This peptide is a 1 to 20 amino acid fragment of the interphotoreceptor retinoid binding protein (IRBP). IRBP is a 140-kDa glycolipoprotein residing in the interphotoreceptor matrix between the neural retina and the retinal pigment epithelium. Human IRBP peptide 1-20 contains a major epitope for the H-2b haplotype. Immunization with IRBP (1 – 20) induces T-cell–mediated experimental autoimmune uveoretinitis (EAU) disease. The pathology of disease induced by the peptide, or by adoptive transfer of cells specific to the peptide, is similar to that induced by the whole IRBP protein.