PROJECT SUMMARY With the most people ever in history currently living with HIV, stopping the HIV epidemic remains imperative. Combination antiretroviral therapy (ART) limits viral replication, but is not curative. Thus, there is an urgent need to design a functional cure via elimination of the viral reservoir. Timothy Brown, aka the Berlin Patient, and Adam Castillejo, aka the London patient, were cured of HIV following leukemia-related, MHC-matched, allogeneic hematopoietic stem cell transplantation (HSCT) from a CCR5-deficient donor. While a CCR5-deficient immune system can demonstrably yield a functional HIV cure, allogeneic stem cell transplantation is not scalable to the general population and alternate approaches are needed. We have demonstrated that the CCR5-specific antibody Leronlimab can pharmacologically mimic a CCR5 deficient donor by occupying all available CCR5 molecules. In order to deliver Leronlimab as a gene therapy option, new delivery modalities are needed. Here, we are proposing to utilize our novel directed evolution technique to generate AAV vectors specific for T and B cells. These novel AAV vectors will facilitate in vivo delivery of Leronlimab expression here, but more importantly will support the future use of other anti-HIV approaches including CRISPR-Cas9, chimeric antigen receptors, and broadly neutralizing antibodies by delivering these therapeutics to the relevant immune cell type. In specific aim 1, we will generate and characterize AAV bearing capsids that target T and B cells specifically across both macaques and humans. In aim 2, we will demonstrate proof-of-concept utility of these new AAVs by delivering Leronlimab to SHIV-infected, ART suppressed macaques to determine if a functional cure can be achieved with this approach. This work would expand our knowledge of the mechanism of HIV cure by showing the utility of long-term antibody-based competitive CCR5 inhibition and establish a new set of AAV vectors to support in vivo delivery of anti-HIV therapeutics.

PROJECT NARRATIVE The development of curative approaches for HIV infection is now recognized as both a necessary and attainable goal. Hematopoietic stem cell transplantation resulting in a CCR5-deficient immune system has been shown to functionally cure HIV infection in two separate patients, but such an approach is not scalable to the general population. We propose here to develop novel AAV vectors targeted to immune system cells to support delivery of therapeutics such as HIV-targeted CRISPR-Cas9, chimeric antigen receptors, broadly neutralizing antibodies, or CCR5-blocking antibodies to mimic a CCR5-deficient immune system.