INTERLEUKIN-1 REGULATES THE PROLIFERATION OF LEUKOCYTES IN HUMAN CORNEAL CELL-PERIPHERAL BLOOD LEUKOCYTE COCULTURES

We have documented the inability of human corneal epithelial-like cell s to suppress proliferation of peripheral blood leukocytes (PBLs) indu ced by allogeneic PBLs in a mixed leukocyte reaction (MLR). Instead, e nhanced proliferation of PBLs, albeit small, was consistently noted as indicated by uptake of radiolabeled thymidine. Maximum proliferation of PBLs was detected when a mixed leukocyte reaction (MLR) was conduct ed in the presence of corneal cells. High levels of interleukin-1 beta (IL-1 beta) were found during MLR irrespective of the presence of cor neal cells. High levels of IL-1 beta correlated well with observed syn ergistic stimulation of PBL proliferation by corneal cells and stimula ting allogeneic PBLs. In PBG-corneal cell cocultures, PBLs produced IL -1 beta; corneal cells contributed large amounts of prostaglandin E(2) (PGE(2)). Although indomethacin completely blocked prostaglandin E(2) production, it did not significantly alter the results. Our data show that PBLs and corneal cells can reciprocate each other's presence, an d, under appropriate conditions, corneal cells can deliver at least on e signal to enhance rather than suppress antigen-driven PBL proliferat ion. Our data suggest a role for immunoregulatory cytokines and prosta noids such as IL-1 beta and PGE(2) in these interactions.