Autoimmune uveitis induced by molecular mimicry of peptides from rotavirus, bovine casein and retinal S-antigen.

Antigenic mimicry of infectious agents and autoantigens is a proposed pathomechanism for autoimmune diseases. Here, we describe antigenic mimicry of a peptide from rotavirus, a nutritional protein from bovine milk (alphas2-casein) and a peptide thereof as well as a highly pathogenic peptide from retinal S-antigen (PDSAg), a major autoantigen in experimental autoimmune uveitis in Lewis rats. Immunization of rats with the peptides and the casein protein induced uveitis, an intraocular inflammation leading to decreased vision and even blindness. The peptides elicited cross-reactive T cell responses and uveitis in rats and were also recognized by lymphocytes and sera from uveitis patients. Oral tolerization with PDSAg, but not with rotavirus- and casein-derived peptides or casein protein, prevented PDSAg-induced uveitis in rats. Cofeeding of casein with cholera toxin induced uveitis in rats, suggesting that breaking oral tolerance to casein during gastrointestinal infections might also be able to initiate uveitis in humans.