Retinal S antigen chromatographically purified from whole retina, induces experimental autoimmune uveoretinitis in laboratory animals. The 48K protein, a soluble protein found in rod outer segments, is purified through its specific binding to photoexcited rhodopsin and is involved in the quenching of light-induced guanosine 3',5'-monophosphate-phosphodiesterase activity. Biochemical, immunological, functional, and pathological tests showed that retinal S antigen and the 48K protein are identical.

Hybridomas producing monoclonal antibodies to the retinal S antigen were obtained by fusion of spleen cells from a BALB/c mouse immunized with purified bovine S antigen and NS-1 myeloma cells. Six cloned hybridomas were selected and expanded as large scale cultures and as ascites in mice. The specificity of the antibodies produced by these hybridomas was assessed by ELISA and immunofluorescence. All were specific for S antigen, except one which showed slight reactivity with other proteins. One antibody was specific for bovine S antigen, whereas the others showed cross reactivity with purified S antigens from various mammals. Immunofluorescence allowed to demonstrate the presence of common epitopes of S antigen in the retinal photoreceptor cells of species representative of every class of Vertebrates.

No abstract