Uveitogenic proteins isolated from bovine iris and ciliary body.

Experimental autoimmune anterior uveitis (EAAU) is an animal model for acute anterior uveitis in humans. Previously, we have shown that EAAU can be induced in Lewis rats by a protein(s) associated with ocular melanin. The present study was designed to further purify the pathogenic antigen. Melanin associated antigen (MAA), isolated from bovine iris and ciliary body, was digested with V8 protease and the soluble protein separated on a cation exchange column. The bound protein was eluted with a salt gradient. Lewis rats were immunised with the resulting fractions to test for pathogenicity. Moderate to severe EAAU, with clinical and histopathological features similar to induction with crude soluble bovine MAA, was observed with the 100-200 mM gradient of NH4Cl. Thus, bovine MAA has been partially purified using cation exchange chromatography. Studies are currently under way to purify bovine MAA to homogeneity.