IL-10

Interleukin-10 (IL-10) is the founding member of an anti-inflammatory cytokine family that includes IL-19, IL-20, IL-22, IL-24 and IL-26. This 18.5 kDa homodimeric cytokine is produced by nearly all immune cells, with regulatory T cells, Th1 cells, macrophages, dendritic cells and B cells being major sources. IL-10 engages a heterodimeric receptor (IL-10Rα/CD210 and IL-10Rβ) and signals through JAK1/TYK2-STAT3 to suppress pro-inflammatory cytokine (TNF, IL-1, IL-6, IL-12) production, downregulate MHC-II and co-stimulatory molecules on antigen-presenting cells, and inhibit macrophage and T-cell effector functions. This feedback restraint prevents immunopathology during infection, but is co-opted by tumors to achieve immune evasion; IL-10 pathway polymorphisms confer risk of inflammatory bowel disease and autoimmunity.