Inhibition of interphotoreceptor retinoid-binding protein-induced uveitis by monoclonal antibodies

Immunization of Lewis rats with interphotoreceptor retinoid-binding protein (IRBP) resulted in development of uveoretinitis in 100% (12/12) of the animals so injected. In the present study, we attempted immunotherapy of this intraocular inflammation using the monoclonal antibodies anti-I-A and anti-I-E. The antibodies were injected 1 day before and on days 1 and 2 after IRBP sensitization, and the animals were killed 16 days later. Anti-I-A treatment inhibited the disease in 83% (10/12) of the animals, while anti-I-E antibodies resulted in inhibition of the disease in 67% (8/12) of the animals. All rats injected with preimmune IgG (control animals) developed uveoretinitis. The anti-I-A and anti-I-E antibodies exerted a specific suppressor effect on the immune response of these animals. Thus, anti-I-A and anti-I-E antibodies administered at the time of antigen priming abolished the immune function and inhibited the development of autoimmune uveitis.

Antigen-specific suppressor cells in experimental autoimmune uveitis

Anti-I-A antibodies, administered in vivo at the time of S-antigen injection, suppress development of experimental autoimmune uveitis (EAU) in Lewis rats. While the effects of anti-I-A are profound, the exact mechanism for this suppression is unknown. We attempted adoptive transfer of this form of suppression by injecting lymphocytes from anti-I-A-treated animals into syngeneic recipients which were later injected with S-antigen. Histologically, globes of 75% of the anti-I-A-treated animals showed no inflammation while 25% of these animals developed mild uveitis. In the group of animals which were injected with S-antigen and also received spleen cells from anti-I-A-treated rats, only 1 showed mild uveitis while the remaining 7 had no inflammation. The animals undergoing adoptive transfer of spleen cells and which were primed with an irrelevant antigen, readily developed uveitis. Suppression of S-antigen-induced EAU was abrogated by pretreatment of donor animals with cyclophosphamide. In vitro studies revealed that spleen cells of S-antigen-primed, anti-I-A-treated donors specifically suppressed lymphocyte responses to S-antigen. These in vivo and in vitro results suggest that generation of antigen-specific suppressor cells play a role in the anti-I-A immunotherapy of EAU.

Inhibition of autoimmune uveitis by anti-CD4 antibody

In this study, rats with S-antigen-induced uveitis were treated with W3/25, a monoclonal antibody that recognizes the CD4 molecule expressed by helper/inducer cells. Treatment was started on day 5 after administration of S-antigen. Groups of animals were killed 18 or 31 days after S-antigen injection. The enucleated globes were studied histologically, and in vitro T-cell response and anti-S antibody levels were determined. Results showed that the antibody treatment prevented development of experimental autoimmune uveitis (EAU) in all animals. Furthermore, there was no evidence of disease development for 14 days after cessation of therapy. These results suggest that CD4+ cells are important in the initiation of EAU, and that monoclonal antibodies directed to this subset may provide effective treatment of autoimmune uveal inflammation.

Suppression of experimental uveitis in rats by anti-I-A antibodies

I-region-associated (Ia) class II major histocompatibility complex (MHC) products are known to play a major role in autoimmunity. Effects of anti-I-A and anti-I-E monoclonal antibodies on development of experimental autoimmune uveitis (EAU) were investigated in Lewis rats. Prior to sensitization with S-antigen, seven groups of rats, six in each group, were injected intraperitoneally with one of the following agents. Groups 1, 2, and 3 (controls) received saline, RPMI and mouse immunoglobulin G (IgG), respectively. Groups 4 and 5 were injected with anti-I-E antibodies, 80 micrograms and 1000 micrograms, respectively. Similarly, groups 6 and 7 received anti-I-A, 100 micrograms and 750 micrograms, respectively. The treatments were repeated on days 1, 2, 5, 8, and 11 after S-antigen injection. All these animals were killed on day 18. In addition, two groups of rats sensitized with S-antigen were treated with 750 micrograms anti-I-A antibodies on days 5, 6, and 7 (group 8) and on days 7, 8 and 9 (group 9). An additional group (group 10) of Lewis rats was treated with 750 micrograms anti-I-A 1 day prior to and on days 1 and 2 after S-antigen injection. These group-10 animals were killed on day 31. Histopathologically, the enucleated globes of animals treated with high dose anti-I-A revealed marked suppression or inhibition of uveitis development. Such inhibition was virtually complete when the antibody was administered within a week of S-antigen injection, and the inhibitory effect lasted for at least 31 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunohistochemical localization of catalase in ocular tissue

Localization of catalase in rat and bovine ocular tissues was investigated by an immunohistochemical method. Antisera to purified catalase was raised in a rabbit. Purity of catalase was determined by gel electrophoresis and specificity of the antibody was tested by immunoblot. The immunohistochemical method revealed the presence of catalase predominantly in epithelial and endothelial structures of the eye and in the retina, except in the outer segments. Catalase was found in abundance in those structures that are frequently exposed to oxygen metabolites under physiologic conditions and in such pathologic states as intraocular inflammations. These findings thus suggest that catalase, along with other antioxidant enzymes, may offer protection against the damaging effects of hydrogen peroxide.