Pre-existing infant antibody-dependent cellular cytotoxicity associates with reduced HIV-1 acquisition and lower morbidity

ABSTRACTAs a consequence of their independent evolutionary origins in apes and Old World monkeys, human immunodeficiency virus type 1 (HIV-1) and simian immunodeficiency viruses of the SIVsmm/maclineage express phylogenetically and antigenically distinct envelope glycoproteins. Thus, HIV-1 Env-specific antibodies do not typically cross-react with the Env proteins of SIVsmm/macisolates. Here we show that PGT145, a broadly neutralizing antibody to a quaternary epitope at the V2 apex of HIV-1 Env, directs the lysis of SIVsmm/mac-infected cells by antibody-dependent cellular cytotoxicity (ADCC) but does not neutralize SIVsmm/macinfectivity. Amino acid substitutions in the V2 loop of SIVmac239 corresponding to the epitope for PGT145 in HIV-1 Env modulate sensitivity to this antibody. Whereas a substitution in a conserved N-linked glycosylation site (N171Q) eliminates sensitivity to ADCC, a lysine-to-serine substitution in this region (K180S) increases ADCC and renders the virus susceptible to neutralization. These differences in function correlate with an increase in the affinity of PGT145 binding to Env on the surface of virus-infected cells and to soluble Env trimers. To our knowledge, this represents the first instance of an HIV-1 Env-specific antibody that cross-reacts with SIVsmm/macEnv and illustrates how differences in antibody binding affinity for Env can differentiate sensitivity to ADCC from neutralization.IMPORTANCEHere we show that PGT145, a potent broadly neutralizing antibody to HIV-1, directs the lysis of SIV-infected cells by antibody-dependent cellular cytotoxicity but does not neutralize SIV infectivity. This represents the first instance of cross-reactivity of an HIV-1 Env-specific antibody with SIVsmm/macEnv and reveals that antibody binding affinity can differentiate sensitivity to ADCC from neutralization.

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Antibody-Induced Internalization of HIV-1 Env Proteins Limits Surface Expression of the Closed Conformation of Env

Journal of Virology ◽

10.1128/jvi.00293-19 ◽

2019 ◽

Vol 93 (11) ◽

Cited By ~ 10

Author(s):

Sai Priya Anand ◽

Jonathan R. Grover ◽

William D. Tolbert ◽

Jérémie Prévost ◽

Jonathan Richard ◽

...

Keyword(s):

Immune Responses ◽

Envelope Glycoprotein ◽

Neutralizing Antibodies ◽

Surface Expression ◽

Cellular Cytotoxicity ◽

Antibody Dependent Cellular Cytotoxicity ◽

Broadly Neutralizing Antibodies ◽

Closed Conformation ◽

Infected Cells ◽

Hiv 1

ABSTRACT To minimize immune responses against infected cells, HIV-1 limits the surface expression of its envelope glycoprotein (Env). Here, we demonstrate that this mechanism is specific for the Env conformation and affects the efficiency of antibody-dependent cellular cytotoxicity (ADCC). Using flow cytometry and confocal microscopy, we show that broadly neutralizing antibodies (bNAbs) targeting the “closed” conformation of Env induce its internalization from the surface. In contrast, non-neutralizing antibodies (nNAbs) are displayed on the cell surface for prolonged period of times. The bNAb-induced Env internalization can be decreased by blocking dynamin function, which translates into higher susceptibilities of infected cells to ADCC. Our results suggest that antibody-mediated Env internalization is a mechanism used by HIV-1 to evade immune responses against the “closed” conformation of Env expressed on HIV-1-infected cells. IMPORTANCE HIV-1 has evolved to acquire several strategies to limit the exposure of its envelope glycoproteins (Env) on the surface of infected cells. In this study, we show that antibody-induced Env internalization is conformation specific and reduces the susceptibility of infected cells to antibody-dependent cellular cytotoxicity (ADCC). Thus, a better understanding of this mechanism might help develop antibodies with improved capacities to mediate ADCC.

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Antibody-dependent cellular cytotoxicity-mediating antibodies from an HIV-1 vaccine efficacy trial preferentially use the VH1 gene family

Retrovirology ◽

10.1186/1742-4690-9-s2-p78 ◽

2012 ◽

Vol 9 (S2) ◽

Author(s):

M Bonsignori ◽

J Pollara ◽

MA Moody ◽

TB Kepler ◽

X Chen ◽

...

Keyword(s):

Gene Family ◽

Vaccine Efficacy ◽

Cellular Cytotoxicity ◽

Antibody Dependent Cellular Cytotoxicity ◽

Efficacy Trial ◽

Hiv 1

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Antiphosphatidylserine antibodies in human immunodeficiency virus-1 patients with evidence of T-cell apoptosis and mediate antibody- dependent cellular cytotoxicity [see comments]

Blood ◽

10.1182/blood.v87.12.5185.bloodjournal87125185 ◽

1996 ◽

Vol 87 (12) ◽

pp. 5185-5195 ◽

Cited By ~ 28

Author(s):

F Silvestris ◽

MA Frassanito ◽

P Cafforio ◽

D Potenza ◽

M Di Loreto ◽

...

