IL-10 INHIBITS PROSTAGLANDIN E(2) PRODUCTION BY LIPOPOLYSACCHARIDE-STIMULATED MONOCYTES

Since IL-10 has recently been shown to exhibit pleiotropic effects on human monocytes, it was of interest to determine the effect of this cy tokine on prostaglandin E(2) (PGE(2)) production by monocytes. Recombi nant IL-10 (rIL-10) did not significantly affect PGE(2) production by lipopolysaccharide (LPS)-unstimulated monocytes, but efficiently inhib ited PGE(2) production by LPS-stimulated monocytes. The inhibition by rIL-10 was achieved in a dose-dependent manner. Recombinant IL-4 also inhibited PGE(2) production at the same degree as rIL-10. Viral IL-10 inhibited PGE(2) production by monocytes in a similar fashion as did h uman rIL-10. Endogenously produced IL-10 was also shown to inhibit PGE (2) production by LPS-stimulated monocytes. Kinetic studies showed tha t the inhibition by rIL-10 on PGE(2) production was observed at least 3 h after LPS stimulation. Taken together, these results indicate that IL-10 may play an important role in modulating immunological response s via down-regulation of PGE(2) production by monocytes.