CHARACTERIZATION OF MONOCLONAL-ANTIBODIES RECOGNIZING RETINAL-PIGMENTEPITHELIAL ANTIGENS

Purpose. To purify and characterize retinal pigment epithelial protein s exhibiting uveitogenic characteristics after immunization of Lewis r ats, a broad panel of monoclonal antibodies directed against retinal p igment epithelial (RPE) protein antigens, was isolated. Methods. Bovin e RPE detergent extracts were used to isolate monoclonal antibodies ag ainst RPE antigens. Species and tissue specificity within the eye was tested through immunocytochemical analysis. Western blot analysis was used to determine the molecular weight of the RPE antigens. Results. S everal RPE-reactive antibodies were obtained. At least four monoclonal antibodies were isolated that reacted with different RPE antigen type s. Against most of the antigens more than one hybridoma cell line was isolated. Two hybridoma lines were isolated producing antibodies, whic h on immunocytochemical analysis showed strong reactivity with the RPE and eye muscle tissue. The latter monoclonal antibody recognizes a 32 kD protein in RPE cells. Five monoclonal antibodies recognize a prote in with an apparent molecular weight of 65 kD. One cell line was isola ted that produced antibodies showing an irregular reaction pattern wit h both iris and ciliary body. Conclusions. RPE cells, striated eye mus cle and smooth muscle cells share a 32 kD antigenic protein. This anti gen is present in almost all ocular epithelial cells. Based on reactio n patterns on Western blot and immunocytochemical analysis, there are at least three different 65 kD RPE antigens, two of which are RPE-spec ific and one of which is also present in the kidney epithelium.