ABSTRACT Autoimmune uveitis is a major cause of blindness for which no cure and limited treatment options are available. We found that CUB domain-containing protein 1 (CDCP1) knockout (KO) mice are protected from experimental autoimmune uveitis (EAU) induced by adoptive transfer of pre-activated uveitogenic T cells, suggesting that CDCP1 facilitates pathogenic T cell infiltration through the blood–retina barrier (BRB) to induce EAU. In pilot mechanistic studies, we discovered that CDCP1 is selectively expressed on retinal pigmented epithelial cells (RPEs) in the retina and identified CD71, an established T cell activation marker, as a new ligand of CDCP1 in addition to CD6, another T cell marker. Stimulation with CD6 or CD71 induced CDCP1-mediated RPE cytoskeletal remodeling, a process known to impair epithelial barrier functions, and increased RPE production of IL-6, a pathogenic cytokine known to disrupt the endothelial barrier integrity. These intriguing data provide strong evidence in support of CDCP1 as a novel immunoregulator that interacts with CD6 and CD71 on T cells to facilitate pathogenic T cell infiltration through the BRB to induce EAU. Further, our data suggest that CDCP1 could be targeted for treating autoimmune uveitis. In this proposed study, we aim to use the unique reagents that we have developed or obtained in our preliminary studies to elucidate the detailed mechanisms by which CDCP1 regulates both the outer and inner BRB to facilitate T cell infiltration into the retina, and to determine the potential of CDCP1-targeted therapeutics using various conditional KO mice and our already developed anti-CDCP1 monoclonal antibodies and nanobodies. The proposed work should provide novel insights into our understanding of the pathogenesis of autoimmune uveitis and open new avenues of research in which CDCP1 is explored as a key immunoregulator and new therapeutic target for this blinding disease.