MHC CLASS-II POSITIVE RETINAL-PIGMENT EPITHELIAL (RPE) CELLS CAN FUNCTION AS ANTIGEN-PRESENTING CELLS FOR MICROBIAL SUPERANTIGEN

Retinal pigment epithelial (RPE) cells induced to express MHC class II (HLA-DR) by incubation with interferon gamma (IFN-gamma) were investi gated for their ability to present a microbial superantigen to T lymph ocytes. Superantigens bind to MHC class II antigens and appear to play a role in a number of infectious and autoimmune diseases through stim ulation of large numbers of T cells. Primary cultures of human RPE cel ls treated with IFN-gamma for three days to induce HLA-DR expression b ound staphylococcal enterotoxin E (SEE) via HLA-DR and presented SEE t o T cells as measured by proliferation of purified peripheral blood T cells and IL-2 synthesis by the Jurkat T cell line. Untreated RPE cell s were essentially ineffective as superantigen presenting cells. These results suggest that MHC class II expressing RPE cells could contribu te to immune and inflammatory activity in the eye by presenting supera ntigens to T lymphocytes.