Interferon and Prostaglandins: Effects on Human Natural and

(PGE) were evaluated on subpopulations of human peripheral blood mononuclear lymphocytes (PBl) that mediate natural killer (NK) activ-ity, antibody-dependent cell-mediated cytotoxicity (ADCC), or lectin-induced cellular cytotoxicity (L1CC). When PBl were separated into subpopulations depending on the presence or absence of receptors for sheep erythrocytes (E+ or E-, respectively) or for the Fcy receptor (FcyR+ or FcyR-, respectively), L1CC was mainly associated with the E+FcyR- cells and to a considerably lesser extent with E+FcyR+ cells. In contrast, NK activity and ADCC were associated with the E+ and E-subpopulations that had FcyR. IFN treatment had stronger effects on the FcyR+ subpopulations. Boosting of L1CC occurred maximally in the E+FcyR+ subpopulation, and the activity of the E+FcyR- cells in-creased only modestly. IFN had a greater augmenting effect on the NK activity and ADCC of E+FcyR+ cells than on E-FcyR+ cells. PGE strongly inhibited all three types of cell-mediated cytotoxicity and wa