Although modern therapies have improved the outlooks for people living with HIV/AIDS (PLWHA) they are unable to cure infection, leaving these individuals burdened by a lifelong commitment to expensive antiretroviral medication. It has also become clear that these treatments do not fully restore health, nor do they address the negative social issues associated with being HIV positive. The development of a safe and effective HIV cure would thus greatly improve the lives of PLWHA. A major obstacle to curing HIV infection is the establishment of reservoirs of hidden or ‘latent’ virus which evade the immune system and can re-seed infection if an individual stops antiretroviral therapy. Efforts are underway to attempt to purge these HIV reservoirs. There is theoretically achievable by combining ‘latency reversing agents’ (LRAs) capable of exposing hidden virus with immune effectors such as killer T-cells that can then eliminate these cells, the so-called ‘shock and kill’ approach. The viability of the shock and kill strategy is supported by in vitro experiments using cell line models of latency, where combinations of LRAs with killer T-cells can reduce HIV reservoirs. However, clinical trials that have attempted to achieve this in vivo have yielded disappointing results. In preliminary studies, we have attempted to bridge this gap by determining if combinations of LRAs with killer T-cells could eliminate HIV from patient CD4+ T-cell samples in vitro. We made the surprising observation that this consistently resulted in the elimination of the defective HIV proviruses that make up the majority of HIV DNA, without impacting the intact inducible proviruses that need to be eliminated to cure infection. In the current project we propose the testing of different combinations of HIV-specific killer T-cells and LRAs in this assay, in the hopes of identifying combinations that are able to more effectively target intact inducible proviruses. Our study design will allow us to identify general features of both killer T-cells and of LRAs that are associated with effective elimination of intact inducible proviruses. In the process of perturbing these natural HIV reservoirs, we will also test a wide range of reservoir measurement assays to determine which best reflect depletions in intact inducible proviruses versus of total/defective proviruses. Our study will thus provide critical guidance both for the design of interventions aimed at curing HIV infection in future clinical trials, and for the selection and interpretation of reservoir measurement assays to be used in these studies.

Project Narrative Although HIV infection can be controlled by daily lifelong adherence to expensive antiretroviral therapies it cannot presently be cured. The ‘shock and kill’ approach aims to combine immune effectors with latency reversing agents to eliminate persistent HIV reservoirs, thus curing infection. We propose addressing a missing proof of principle for this approach by extensively testing the shock and kill approach against natural HIV reservoirs from cells of participants ex vivo. In the process, we hope to identify the features of immune effectors that are critical to achieving complete eradication of infectious reservoirs, providing critical guidance to future clinical trials aimed at curing infection.