Development of anti-PD-1-targeted chimeric antigen receptors and genetic circuits to deplete viral reservoirs in the nonhuman primate model of lentiviral infection

Project summary/abstract Human immunodeficiency virus infects cells of the immune system and, if left untreated leads to the development of acquired immunodeficiency syndrome and death. With the advent of antiretrovirals, HIV infection has turned into a chronic infection. However, residual viral transcription is associated with increased risk for co-morbidities

in people with HIV infection. Programmed cell death protein 1 (PD-1) is an immune checkpoint protein expressed

on latently infected CD4 T cells and in particular T follicular helper (TFH) cells. TFH cells are located in the germinal centers and are enriched in replication-competent human immune deficiency virus 1 (HIV) provirus in people with HIV. My proposal builds upon the pre-clinical work I performed in non-human primates in which we

demonstrated that anti-PD1 chimeric antigen receptor T cells eliminated all detectable PD-1 expressing TFH cells; the first time the elimination of this reservoir of HIV has been reported. Unfortunately, it also depleted memory CD8+ T cells substantially, which led to accelerated disease progression. Provided we engineer higher safety

and specificity, the high potency of anti-PD1 CAR T cells suggest it offers promise for a functional HIV cure. The goal of the proposed project is to define the genetic architecture of a safer and more specific second-generation anti-PD-1 CAR. Aim 1 is divided in two sub aims that describe the development of first, a more specific anti-PD-

1 CAR by integrating its expression under the control of an additional TFH-specific synNotch receptor and second, a safer CAR by adding an ON switch controlled by a small molecule inhibitor. These experiments will demonstrate that a second-generation anti-PD-1 CAR is highly specific in depleting TFH cells and has the

potential to abrogate viral replication within B cell follicles more specifically, thereby providing foundational knowledge to enable further studies towards an HIV cure. My career goals are to become an assistant professor at a top-tier academic research institution. I aim to lead a research program that investigates cell therapies that

can contribute to end the HIV epidemic by providing a functional cure on an individual level, thereby decreasing the number of HIV carriers over time. To this aim, I will receive training to use a NHP lentiviral infection model in to develop next-generation HIV cure therapies, while expanding my knowledge of cell engineering. Dr. Lawrence

Corey (FHCC) will act as the primary mentor, who has substantial experience in HIV persistence, development of antiviral agents and clinical trials, while supported by an Advisory Committee with expertise in gene and cell therapies, and NHP models of HIV. I will present my work at international conferences and to my mentoring

committee. I will receive training in laboratory management/leadership, grant writing, negotiation, and mentoring to help me lead a successful research team. FHCC has superb research facilities, professional development resources and administrative support, which will provide the infrastructure to support my research and career

development as a mentored staff scientist and ultimately, my transition to independence.