing antibodies (NAbs) remains a major goal of HIV-1 vaccine development, but most candidate envelope immunogens have had limited ability to cross-neutralize heterologous strains. To evaluate the immunogenicity of subtype A variants of HIV-1, rabbits were immunized with pairs of closely related subtype A envelopes from the same individual. In each immunogen pair, one variant was readily neutralized by a variety of monoclonal antibodies and plasma antibodies, while the other was neutralization resistant, suggesting differences in the exposures of key epitopes. The breadth of the antibody response was evaluated against subtype A, B, C, and D variants of HIV-1. The specificity of the immunogen-derived neutralizing antibody response was also compared to that of the infected individuals from whom these variants were cloned. None of the immunogens produced broad neutralizing antibodies in immunized animals, and most of the neutralizing antibodies were directed to the variable loops, particularly the V3 loop. No detectable antibodies to either of the potentially exposed conserved epitopes, the membrane proximal external region, or the CD4 binding site were found with immunized rabbits. In contrast, relatively little of the neutralizing activity within the plasma samples of the infected individuals was directed to linear epitopes within the variable loops. These data indicate that immunogens designed to expose conserved regions did not enhance generation of broadly neutralizing antibodies in comparison with the immunogens that failed to expose those regions using this immunization approach.

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V3-specific neutralizing antibodies in sera from HIV-1 gp160-immunized volunteers block virus fusion and act synergistically with human monoclonal antibody to the conformation-dependent CD4 binding site of gp120. NIH-NIAID AIDS Vaccine Clinical Trials Network.

Journal of Clinical Investigation ◽

10.1172/jci116658 ◽

1993 ◽

Vol 92 (2) ◽

pp. 840-847 ◽

Cited By ~ 43

Author(s):

D C Montefiori ◽

B S Graham ◽

J Zhou ◽

R A Bucco ◽

...

Keyword(s):

Monoclonal Antibody ◽

Clinical Trials ◽

Binding Site ◽

Neutralizing Antibodies ◽

Human Monoclonal Antibody ◽

Aids Vaccine ◽

Virus Fusion ◽

Cd4 Binding Site ◽

Hiv 1

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Neutralizing antibodies induced in immunized macaques recognize the CD4-binding site on an occluded-open HIV-1 envelope trimer

10.1101/2021.11.02.466200 ◽

2021 ◽

Author(s):

Zhi Yang ◽

Kim-Marie A. Dam ◽

Michael D. Bridges ◽

Magnus A.G. Hoffmann ◽

Andrew T. DeLaitsch ◽

...

Keyword(s):

Binding Site ◽

Neutralizing Antibodies ◽

Resonance Spectroscopy ◽

Broadly Neutralizing Antibodies ◽

Receptor Binding Site ◽

Double Electron ◽

Immunogen Design ◽

Cd4 Binding Site ◽

Double Electron Electron Resonance ◽

Hiv 1

Broadly-neutralizing antibodies (bNAbs) against HIV-1 Env can protect from infection. We characterized Ab1303 and Ab1573, neutralizing CD4-binding site (CD4bs) antibodies, isolated from sequentially-immunized macaques. Ab1303/Ab1573 binding was observed only when Env trimers were not constrained in the closed, prefusion conformation. Fab-Env cryo-EM structures showed that both antibodies recognized the CD4bs on Env trimer with an occluded-open conformation between closed, as targeted by bNAbs, and fully-open, as recognized by CD4. The occluded-open Env trimer conformation included outwardly-rotated gp120 subunits, but unlike CD4-bound Envs, did not exhibit V1V2 displacement, co-receptor binding site exposure, or a 4-stranded gp120 bridging sheet. Inter-protomer distances within trimers measured by double electron-electron resonance spectroscopy suggested an equilibrium between occluded-open and closed Env conformations, consistent with Ab1303/Ab1573 binding stabilizing an existing conformation. Studies of Ab1303/Ab1573 demonstrate that CD4bs neutralizing antibodies that bind open Env trimers can be raised by immunization, thereby informing immunogen design and antibody therapeutic efforts.

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ADCC-mediating non-neutralizing antibodies can exert immune pressure in early HIV-1 infection

PLoS Pathogens ◽

10.1371/journal.ppat.1010046 ◽

2021 ◽

Vol 17 (11) ◽

pp. e1010046

Author(s):

Dieter Mielke ◽

Gama Bandawe ◽

Jie Zheng ◽

Jennifer Jones ◽

Melissa-Rose Abrahams ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Immune Escape ◽

Viral Evolution ◽

Neutralizing Antibody ◽

Protective Role ◽

Viral Escape ◽

Immune Pressure ◽

Control Virus ◽

Kinetics Of ◽

Hiv 1

Despite antibody-dependent cellular cytotoxicity (ADCC) responses being implicated in protection from HIV-1 infection, there is limited evidence that they control virus replication. The high mutability of HIV-1 enables the virus to rapidly adapt, and thus evidence of viral escape is a very sensitive approach to demonstrate the importance of this response. To enable us to deconvolute ADCC escape from neutralizing antibody (nAb) escape, we identified individuals soon after infection with detectable ADCC responses, but no nAb responses. We evaluated the kinetics of ADCC and nAb responses, and viral escape, in five recently HIV-1-infected individuals. In one individual we detected viruses that escaped from ADCC responses but were sensitive to nAbs. In the remaining four participants, we did not find evidence of viral evolution exclusively associated with ADCC-mediating non-neutralizing Abs (nnAbs). However, in all individuals escape from nAbs was rapid, occurred at very low titers, and in three of five cases we found evidence of viral escape before detectable nAb responses. These data show that ADCC-mediating nnAbs can drive immune escape in early infection, but that nAbs were far more effective. This suggests that if ADCC responses have a protective role, their impact is limited after systemic virus dissemination.

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