CD4-mimetics sensitize HIV-infected cells to ADCC mediated by plasma from persons with early-stage HIV-1 infection.

The viral reservoir in long-lived memory CD4+ cells, established in the early stages of HIV infection, represents the main obstacle to an HIV cure. Some strategies being developed to target the reservoir rely on rendering HIV-1 envelope glycoproteins (Env) visible to the immune system. Small molecule CD4-mimetics (CD4mcs) expose vulnerable Env epitopes, which can be targeted by non-neutralizing antibodies (nnAbs) that are abundant in the plasma of people living with HIV (PLWH) and can mediate antibody-dependent cellular cytotoxicity (ADCC). Administration of CD4mcs in combination with plasma from PLWH or nnAbs efficiently reduces the size of the HIV-1 reservoir and postpones viral rebound upon antiretroviral therapy (ART) interruption in humanized mice. However, it remains unclear when these nnAbs are elicited after HIV infection. In this study, we collected longitudinal plasma samples before acquisition, at diagnosis, and at multiple time points up to 33 weeks after the estimated date of detectable infection (EDDI) and before ART treatment initiation. We found that plasma samples collected as early as 3 to 10 weeks after EDDI neutralized viral particles and mediated ADCC in the presence of the CJF-III-288 CD4mc. Recognition of HIV-1-infected cells and ADCC progressively increased over time, reaching a plateau by 19-25 weeks after EDDI. ADCC activity increased concomitantly with the elicitation of anti-gp120 and anti-gp41 CD4-induced (CD4i) Abs and improved over time with the appearance of anti-coreceptor binding site antibodies. Our results show that CD4i nnAbs, able to eliminate HIV-1-infected cells in the presence of CD4mc, are elicited within a few weeks after HIV acquisition. IMPORTANCE: A viral reservoir is established at the early stages of HIV-1 infection. This reservoir persists during antiretroviral therapy (ART) treatment, and viral rebound is observed after ART interruption. New strategies are needed to reduce the size of the viral reservoir and prevent virus rebound. Several families of non-neutralizing antibodies, which are abundant in plasma from people living with HIV-1, neutralize viral particles and mediate the elimination of HIV-1-infected cells through antibody-dependent cellular cytotoxicity (ADCC) when combined with CD4-mimetic compounds. The presence of non-neutralizing antibodies in plasma during early-stage HIV-1 infection would support the use of CD4-mimetic compounds as an early intervention to decrease the size of the latent HIV-1 reservoir by eliminating infected cells.