Rapamycin Enhances CAR-T Control of HIV Replication and Reservoir Elimination in vivo 3825

Abstract Description Chimeric Antigen Receptor (CAR) T cell therapy shows promise for various diseases. Our studies in humanized mice and non-human primates (NHPs) demonstrate that hematopoietic stem cell (HSCs) modified with anti-HIV CAR achieve lifelong engraftment, providing functional anti-viral CAR-T cells that reduce viral rebound after ART withdrawal. However, T cell exhaustion due to chronic immune activation remains a key obstacle for sustained CAR-T efficacy, necessitating additional measures to achieve functional cure. We recently showed that low dose rapamycin treatment reduces inflammation and enhances anti-HIV T cell function in humanized mice. Here, we report that rapamycin improved CAR-T cell function both in vitro and in vivo. In vitro treatment with rapamycin enhanced CAR-T cell mitochondria respiration and cytotoxicity. In vivo treatment with low-dose rapamycin in HIV-infected, CAR-HSC mice decreased chronic inflammation, prevented exhaustion of CAR-T cells and improved CAR-T control of viral replication. RNAseq analysis of CAR-T cells from humanized mice showed that rapamycin downregulated multiple checkpoint inhibitors and upregulated key survival genes. Mice treated with CAR-HSCs and rapamycin had delayed viral rebound post-ART and reduced HIV reservoir compared to CAR-HSCs alone. These findings suggest that HSCs-based anti-HIV CAR-T combined with rapamycin treatment is a promising approach for treating persistent inflammation and improving immune control of HIV replication. Funding Sources Supported by NIH (grant 1R21AI140866, R01AI172727, U19AI149504, P30AI28697, 1R01CA239261-01, and R01DA-52841), American Foundation for AIDS Research (grant 110304-71-RKRL, 10395-72-RPRL, 109577-62-RGRL and 110038-67-RSRL), California Institute for Regenerative Medicine (grant TRAN1-14625), California HIV/AIDS Research Program (grant H24BD7817). Topic Categories Viral Immunology (VIR)