Interleukin-10 (IL-10) is a cytokine with anti-inflammatory properties, produced by various immune cells including monocytes, macrophages, and T cells. IL-10 acts through a transmembrane receptor complex composed of IL-10R1 and IL-10R2, regulating immune cell functions. In monocytes and macrophages, IL-10 reduces the production of inflammatory mediators, inhibits antigen presentation, and enhances phagocytosis. It also plays a role in B cell and T cell biology, contributing to induced tolerance and limiting over-whelming immune reactions. The biological relevance of IL-10 is evident in both IL-10-deficient and over-expressing animals, where it helps maintain gut homeostasis and tolerance to commensal bacteria. IL-10 is involved in immune-mediated diseases, such as chronic inflammatory bowel diseases, psoriasis, and rheumatoid arthritis, and its activity can be modulated for therapeutic purposes.Interleukin-10 (IL-10) is a cytokine with anti-inflammatory properties, produced by various immune cells including monocytes, macrophages, and T cells. IL-10 acts through a transmembrane receptor complex composed of IL-10R1 and IL-10R2, regulating immune cell functions. In monocytes and macrophages, IL-10 reduces the production of inflammatory mediators, inhibits antigen presentation, and enhances phagocytosis. It also plays a role in B cell and T cell biology, contributing to induced tolerance and limiting over-whelming immune reactions. The biological relevance of IL-10 is evident in both IL-10-deficient and over-expressing animals, where it helps maintain gut homeostasis and tolerance to commensal bacteria. IL-10 is involved in immune-mediated diseases, such as chronic inflammatory bowel diseases, psoriasis, and rheumatoid arthritis, and its activity can be modulated for therapeutic purposes.