Modulation of macrophage suppressive activity and prostaglandin release by lymphokines and interferon: comparison of alveolar, pleural and peritoneal macrophages

In order to better characterize the mechanisms which regulate the immune response at the pulmonary level, the effects of beta-interferon (IFN-beta) and lymphokines (LK) on prostaglandin E (PGE) release and the suppressive capacity of mouse resident alveolar (AM phi) and pleural macrophages (PlM phi) were investigated in comparison with peritoneal macrophages (PM phi). After in vitro exposure to IFN-beta, PlM phi and PM phi showed a significant decrease of suppressive capacity and PGE release, whereas LK treatment did not affect such activities. In contrast, pre-treatment of AM phi with LK caused a strong impairment of their suppressive capacity. This effect was optimal after an incubation time of 20 h, was evident also at very low doses of LK and was not paralleled by any change of PGE release. Again in contrast with PlM phi and PM phi, suppressive capacity of AM phi was decreased only by very high doses of IFN-beta, whereas lower doses caused either an increase or no change of this activity. Furthermore, PGE release by AM phi was markedly increased after treatment with IFN-beta. Thus, suppressive capacity of AM phi appears to be controlled by different mechanisms from those of PlM phi and PM phi. In addition, a dissociation is evident between suppressive capacity and PGE release by AM phi.