Keyword(s):

Human Immunodeficiency Virus ◽

T Cell ◽

Cell Apoptosis ◽

Clinical Feature ◽

Enzyme Linked Immunosorbent Assay ◽

Cellular Cytotoxicity ◽

Antibody Dependent Cellular Cytotoxicity ◽

T Cell Apoptosis ◽

Immunodeficiency Virus ◽

Hiv 1

Serum reactivities to a panel of phospholipid antigens, including cardiolipin (CL), phosphatidylserine (PS), sphingomyelin, phosphatidylcholine, and phosphatidylethanolamine, were measured by enzyme-linked immunosorbent assay in 196 human immunodeficiency virus- l+ (HIV-1+) patients with CDC II to IVC clinical disease. Significant levels of IgG to CL, PS, or both were observed in 23 patients lacking evidence of thrombophilic events or any peculiar clinical feature of HIV-1 infection. Fluorescence-activated cell sorting analyses showed that in vitro apoptosis of T cells was increased in patients with high serum anti-PS IgG, whereas the overexpression of Fas/Apo-1 marker was detected in all patients regardless of their antiphospholipid reactivities. Macrophages from patients with significant titers of anti- PS IgG antibodies were not activated by the presence of apoptotic CEM lymphoblasts or by purified anti-PS IgG from the same patients. By contrast, these antibodies greatly improved the effector functions of autologous macrophages in antibody-dependent cellular cytotoxicity (ADCC) assays using 51Cr-labeled CEM cells, whereas polyspecific IgG were unable to induce an equivalent cytotoxicity in all instances. An increasing effect on ADCC was also observed in tests using macrophages from healthy controls to CEM coated with anti-PS IgG. These results support a potential correlation of anti-PS specificity with T-cell apoptosis in HIV-1 infection. Because PS is exteriorized by apoptotic lymphocytes, its persistence may stimulate antibodies which cooperate with macrophages in the clearance of dead cells by an enhanced ADCC mechanism. This interpretation could explain the absence of thrombophilia in HIV-1+ patients with serum elevations of antiphospholipid reactivities.

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Low antibody-dependent cellular cytotoxicity responses in Zambians prior to HIV-1 intrasubtype C superinfection

Virology ◽

10.1016/j.virol.2014.06.016 ◽

2014 ◽

Vol 462-463 ◽

pp. 295-298 ◽

Cited By ~ 5

Author(s):

Debby Basu ◽

Peng Xiao ◽

Zachary Ende ◽

Alfred Bere ◽

William J. Britt ◽

...

Keyword(s):

Cellular Cytotoxicity ◽

Antibody Dependent Cellular Cytotoxicity ◽

Hiv 1

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Uninfected Bystander Cells Impact the Measurement of HIV-Specific Antibody-Dependent Cellular Cytotoxicity Responses

mBio ◽

10.1128/mbio.00358-18 ◽

2018 ◽

Vol 9 (2) ◽

Cited By ~ 35

Author(s):

Jonathan Richard ◽

Jérémie Prévost ◽

Amy E. Baxter ◽

Benjamin von Bredow ◽

Shilei Ding ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Ex Vivo ◽

Cellular Cytotoxicity ◽

Antibody Dependent Cellular Cytotoxicity ◽

Antibody Recognition ◽

Vaccine Trials ◽

Infected Cells ◽

Bystander Cells ◽

Hiv 1

ABSTRACTThe conformation of the HIV-1 envelope glycoprotein (Env) substantially impacts antibody recognition and antibody-dependent cellular cytotoxicity (ADCC) responses. In the absence of the CD4 receptor at the cell surface, primary Envs sample a “closed” conformation that occludes CD4-induced (CD4i) epitopes. The virus controls CD4 expression through the actions of Nef and Vpu accessory proteins, thus protecting infected cells from ADCC responses. However, gp120 shed from infected cells can bind to CD4 present on uninfected bystander cells, sensitizing them to ADCC mediated by CD4i antibodies (Abs). Therefore, we hypothesized that these bystander cells could impact the interpretation of ADCC measurements. To investigate this, we evaluated the ability of antibodies to CD4i epitopes and broadly neutralizing Abs (bNAbs) to mediate ADCC measured by five ADCC assays commonly used in the field. Our results indicate that the uninfected bystander cells coated with gp120 are efficiently recognized by the CD4i ligands but not the bNabs. Consequently, the uninfected bystander cells substantially affectin vitromeasurements made with ADCC assays that fail to identify responses against infected versus uninfected cells. Moreover, using an mRNA flow technique that detects productively infected cells, we found that the vast majority of HIV-1-infected cells inin vitrocultures orex vivosamples from HIV-1-infected individuals are CD4 negative and therefore do not expose significant levels of CD4i epitopes. Altogether, our results indicate that ADCC assays unable to differentiate responses against infected versus uninfected cells overestimate responses mediated by CD4i ligands.IMPORTANCEEmerging evidence supports a role for antibody-dependent cellular cytotoxicity (ADCC) in protection against HIV-1 transmission and disease progression. However, there are conflicting reports regarding the ability of nonneutralizing antibodies targeting CD4-inducible (CD4i) Env epitopes to mediate ADCC. Here, we performed a side-by-side comparison of different methods currently being used in the field to measure ADCC responses to HIV-1. We found that assays which are unable to differentiate virus-infected from uninfected cells greatly overestimate ADCC responses mediated by antibodies to CD4i epitopes and underestimate responses mediated by broadly neutralizing antibodies (bNAbs). Our results strongly argue for the use of assays that measure ADCC against HIV-1-infected cells expressing physiologically relevant conformations of Env to evaluate correlates of protection in vaccine trials.

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