Interleukin-22 (IL-22) is protein that in humans is encoded by the IL22 gene.
Gene location Chromosome 12.
IL-22 is an α-helical cytokine.
IL-22 binds to a cell surface receptor composed of IL-10R2 and IL-22R1 subunits.
IL-22R is expressed on tissue cells, and it is absent on immune cells.
IL-22 is produced by several populations of immune cells at a site of inflammation.
Producers are αβ T cells classes Th1, Th22 and Th17 along with γδ T cells, NKT, ILC3, neutrophils and macrophages.
IL-22 effects non-hematopoietic cells – mainly stromal and epithelial cells.
IL-22 participates in both wound healing and in protection against microbes.
IL-22 dysregulation takes part in autoimmune diseases like systemic lupus erythematosus, rheumatoid arthritis and psoriasis.
IL-22 biological activity is initiated by binding to a cell-surface complex composed of receptor chains and is regulated by interactions with a soluble binding protein.
IL-22 receptor chains play a role in cellular targeting and signal transduction to initiate and regulate immune responses.
IL-22 contributes to immune disease through the stimulation of inflammatory responses.
It promotes hepatocyte survival in the liver and epithelial cells in the lung and gut similar to IL-10.
The pro-inflammatory versus tissue-protective functions of IL-22 are regulated by the often co-expressed cytokine IL-17A .
IL-22 cytokine targets are mostly non-hematopoietic cells.
IL-22 cytokine targets include
epithelial and stromal cells of liver, lung, skin, thymus, pancreas, kidney, gastrointestinal tract, synovial tissues, heart, breast, eye and adipose tissue.
IL-22 is a member of a group of cytokines called the IL-10 family, that includes IL-19, IL-20, IL-24, and IL-26:
a class of potent mediators of cellular inflammatory responses.
It shares use of IL-10R2 in cell signaling with other members of this family, IL-10, IL-26, IL-28A/B and IL-29.
IL-22 production is induced primarily through IL-23 receptor signalling.
IL-23 is produced by dendritic cells after recognition of ligands by specific Toll-like receptors.