Measuring the contribution of γδ T cells to the persistent HIV reservoir

Objective:To study the contribution of γδ T cells to the persistent HIV reservoir.Design:Fifteen HIV-seropositive individuals on suppressive ART were included. We performed parallel quantitative viral outgrowth assays (QVOA) of resting CD4+ T (rCD4) cells in the presence or absence of γδ T cells.Methods:Resting αβ+CD4+ T cells were magnetically isolated from PBMCs using two different custom cocktails, only one kit contained antibodies to deplete γδ T cells, resulting in two populations: rCD4 cells and rCD4 cells depleted of γδ cells. Frequency of infection was analyzed by QVOA and DNA measurements.Results:Recovery of replication-competent HIV from cultures of rCD4 cells was similar in 11 individuals despite the presence of γδ T cells. In four donors, HIV recovery was lower when γδ T cells were present. Expression of the cytotoxic marker CD16+ on Vδ2 cells was the only variable associated with the lower HIV recovery. Our results highlight the potency of those responses since a mean of 10000 γδ T cells were present within 2.5 million rCD4 cells. However, despite the low frequency of γδ T cells, the presence of cytotoxic Vδ2 cells correlated with lower HIV recovery from cultures of rCD4 cells.Conclusion:Results of this study show that quantification of the contribution of γδ T cells to the reservoir is challenging because of their low numbers compared with conventional rCD4 cells and highlights the potent antiviral function of γδ T cells and the impact of their presence on the frequency of latent HIV infection

HIV-Specific T Cells Generated from Naive T Cells Suppress HIV In Vitro and Recognize Wide Epitope Breadths

The Berlin Patient represents the first and only functional HIV cure achieved by hematopoietic stem cell transplant (HSCT). In subsequent efforts to replicate this result, HIV rebounded post-HSCT after withdrawal of antiretroviral therapy. Providing HIV-specific immunity through adoptive T cell therapy may prevent HIV rebound post-HSCT by eliminating newly infected cells before they can seed systemic infection. Adoptive T cell therapy has demonstrated success in boosting Epstein-Barr virus and cytomegalovirus-specific immunity post-HSCT, controlling viral reactivation. However, T cell immunotherapies to boost HIV-specific immunity have been limited by single-epitope specificity and minimal persistence or efficacy in vivo. To improve this strategy, we sought to generate allogeneic HIV-specific T cells from human leukocyte antigen (HLA)-A02+ HIV-negative adult or cord blood donors. We focused on HLA-A02+ donors due to well-characterized epitope restrictions observed in HIV+ populations. We show that multi-antigen HIV-specific T cells can be generated from naive T cells of both cord blood and adults using a reproducible good manufacturing practice (GMP)-grade protocol. This product lysed antigen-pulsed targets and suppressed active HIV in vitro. Interestingly, these cells displayed broad epitope recognition despite lacking recognition of the common HLA-A02-restricted HIV epitope Gag SL9. This first demonstration of functional multi-antigen HIV-specific T cells has implications for improving treatment of HIV through allogeneic HSCT. Patel et al. demonstrate the ability to generate HIV-specific T cells from HIV-seronegative adults and cord blood with a good-manufacturing-practice-compliant strategy. These immunotherapies are multi-antigen specific, display cytotoxicity, and suppress HIV in vitro, providing a promising platform for adoptive T cell therapy in a post-transplant setting

Aminobisphosphonates reactivate the latent reservoir in people living with HIV-1

Antiretroviral therapy (ART) is not curative due to the existence of cellular reservoirs of latent HIV-1 that persist during therapy. Current research efforts to cure HIV-1 infection include “shock and kill” strategies to disrupt latency using small molecules or latency-reversing agents (LRAs) to induce expression of HIV-1 enabling cytotoxic immune cells to eliminate infected cells. The modest success of current LRAs urges the field to identify novel drugs with increased clinical efficacy. Aminobisphosphonates (N-BPs) that include pamidronate, zoledronate, or alendronate, are the first-line treatment of bone-related diseases including osteoporosis and bone malignancies. Here, we show the use of N-BPs as a novel class of LRA: we found in ex vivo assays using primary cells from ART-suppressed people living with HIV-1 that N-BPs induce HIV-1 from latency to levels that are comparable to the T cell activator phytohemagglutinin (PHA). RNA sequencing and mechanistic data suggested that reactivation may occur through activation of the activator protein 1 signaling pathway. Stored samples from a prior clinical trial aimed at analyzing the effect of alendronate on bone mineral density, provided further evidence of alendronate-mediated latency reversal and activation of immune effector cells. Decay of the reservoir measured by IPDA was however not detected. Our results demonstrate the novel use of N-BPs to reverse HIV-1 latency while inducing immune effector functions. This preliminary evidence merits further investigation in a controlled clinical setting possibly in combination with therapeutic vaccination