Project Summary Two million uveitis new cases per year occur in the United States. The current treatment strategy is to suppress the immune system with corticosteroids or other medications that have serious side effects including an increased susceptibility to infection. After a patient achieves remission for one to two years, a slow taper of the medications can be attempted, and some patients can be completely tapered off medications and maintain durable remission. There is a strong correlation between the induction of regulatory T cells (Tregs) and achieving durable remission. Unfortunately, the current medications used to treat uveitis do not induce Tregs. Therefore, treatments that target Treg induction or a cell-based approach to delivery Tregs to a patient represents a novel therapy with lasting benefits. Chimeric antigen (CAR) T cells that target B cells have been used to treat B cell lymphoma, and more recently for the treatment of B cell mediated autoimmune diseases, such as systemic lupus erythematosus. CAR Treg cells have been designed to prevent an immune response against adeno associated virus (AAV), thus allowing for more effective gene therapy. We propose to demonstrate that CAR Tregs are effective in suppressing autoimmune uveitis. Our central hypothesis is that CAR Tregs effectively suppresses ocular inflammation. We have a unique opportunity to evaluate and develop ocular CAR Tregs with the experience in the Lee lab with experimental autoimmune uveitis (EAU), and the Keeler lab that has experience developing CAR Tregs. The Keeler lab has AAV-specific CAR Tregs on hand and has shown these are effective at suppressing inflammation. Therefore, we will determine if administration of AAV-specific CAR Tregs in combination with an intraocular injection of AAV is effective in suppressing EAU (Aim 1). We will also generate ocular antigen-specific CAR Tregs and evaluate the efficacy of these Tregs to suppress EAU. Completion of this project will provide the foundation for developing a novel therapeutic for autoimmune uveitis and could further be applied to any ocular disease with an inflammatory component.