Objective To investigate production of interleukine 6 (IL-6)and interleukine 8 (IL-8)by retinal pigment epithelial (RPE)cells and its inhibition by interleukine 1 receptor antigonist (IL-1ra).Methods cultured human RPE cells was treated with interleukine 1beta;(IL-1beta;,10ng/ml)and/orIL-1ra(IL-1ra,1、10、100 ng/ml).IL-6 and IL-8 mRNA and protein expression were detected by ELISA, immunohistochemistry and in situ hybridization (ISH)assay. Results IL-6 and IL-8 in conditioned media of RPE cells in controls was 2000 pg/ml and 5000 pg/ml respectively after stimulation of IL-1beta; FOR 8h.IL-1ra(100ng/ml)significantly inhibited IL-6(300 pg/ml,t=8.011,P＜0.01)and IL-8(450 pg/ml,t=11.446,P＜0.01) production compared with the controls.In situ hybridization displayed that there was a marked reduction in mRNA expression of IL-6 and IL-8 in IL-1ra treated group compared with controls.Conclusion The production of IL-6 and IL-8 can be significantly reduced by IL-1ra in cultured human RPE cells after stimulation of IL-1beta;
Objective To examine the influence of retinal pigment epithelium(RPE) cells on antigen-specific activatedlymphocytes in vitro,and to explore the role of RPE cells in the immune privilege of the eye. Methods Co-culture systems of RPE cells with antigen-specific T lymphocyte lines and resting T lymphocytes were established in vitro．Induction of apoptosis was detected by genomic DNA electrophoresis,DNA in situ end-labelling and flow cytometry. Results RPE cells induced apoptosis in antigen-specific activated T lymphocytes. 24 hours after culture,the signs of apoptosis appeared in lymphocytes co-incubated with RPE cells．As time of co-culture went on,the number of apoptosic cells increased．Quantitative analysis of apoptosic cells showed that apoptosic cells accounted for 5.95% after 24 hours, 9.38% after 48 hours,and 17.95% after 72 hours．In contrast,RPE cells induced few apoptosis in resting T lymphocytes. Conclusions These results suggest that RPE cells possess the ability to induce the apoptosis of invading lymphocytes. This phenomenon serves as a restrain mechanism of immune response and may be of vital importance in the maintenance of immune privilege in posterior segment of eye and in the protection of eye from the damage of immunogenic inflammation. (Chin J Ocul Fundus Dis, 1999, 15: 241-244)