Reducing the HIV Reservoir: Next-Generation Latency Reversal Agents and T Cell Population Targets

PROJECT SUMMARY/ABSTRACT
The human immunodeficiency virus (HIV) is responsible for major morbidity, mortality, and cost to
healthcare systems worldwide. While antiretroviral therapy (ART) provides a potent reduction of viremia and
improvement in immune function, lifelong adherence is required to prevent viral rebound from the viral
reservoir—latent, but replication competent proviral HIV DNA in the genomes of host CD4 T cell lymphocytes.
Significantly, a lifetime of treatment is associated with financial burden, drug interactions, drug resistance, and
unknown long-term effects of treatment. Furthermore, the stigma associated with HIV disease contributes to
negative health outcomes. Thus, a cure for HIV is of substantial public health interest.
A main strategy for HIV cure is the use of small-molecule latency reversal agents (LRAs) to induce viral
expression in the latent reservoir so that the immune system can recognize and clear the reservoir. This viral
reservoir is best understood within resting CD4 T lymphocytes. However, the nature of HIV persistence in other
CD4 T cell populations (“non-resting”) is unknown. Understanding HIV persistence in non-resting CD4 T cells
is important to determine whether exogenous interventions are necessary to deplete these cells in cure
strategies. Thus, in AIM 1, we will characterize persistent HIV in resting versus non-resting CD4 T cells
from ART-suppressed HIV seropositive participants using cell sorting, an array of viral reservoir measurement
techniques, ultrasensitive antigen detection assays, and near-full length viral genome sequencing.
In an effort to deplete the viral reservoir, several LRAs have been tested in clinical studies. However,
LRAs used clinically to date only provide a small induction of viral expression, and none have depleted the
reservoir. More potent next-generation LRAs are in development, however, the ability of these novel LRAs to
induce sufficient viral protein expression in CD4 T cells for immune recognition and clearance is not well-
defined. In addition, it is unknown whether non-resting CD4 T cells, despite being more transcriptionally active
than resting CD4 T cells, can undergo spontaneous immune clearance without an LRA or if these cells
represent another compartment of HIV persistence. Thus, in AIM 2 we will assess the ability of novel and
potent next-generation LRAs to induce HIV expression sufficient for immune clearance in resting
versus non-resting CD4 T cells using the techniques described above and a novel latency clearance assay.
In addition to informing future efforts in HIV cure research, the project proposed herein fits perfectly into
an intensive training plan for a productive clinician scientist at a top-tier research university. The pioneering
environment of the UNC HIV Cure Center and the sponsors, David Margolis, MD and Nancie Archin, PhD will
provide the mentorship necessary for the development of an outstanding clinician scientist in the HIV field.