Evaluation of target cells for HIV-1-specific antibody-dependent cellular cytotoxicity assays

1988 ◽  
Vol 115 (2) ◽  
pp. 247-253 ◽  
Author(s):  
J.A. Scheppler ◽  
A.C. Mawle ◽  
J.S. McDougal
mBio ◽  
2019 ◽  
Vol 10 (4) ◽  
Author(s):  
Benjamin von Bredow ◽  
Raiees Andrabi ◽  
Michael Grunst ◽  
Andres G. Grandea ◽  
Khoa Le ◽  
...  

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.


2019 ◽  
Vol 93 (10) ◽  
Author(s):  
Wen Shi Lee ◽  
Jérémie Prévost ◽  
Jonathan Richard ◽  
Reneé M. van der Sluis ◽  
Sharon R. Lewin ◽  
...  

ABSTRACTHIV-1-specific antibody-dependent cellular cytotoxicity (ADCC) antibodies within HIV-1-positive (HIV-1+) individuals predominantly target CD4-induced (CD4i) epitopes on HIV-1 envelope glycoprotein (Env). These CD4i epitopes are usually concealed on the surface of infected cells due to CD4 downregulation by the HIV-1 accessory proteins Nef and Vpu. We hypothesized that early-stage infected cells in the process of downregulating CD4 could be more susceptible to ADCC than late-stage infected cells that have fully downregulated CD4. There was significantly higher binding of antibodies within plasma from HIV-1-infected individuals to early-stage infected cells expressing intermediate levels of CD4 (CD4-intermediate cells) than in late-stage infected cells expressing low levels of CD4 (CD4-low cells). However, we noted that HIV-1-uninfected bystander cells and HIV-1-infected cells, at various stages of downregulating CD4, were all susceptible to NK cell-mediated ADCC. Importantly, we observed that the cytolysis of bystander cells and early infected cells in this culture system was driven by sensitization of target cells by inoculum-derived HIV-1 Env or virions. This phenomenon provided Env to target cells prior tode novoEnv expression, resulting in artifactual ADCC measurements. Future studies should take into consideration the inherent caveats ofin vitroinfection systems and develop improved models to address the potential role for ADCC against cells with nascent HIV-1 infection.IMPORTANCEAn increasing body of evidence suggests that ADCC contributes to protection against HIV-1 acquisition and slower HIV-1 disease progression. Targeting cells early during the infection cycle would be most effective in limiting virus production and spread. We hypothesized that there could be a time-dependent susceptibility of HIV-1-infected cells to ADCC in regard to CD4 expression. We observed NK cell-mediated ADCC of HIV-1-infected cells at multiple stages of CD4 downregulation. Importantly, ADCC of early infected cells appeared to be driven by a previously unappreciated problem of soluble Env and virions from the viral inoculum sensitizing uninfected cells to ADCC prior tode novoEnv expression. These results have implications for studies examining ADCC against cells with nascent HIV-1 infection.


2019 ◽  
Vol 94 (4) ◽  
Author(s):  
David Easterhoff ◽  
Justin Pollara ◽  
Kan Luo ◽  
William D. Tolbert ◽  
Brianna Young ◽  
...  

ABSTRACT Induction of protective antibodies is a critical goal of HIV-1 vaccine development. One strategy is to induce nonneutralizing antibodies (NNAbs) that kill virus-infected cells, as these antibody specificities have been implicated in slowing HIV-1 disease progression and in protection. HIV-1 Env constant region 1 and 2 (C1C2) monoclonal antibodies (MAbs) frequently mediate potent antibody-dependent cellular cytotoxicity (ADCC), making them an important vaccine target. Here, we explore the effect of delayed and repetitive boosting of RV144 vaccine recipients with AIDSVAX B/E on the C1C2-specific MAb repertoire. It was found that boosting increased clonal lineage-specific ADCC breadth and potency. A ligand crystal structure of a vaccine-induced broad and potent ADCC-mediating C1C2-specific MAb showed that it bound a highly conserved Env gp120 epitope. Thus, boosting to affinity mature these types of IgG C1C2-specific antibody responses may be one method by which to make an improved HIV vaccine with higher efficacy than that seen in the RV144 trial. IMPORTANCE Over one million people become infected with HIV-1 each year, making the development of an efficacious HIV-1 vaccine an important unmet medical need. The RV144 human HIV-1 vaccine regimen is the only HIV-1 clinical trial to date to demonstrate vaccine efficacy. An area of focus has been on identifying ways by which to improve upon RV144 vaccine efficacy. The RV305 HIV-1 vaccine regimen was a follow-up boost of RV144 vaccine recipients that occurred 6 to 8 years after the conclusion of RV144. Our study focused on the effect of delayed boosting in humans on the vaccine-induced Env constant region 1 and 2 (C1C2)-specific antibody repertoire. It was found that boosting with an HIV-1 Env vaccine increased C1C2-specific antibody-dependent cellular cytotoxicity potency and breadth.


