Interleukin 22 (IL-22) is a class 2 α-helical cytokine that signals through the class 2 cytokine receptor and activates the JAK/STAT pathway. IL-22 is secreted by Th1, Th2, Tc22, and γδ T cells, dendritic, mast and NK cells. It stimulates expression of antimicrobial peptides from epithelial cells, thus hindering bacterial infections. Depending on the interactions with other cytokines, IL-22 can either promote inflammation or prevent tissue destruction by regulating host defense and tissue homeostasis at barrier surfaces.
