Interleukine 10 (IL-10) is a cytokine produced primarily by monocytes and to a lesser extent by
lymphocytes. This cytokine has pleiotropic effects in immunoregulation and inflammation. It down-
regulates the expression of Th1 cytokines, MHC class II Ags, and costimulatory molecules on
macrophages. It also enhances B cell survival, proliferation, and antibody production. This
cytokine can block NF-kappa B activity, and is involved in the regulation of the JAK-STAT signaling
pathway. Knockout studies in mice suggested the function of this cytokine as an essential immunoregulator in the intestinal tract.