IL-10 induces IL-10 in primary human monocyte-derived macrophages via the transcription factor Stat3.

IL-10 is an important immunosuppressive cytokine that can down-regulate expression of other cytokines and has been shown to down-regulate itself. We show, in this study, that treatment of human monocyte-derived macrophages with IL-10 induces IL-10 mRNA in a dose- and time-dependent manner with an optimum induction at 100 ng/ml and at 6 h, whereas IL-10-induced IL-10 protein can be detected at 18 h. In the same cells, IL-10 can partially suppress IL-10 mRNA induced by LPS, but only down to the level of IL-10-induced IL-10.