STIMULATION OF MACROPHAGES WITH IFN-GAMMA OR TNF-ALPHA SHUTS OFF THE SUPPRESSIVE EFFECT PLAYED BY PGE(2)

PGE(2) has been shown to be able to interfere with various lymphocyte and macrophage functions, but its effects on macrophage activation are still unclear. In this study, carried out on peritoneal macrophages o btained from healthy, tumour-bearing and Corynebacterium parvum-treate d mice, we demonstrated that PGE(2) is involved in the down-regulation of macrophage activation, but it cannot exert its inhibiting effect w hen macrophages are further stimulated with activating cytokines, such as IFN gamma and TNF alpha. Our findings provide new insight into how macrophage tumoricidal activity may be induced and maintained even in presence of significant levels of PGE(2).