Prostaglandins as regulators in cellular immunity.

Guinea-pig peritoneal macrophages have been shown to generate substantial concentrations of E-type prostaglandins during culture in vitro. Partially purified lymphokine preparations stimulate PGE production by macrophages. Exogenous PGE1 and PGE2 are potent inhibitors of lymphocyte activation and secretion of lymphokines causing lymphocyte mitogenesis and macrophage migration inhibition. Also indomethacin augments the secretion of these lymphokines in vitro. It is therefore suggested that production of PGE by macrophages provides a physiological mechanism for the regulation of lymphocyte activation in reactions of delayed hypersensitivity.