Uveitis in Horses, Rats and Man: What Do We Learn from Our Pets?

The rat model of experimental autoimmune uveitis (EAU) is well established and has served for the development of new therapies in human uveitis. Uveitis in rats can be induced with a number of different autoantigens or peptides, while EAU in mice is only inducible with interphotoreceptor retinoid-binding protein (IRBP) or a single peptide of IRBP. For a long time the rat model was regarded as acute and monophasic, thus therapeutic interventions had to precede the induction of the disease by immunization or adoptive transfer of activated, autoantigen-specific T cells. Only recently spontaneous relapsing-remitting disease, induced with a peptide derived from IRBP, was detected in rats. Some years ago we have introduced the horse as a new animal model for uveitis: horses frequently have spontaneous uveitis (Equine Recurrent Uveitis, ERU) and will also develop the disease after immunization with retinal autoantigens. This offers the opportunity to directly compare spontaneous and induced diseases in the same species, which show high identities. Comparing different species, we found similarities between horses, rats, mice and humans with respect to the antigen-specificity of T cell responses, course of disease and histology. Proteomics of healthy and diseased equine eyes offered an insight of intraocular alterations during inflammation, which might be representative for uveitis in general.