EXPERIMENTAL AUTOIMMUNE ANTERIOR UVEITIS - INDUCTION WITH MELANIN-ASSOCIATED ANTIGEN FROM THE IRIS AND CILIARY BODY

Purpose. This study was designed to investigate an animal model of uve itis that resembles anterior uveitis in humans after immunization with iris-ciliary body antigen. Methods. Male Lewis rats 6 to 8 weeks of a ge were immunized with the buffer- and detergent-insoluble bovine iris -ciliary body antigen mixed with complete Freund's adjuvant and pertus sis toxin. Antigen was digested with various proteolytic enzymes and t ested in different rodent strains for a uveitogenic response. Results. Acute iridocyclitis developed in both eyes of the Lewis rat during th e second week after immunization, and the pattern of inflammation was similar to acute anterior uveitis in humans, with sudden onset, locali zation to the anterior uvea, and spontaneous resolution. Among the str ains tested, F344 rats were susceptible to experimental autoimmune ant erior uveitis but Long-Evans rats were not. Experimental autoimmune an terior uveitis did not develop in any of the mice studied, nor was it induced by immunization with synthetic melanin, amelanotic bovine tiss ues, pigmented bovine skin, or pigmented rat and rabbit iris-ciliary b ody. A soluble fraction derived from bovine melanin-associated antigen (BMAA) after digestion with the proteolytic enzyme V8 protease result ed in a disease similar to that observed with intact BMAA. Conclusions . A model of anterior uveitis has been induced in the Lewis rat after immunization with bovine uveal antigen, and it resembles the acute iri docyclitis observed in humans. These results suggest that the pathogen ic antigen is a melanin-associated protein(s) present within the iris- ciliary body.