Effect of a Murine Beta-Interferon Preparation on Phagocytosis and Cyclic AMP Levels in Mouse Peritoneal Macrophages

Mouse peritoneal macrophages (MPM) cultivated with a mouse beta-interferon preparation (MuIFN-β or "mock" IFN were tested for phagocytic ability and intracellular levels of adenosine 3′,5′-cyclic monophosphate (cAMP). Suspensions of nonopsonized Escherichia coli (E. coli) were used for phagocytosis experiments. Treatment of MPM with 10¹–10³ U per ml of MuIFN-β stimulated the phagocytic activity and raised the levels of cAMP in MPM. The effect of MuIFN-β on cAMP levels were dose and time dependent. Maximal cAMP levels were seen when MPM were incubated with 10³–10⁴ U per ml of MuIFN-β for five hours. Simultaneous addition of MuIFN-β and the adenylcyclase inhibitor N-etylmaleimide to the MPM cultures prevented the rise in cAMP levels but not the increased phagocytic capacity. MuIFN-β induced enhancement of phagocytosis and elevation of cAMP levels in MPM seem to be two parallel but not interlinked processes.