IL-10 inhibits cytokine production by activated macrophages.

DF Fiorentino, A Zlotnik, TR Mosmann… - … (Baltimore, Md.: 1950 …, 1991 - journals.aai.org
DF Fiorentino, A Zlotnik, TR Mosmann, M Howard, A O'Garra
Journal of immunology (Baltimore, Md.: 1950), 1991journals.aai.org
IL-10 inhibits the ability of macrophage but not B cell APC to stimulate cytokine synthesis by
Th1 T cell clones. In this study we have examined the direct effects of IL-10 on both
macrophage cell lines and normal peritoneal macrophages. LPS (or LPS and IFN-gamma)-
induced production of IL-1, IL-6, and TNF-alpha proteins was significantly inhibited by IL-10
in two macrophage cell lines. Furthermore, IL-10 appears to be a more potent inhibitor of
monokine synthesis than IL-4 when added at similar concentrations. LPS or LPS-and IFN …
Abstract
IL-10 inhibits the ability of macrophage but not B cell APC to stimulate cytokine synthesis by Th1 T cell clones. In this study we have examined the direct effects of IL-10 on both macrophage cell lines and normal peritoneal macrophages. LPS (or LPS and IFN-gamma)-induced production of IL-1, IL-6, and TNF-alpha proteins was significantly inhibited by IL-10 in two macrophage cell lines. Furthermore, IL-10 appears to be a more potent inhibitor of monokine synthesis than IL-4 when added at similar concentrations. LPS or LPS- and IFN-gamma-induced expression of IL-1 alpha, IL-6, or TNF-alpha mRNA was also inhibited by IL-10 as shown by semiquantitative polymerase chain reaction or Northern blot analysis. Inhibition of LPS-induced IL-6 secretion by IL-10 was less marked in FACS-purified peritoneal macrophages than in the macrophage cell lines. However, IL-6 production by peritoneal macrophages was enhanced by addition of anti-IL-10 antibodies, implying the presence in these cultures of endogenous IL-10, which results in an intrinsic reduction of monokine synthesis after LPS activation. Consistent with this proposal, LPS-stimulated peritoneal macrophages were shown to directly produce IL-10 detectable by ELISA. Furthermore, IFN-gamma was found to enhance IL-6 production by LPS-stimulated peritoneal macrophages, and this could be explained by its suppression of IL-10 production by this same population of cells. In addition to its effects on monokine synthesis, IL-10 also induces a significant change in morphology in IFN-gamma-stimulated peritoneal macrophages. The potent action of IL-10 on the macrophage, particularly at the level of monokine production, supports an important role for this cytokine not only in the regulation of T cell responses but also in acute inflammatory responses.
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