Molecular mimicry. Yeast histone H3-induced experimental autoimmune uveitis.

Experimental autoimmune uveitis (EAU) serves as an animal model of ocular inflammation. The disease is caused by the immunization with microgram amounts of a soluble retinal protein, designated S-Ag, in susceptible animal strains, including primates. We induced EAU and pinealitis in Lewis rats with a small synthetic peptide, corresponding to amino acid positions 106 to 121 in yeast histone H3, which contains five consecutive amino acids identical to a uveitopathogenic site in human S-Ag. In addition, native yeast histone was also capable of inducing an EAU in Lewis rats. Lymph node cells from animals immunized with either peptide M (uveitopathogenic site of S-Ag), histone H3 peptide, or native histone showed significant cross-reaction. Also, we adoptively transferred the EAU in naive rats by lymph node cells. These findings provide a basis for studying autoimmune inflammatory diseases of the eye in humans.