Abstract
Purpose: :
The purpose of this study was to induce experimental autoimmune anterior uveitis (EAAU) by melanin associated antigen (MAA - 22 kDa fragment of type I collagen alpha 2 chain) purified from rat iris and ciliary body and to localize MAA within the rat eye.
Methods: :
Iris and ciliary body harvested from the eyes of Lewis rats were used to purify MAA to homogeneity. Lewis rats were immunized with rat MAA emulsified in complete Freund’s adjuvant (CFA). T cell proliferation assay and adoptive transfer of T cells was performed to investigate the pathogenesis of EAAU induced by rat MAA. Polyclonal antibodies were raised by immunizing New Zealand White rabbits with mixture of pure MAA and CFA. These antibodies were used in immunohistochemistry and Western blot analysis to localize MAA in various organs of naïve Lewis rats.
Results: :
Lewis rats sensitized to rat MAA developed anterior uveitis in both eyes. EAAU induced by rat MAA can be adoptively transferred to naïve syngenic rats by primed T cells and animals immunized with rat MAA developed cellular immunity to the antigen. Importantly, MAA was detected only in the iris and ciliary body of the rat eye.
Conclusions: :
Our results provide compelling evidence that MAA is the target auto-antigen in EAAU. We believe that these findings may have clinical significance because the disease in EAAU model resembles human idiopathic anterior uveitis and identification of auto-antigen is critical to understand the etiology of this incurable disease as well as for the development of antigen specific therapies.
Keywords: anterior segment • autoimmune disease • ciliary body