Effect of prostaglandins on complement production by tissue macrophages.

Tissue macrophages produce several proteins of the complement system. The mechanisms that regulate this process are poorly understood. The established ability of certain prostaglandins to influence macrophage secretory activity suggests that these lipid mediators may also modulate complement production (CP). Using the guinea pig peritoneal macrophages, we determined the effects of selected prostaglandins on in vitro CP and found that PGE2 inhibited production of complement proteins but not lysozyme; the response of elicited and resident peritoneal cells to PGE2 was identical; and PGE1, PGF2 alpha, and PGI2 had no detectable effect. PGE2 may contribute to regulation of CP in vivo.