Human lymphocytes induce a differential release of prostaglandin E2 and interleukin 1-like mononuclear cell factor from normal blood monocytes.

Lymphocytes influence the production of both prostaglandin E2 (PGE2) and interleukin 1 (IL 1) by monocytes. We have examined whether these two products are released concomitantly or not under identical culture conditions using monocyte- and lymphocyte-enriched populations obtained on Percoll gradient. IL 1 was measured as mononuclear cell factor (IL 1/MCF). When incubated with concanavalin A, the monocyte-enriched fraction (MF; 80-91% monocytes), but not the lymphocyte-enriched fraction (LF; 95% lymphocytes) produced increasing amounts of PGE2 and MCF. However, when LF cells were added to MF cells in culture, a 40% to 60% decrease of PGE2 secretion was observed whereas the MCF production remained unchanged or increased up to 26-fold. Such a dissociation between IL 1 and PGE2 production by monocytes indicates independent regulation mechanisms in controlling the immune response under the influence of lymphocytes.