Human immunodeficiency virus type-1 (HIV-1) is a retrovirus that infects CD4+ T cells of the immune system. If left untreated, HIV-1 infected individuals will progress to AIDS and may ultimately die as a result. Combination antiretroviral therapy is extremely effective at stopping the replication of HIV-1 in infected individuals. Despite the success of this therapy at suppressing HIV-1 replication to clinically undetectable levels, antiretroviral therapy is not curative. This is due to the persistence of HIV-1 in a silent, or latent, state within a subset of CD4+ T cells known as resting memory CD4+ T cells. In this latent state, these infected cells are not targeted by antiretroviral drugs and cannot be eliminated by the immune system. In HIV-1 infected individuals, latently infected CD4+ T cells are found at extremely low frequencies (~1 per million resting memory CD4+ T cells), with the majority found within immune tissues at any given time. This population of latently infected cells is very stable, demanding that HIV-1 infected individuals remain on antiretroviral therapy indefinitely to avoid rebound of viremia. As such, this population of latently infected CD4+ T cells is the main barrier to curing HIV-1 infection. Developing strategies to eliminate latently infected cells is a major focus of the NIH, NIAID, and the HIV- 1 research field. SIV and/or SHIV infected macaques are a critical non-human primate model for studying HIV- 1 persistence and testing novel therapeutic approaches. To effectively demonstrate the efficacy of candidate therapeutics targeting the latent reservoir in these animals, we must be able to measure the frequency of latently infected cells using rapid and accurate assays that can be scaled for widespread use, are amenable to analyzing both peripheral blood and processed tissues, and can be translated to human clinical studies. Accelevir Diagnostics, LLC is therefore working with the Siliciano lab at Johns Hopkins School of Medicine to developing SIV and SHIV adapted intact proviral DNA assays (IPDA) and corresponding controls for use in these critical animal studies. Broadly, the proposal aims to develop and characterize novel cell line controls for the SIV IPDA and SHIV IPDA, qualify the performance of the SIV IPDA and SHIV IPDA, and perform initial evaluation of the IPDA as a pharmacodynamic biomarker in SIV/SHIV infected macaque studies of curative interventions.
For HIV-1 infected individuals on suppressive antiretroviral therapy, latent HIV-1 infection of CD4+ T cells is the major barrier to a cure. Elimination of these latently infected cells by is being pursued as a strategy to cure the infection, and rhesus macaque models of latent HIV-1 infection that employ SIV and SHIV are critical to preclinical development. This proposal details the development and optimization of SIV and SHIV versions of a molecular assay to measure the number of latently infected cells present in biological samples for use in monitoring the efficacy of candidate cure therapies.
