OVERALL: Leaving, Coming, and Staying HIV Obligate Microenvironments (HOME) ABSTRACT Viral, host and environmental mechanisms governing HIV reservoir dynamics on and off antiretroviral therapy (ART) must be grasped more deeply if cure efforts are to be successful. Further, variability in the size, distribution and activity of the reservoir is substantial, and although a ‘one size fit all’ HIV cure strategy is seducing, a reductionist ‘bulk’ approach cannot fully capture the complex underlying processes of HIV reservoir dynamics. To better define the viral, host and environmental factors that govern these dynamics at the cellular and single- genome level, our novel Leaving, Coming and Staying HIV Obligate MicroEnvironments (HOME) program builds on our previous infrastructure, and success, including our ‘Last Gift’ cohort, which enrolls altruistic people with HIV (PWH) who did or did not stop ART before death, collects pre-mortem clinical data and limited samples, then performs a full body rapid autopsy with sample collection across the body within 6 hours of death. The rationale for our program is that the use of new single-cell and single-genome technologies will bring new perspectives on assumptions built on bulk technologies and help identify vulnerabilities in HIV reservoir states: • Leaves HOME when HIV (re)activates from tissues during ART (i.e., ‘ready to move once ART is interrupted’, like packing its bag and getting ready to leave) and causes rebound viremia during ART interruption. • Comes HOME when HIV (re)populates tissues during viremia off ART and through the spread of clonally expanded HIV-infected cells while on ART. (Clonal expansion is like adding family to the home.) • Stays HOME when HIV persists in tissue reservoirs during ART and viral suppression in plasma. The HOME program is organized into three Research Projects (RP) to investigate these reservoir dynamics: • The Viral, EpigeNetics and Integration (VENI) RP will investigate viral and proviral epigenetic factors. • The Viral, Immunology, Drugs, and Imaging (VIDI) RP will investigate host and environmental factors. • The Viral, Immune, and Cellular data Integration (VICI) RP will develop new methods needed for the integration and analysis of complex multi-dimensional data. These three RPs will be supported by two cores: the Administrative and Data (AD) Core will provide leadership, communication and data services, and the Clinical, Outreach, Pathology and Ethics (COPE) Core will direct and ethically oversee the Last Gift cohort. Our proposed HOME program is a good use of resources because it innovatively responds directly to the Understanding HIV Reservoir Dynamics RFA (AI-21-013) and will create the next level of understanding of deep HIV reservoirs. We expect to clearly define the viral, immunological, cellular expression, epigenetic, tissue architectural factors associated with specified HIV reservoir states across the human body on and off ART. Such results would be foundational for HIV cure strategies aimed at locking down or clearing HIV reservoirs.

NARRATIVE Our HOME program is designed to be directly responsive to the Understanding HIV Reservoir Dynamics RFA (RFA-AI-21-013) to define how HIV colonizes, establishes, and moves within and across reservoirs with different immune, cell, epigenetic and HIV drug environments. This program will provide new knowledge on the fundamental viral and host mechanisms driving HIV reservoir dynamics and identify the vulnerabilities in the activity and renewal of HIV reservoirs across the human body that can be targeted by new HV cure efforts.