Abstract The presence of a reservoir of cells harbouring integrated, replication-competent virus that persists under long- term, fully suppressive antiretroviral therapy (ART) and the inability of the host immune responses to control the initial events of viral replication that follow ART interruption are critical barriers to curing HIV infection. Thus, novel therapeutic strategies to remove these barriers are critically needed. The overarching hypotheses of ERASE HIV are: (i) decreased and/or dysfunctional CD8+ T and NK cell antiviral functions, combined with the recently-described CD8+ T-cell-mediated transcriptional silencing of HIV, favour HIV persistence under ART and prevent the control of viremia if ART is stopped; and (ii) novel approaches to elicit effective CD8+ T-cell, NK cell, and antibody-dependent cellular cytotoxicity (ADCC) functions while inhibiting the CD8+ T-cell-mediated virus silencing will promote remission and/or eradication of HIV. The overarching goal of ERASE HIV is to identify novel mechanisms of HIV persistence and to test them in the most relevant pre-clinical animal models through mechanistically-oriented, community-supported therapeutic strategies that can be ultimately translated to cure HIV infection in humans. ERASE HIV includes three highly integrated Research Foci (RFs). RF1 is aimed at identifying the molecular and cellular mechanisms underlying the two distinct antiviral activities of CD8+ T-cells: the MHC-restricted, Ag-specific response that directly eliminates virus-infected cells, and the non-MHC restricted, non-cytolytic silencing of HIV transcription. As such, RF1 will provide the conceptual basis for the interventions tested in RF2 and RF3. RF2 will use animal models of ART-treated HIV infection to (i) restore CD8+ T and NK cell function with a combined α-IL-10 and IL-15 superagonist (N-803) strategy; (ii) target rebounding virus by using a CD4-mimetic compound (CD4mc) to enhance antibody recognition of cells expressing HIV Env and their elimination via ADCC; and (iii) determine if improving CD8 T and NK cell function via α-IL-10 and N- 803 synergizes with CD4mc to clear infected cells. RF3 will determine if suppression of the latency-promoting activity of CD8+ T-cells, coupled with N-803 and interventions to promote apoptosis (Bcl-2 inhibitors) or immune- mediated removal (CD4mc) of cells that have reactivated virus, will reduce the reservoir size. In all, we will exploit the synergy between the mechanistic data generated in RF1 and the in vivo interventions in RF2 and RF3 to validate a strategy that targets both HIV persistence during ART and HIV recrudescence after ART interruption. ERASE HIV is supported by experts in HIV advocacy (SisterLove); recognition and killing of HIV Env-expressing cells (Finzi/Sodroski); T and NK cell biology (Sekaly/Ribeiro/Deleage/Parsons); reservoir assays and latency models (Kulpa/Jones/Litchterfeld/Howell); pre-clinical animal studies (Paiardini/Silvestri/Garcia/Saez- Cirion/Keele/Kumar); mathematical modelling (Davenport); and therapeutics development (Merck and ImmunityBio) for HIV cure. We believe that the proposed mechanistically-oriented pre-clinical work will inform strategies that can be translated in clinical trials to achieve prolonged viral remission in PWH.

Narrative In ERASE HIV we have assembled a team of world leaders in HIV virology, immunology, advocacy, in vivo animal models, and drug development with the goal to define: (i) the key mechanisms regulating CD8+ T-cell- mediated antiviral functions, including cytotoxic T lymphocyte (CTL) activity and the recently described transcriptional silencing (i.e., pro-latency) effect, and (ii) the best way to manipulate these mechanisms by in vivo immune-based strategies to trigger the most effective CD8+ T-cells, NK cells, and ADCC responses to de- stabilize HIV persistence. This collaborative effort is uniquely poised to address the critical questions outlined in the proposal and to inform novel therapeutic strategies that can be translated in clinical trials to achieve viral remission and/or eradication in people living with HIV.