mBio ◽  
2019 ◽  
Vol 10 (6) ◽  
Author(s):  
Franck P. Dupuy ◽  
Sanket Kant ◽  
Alexandre Barbé ◽  
Jean-Pierre Routy ◽  
Julie Bruneau ◽  
...  

ABSTRACT Measuring Envelope (Env)-specific antibody (Ab)-dependent cellular cytotoxicity (ADCC)-competent Abs in HIV+ plasma is challenging because Env displays distinctive epitopes when present in a native closed trimeric conformation on infected cells or in a CD4-bound conformation on uninfected bystander cells. We developed an ADCC model which distinguishes Env-specific ADCC-competent Abs based on their capacity to eliminate infected, bystander, or Env rgp120-coated cells as a surrogate for shed gp120 on bystander cells. A panel of monoclonal Abs (MAbs), used to opsonize these target cells, showed that infected cells were preferentially recognized/eliminated by MAbs to CD4 binding site, V3 loop, and viral spike epitopes whereas bystander/coated cells were preferentially recognized/eliminated by Abs to CD4-induced (CD4i) epitopes. In HIV-positive (HIV+) plasma, Env-specific Abs recognized and supported ADCC of infected cells, though a majority were directed toward CD4i epitopes on bystander cells. For ADCC activity to be effective in HIV control, ADCC-competent Abs need to target genuinely infected cells. IMPORTANCE HIV Env-specific nonneutralizing Abs (NnAbs) able to mediate ADCC have been implicated in protection from HIV infection. However, Env-specific NnAbs have the capacity to support ADCC of both HIV-infected and HIV-uninfected bystander cells, potentially leading to misinterpretations when the assay used to measure ADCC does not distinguish between the two target cell types present in HIV cultures. Using a novel ADCC assay, which simultaneously quantifies the killing activity of Env-specific Abs on both infected and uninfected bystander cells, we observed that only a minority of Env-specific Abs in HIV+ plasma mediated ADCC of genuinely HIV-infected cells displaying Env in its native closed conformation. This assay can be used for the development of vaccine strategies aimed at eliciting Env-specific Ab responses capable of controlling HIV infection.


2019 ◽  
Author(s):  
David Easterhoff ◽  
Justin Pollara ◽  
Kan Luo ◽  
William D. Tolbert ◽  
Brianna Young ◽  
...  

AbstractInduction of protective antibodies is a critical goal of HIV-1 vaccine development. One strategy is to induce non-neutralizing antibodies that kill virus-infected cells as these antibody specificities have been implicated in slowing HIV-1 disease progression and in protection. HIV-1 Env constant region 1 and 2 (C1C2) antibodies frequently contain potent antibody dependent cellular cytotoxicity (ADCC) making them a vaccine target. Here we explore the effect of delayed and repetitive boosting of RV144 vaccinee recipients with ALVAC/AIDSVAX B/E on the C1C2-specific antibody repertoire. It was found that boosting increased clonal lineage specific ADCC breadth and potency. A ligand crystal structure of a vaccine-induced broad and potent ADCC-mediating C1C2-specific antibody showed that it bound a highly conserved Env gp120 epitope. Thus, rationally designed boosting strategies to affinity mature these type of IgG C1C2-specific antibody responses may be one method by which to make an improved HIV vaccine with higher efficacy than seen in the RV144 trial.SignificanceOver one million people become infected with HIV-1 each year making the development of an efficacious HIV-1 vaccine an important unmet medical need. The RV144 human HIV-1 vaccine-regimen is the only HIV-1 clinical trial to date to demonstrate vaccine-efficacy. An area of focus has been on identifying ways by which to improve upon RV144 vaccine-efficacy. The RV305 HIV-1 vaccine-regimen was a follow-up boost of RV144 vaccine-recipients that occurred 6-8 years after the conclusion of RV144. Our studies focused on the effect of delayed boosting in humans on the vaccine-induced antibody repertoire. It was found that boosting with a HIV-1 Env vaccine increased antibody-mediated effector function potency and breadth.


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