1222 Ligation of CD59 expressed by normal RPE cells induces activation of T-lymphocytes via CD2 signal transduction pathways and cytokine mRNA expression in RPE cells

Purpose TO examine the ability of retinal pigment epithelial (RPE) cells to superantigen to T lymphoc e&t2 resent bacterial es. Methods RPE cells, er interferon gamma (INFg) treated or untreated, were coincubated with Jurkat T-cells, staphylococcal enterotoxin E (SEE), and PMA for 24 hours. Supernatants were collected for interleukin-2 (IL-2) assay. Raji B-calls were assayed for comparison. Binding of SEE to RPE cells was determined with biotinylated SEE which was detected with phycoerythin-conjugated streptavidin and bv flow cvtometry. Results On a per cell basis, INFG activated RPE cells induced an IL-2 release that was about l/20 of that amount stimulated by Raji cells. The antiaen presentina capacitv of RPE cells increased with-the-density of HLA-DR-epitops per cell. SEE bound only to HLA-DR positive, INFg treated RPE cells. Binding of SEE to RPE cells as well as the release of IL-2 was abolished bv antibodies to HLA-DR. HLA-DR negative RPE celis did not stimulate IL-2 release. Conclusions Only INFg activated RPE cells presented superantigens. Thus, RPE cells exposed to INFg have the capacity to bind and present bacterial superantigen to T cells and, both, may play a role in ocular inflammatory processes.