T-cell depletion and maintenance of the HIV-1 latent reservoir in distinct tissue compartments

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The primary challenge in curing HIV-1 is the persistence of a latent viral reservoir (LVR) in resting CD4+ (rCD4) T cells that harbor stably integrated latent HIV. Examining changes in the LVR composition is incredibly difficult due to the long half-life. Recent data show that clonal expansion of latently infected rCD4 T cells through a combination of antigenic stimulation, homeostatic proliferation, and integration site promotor disruption are major contributors to LVR maintenance. It is unclear which tissue source is the primary driver of LVR maintenance, as well as what level of contribution each of these three potential mechanisms driving proliferation may play in that process. Solid organ transplantation in people living with HIV and the associated different T cell induction strategies prescribed for prophylactic allograft rejection treatment provide a unique opportunity to examine how the LVR rebounds after a large proportion of the T cell repertoire is destroyed. The HOPE in Action HIV+ kidney organ transplantation trial provides access to >120 matched flash frozen lymph nodes (LN), renal allograft tissue, and longitudinally collected peripheral blood mononuclear cells (PBMC) from PLWH. We hypothesize that the LVR is primarily maintained through antigen stimulation of latently infected cells in micro foci within lymph nodes, which subsequently migrate into the circulation and other tissues in the body, thereby reestablishing the LVR post-T cell depletion therapy. Aim 1: Examine long-term LVR dynamics post-renal transplantation and its association with clinical outcomes. We will measure the HIV LVR annually for up to 10 years using the intact proviral DNA assay (IPDA), which distinguishes fully intact HIV from defective, deleted, and hypermutated proviral DNA, in individuals receiving transplant-related immunosuppressive drugs that are of interest to HIV cure strategies. Aim 2: Develop a tissue specific atlas of the LVR in LN, blood, and organ tissue (kidney) pre-transplantation, and examine reseeding of the circulating, LN, and kidney allograft LVR post T cell induction. We will assemble a multi-modal atlas of HIV+ LN by integrating the CODEX multiplexed immunofluorescence (mIF) platform to phenotype lymphoid cells and laser capture microdissection (LCM) and site-directed next-generation sequencing of the proviruses in cells isolated from distinct LN zones. HIV SMRTcap, a novel HIV-specific single molecule sequencing assay will provide simultaneous resolution of proviral sequences and matched integration sites, to evaluate clonality and intactness of latent provirus within the LN, PBMC and kidney. Aim 3: Determine the relative contribution of homeostatic proliferation, antigenic stimulation, and integration site promoter disruption on LVR maintenance and re-establishment post-transplant. These proposed studies will enable us to characterize the longitudinal LVR spatially, genetically, and phenotypically in multiple compartments. This project will provide critical information on feasibility and mechanisms of potential HIV cure strategies by modeling re-seeding of viral populations in kidney allograft and lymphoid tissues and determining driving mechanisms of clonal proliferation.