Dual CD4-based CAR T cells with distinct costimulatory domains mitigate HIV pathogenesis in vivo

Abstract

A potent and sustained antiviral T cell response will likely be a critical component of an effective HIV cure strategy. Here, we explored the utility of CD4-based Chimeric Antigen Receptor (CAR) T cells to mitigate HIV-induced pathogenesis in BLT humanized mice. CAR T cells expressing the archetypal 4-1BB/CD3- endodomain were insufficient to prevent viral rebound and CD4+ T cell loss after the discontinuation of antiretroviral therapy (ART). Through iterative in vivo improvements to the CAR T cell product, we developed Dual-CAR T cells that independently expressed both 4-1BB/CD3- and CD28/CD3- endodomains. Dual-CAR T cells exhibited expansion kinetics that exceeded 4-1BB-, CD28- and 3rd-generation costimulated CAR T cells, elicited effector functions equivalent to CD28-costimulated CAR T cells, and prevented HIV-induced CD4+ T cell loss despite persistent viremia. Moreover, when Dual-CAR T cells were protected from HIV infection through expression of the C34-CXCR4 fusion inhibitor these cells significantly reduced acute phase viremia, as well as accelerated HIV suppression in the presence of ART and reduced tissue viral burden. Collectively, these studies demonstrate the enhanced potency of a novel Dual-CAR T cell product, highlighting the therapeutic potential of engineered T cells to effectively treat HIV infection.