HUMAN-LEUKOCYTE ANTIGEN - CLASS II-POSITIVE HUMAN CORNEAL EPITHELIAL-CELLS ACTIVATE ALLOGENEIC T-CELLS

Purpose. To achieve a better understanding of the mechanism of corneal immune diseases, including corneal allograft rejection, the authors e xamined the potential of human corneal epithelial (HCE) cells to activ ate allogeneic T lymphocytes. Methods. The mixed lymphocyte-HCE cell r eaction (MLCER) was performed as follows: HCE cells from primary cultu res, with or without treatment with interferon-gamma (IFN-gamma),were treated with mitomycin C and then mixed with peripheral blood lymphocy tes (PBL) from normal volunteers. Triplicate cultures were incubated f or 7 days. Interleukin-1-alpha (IL-1-alpha) was added to some cultures to examine its effect on MLCER. The lymphocyte responses were measure d by H-3-thymidine uptake for the last 18 hours of incubation in MLCER . Results. IFN-gamma-treated, HLA-class-II-bearing HCE cells stimulate d allogenic lymphocytes, whereas IFN-gamma nontreated, class-II-negati ve HCE cells did not. The stimulation by IFN-gamma-treated HCE cells w as blocked by anti-HLA class II monoclonal antibody. In addition, exog enous IL-1-alpha reduced the lymphocyte response in MLCER. This effort was inhibited by indomethacin. Conclusions. This study demonstrates t hat HLA-class-II-bearing HCE cells can activate allogeneic PBL by a ma jor histocompatibility complex class II-dependent mechanism. In additi on, HCE cells may regulate immune reactions, probably through prostagl andin production caused by IL-1.