PLATELET-ACTIVATING-FACTOR MODULATES INTERLEUKIN-6 PRODUCTION BY MOUSE FIBROBLASTS

We compared the effects of platelet-activating factor (PAF), interleukin-1-beta (IL-1-beta) and polyriboinositic-polyribocytidylic acid (poly-I:C) on IL-6 production by confluent L929 mouse fibroblasts. At concentrations above 1-mu-M, PAF dose-dependently enhanced IL-6 production; at 5-mu-M PAF this increase (72.7 +/- 19.9 U/ml) was higher than that evoked by 100 U/ml IL-1-beta (5.7 +/- 0.4 U/ml) or 50-mu-g/ml poly-I:C (39.3 +/- 6.7 U/ml). The IL-6 production induced by 5-mu-M PAF was not inhibited by addition of the specific PAF antagonist BN 52021 (10-mu-M) to the incubation medium. These results demonstrate that, as this is the case for IL-1, PAF also modulates IL-6 production.