Interleukin22

Interleukin-22, often abbreviated as IL-22, is a cytokine belonging to the IL-10 superfamily. It is a secreted protein primarily produced by immune cells, including T helper 17 (Th17) cells, Th22 cells, innate lymphoid cells (ILCs), and some dendritic cells. IL-22 plays a crucial role in the defense against extracellular pathogens, particularly bacteria and fungi, and in the maintenance of tissue homeostasis, especially in epithelial barriers like the skin, gut, and lungs.

The receptor for IL-22 is a heterodimer composed of the IL-22 receptor 1 (IL-22RA1) and the IL-10 receptor 2 (IL-10R2) subunits. These receptors are predominantly expressed on non-hematopoietic cells, such as epithelial cells, hepatocytes, and keratinocytes. Upon binding of IL-22 to its receptor complex, downstream signaling pathways are activated, leading to a variety of cellular responses.

These responses include the induction of antimicrobial peptides, enhanced epithelial cell proliferation and survival, and the promotion of tissue repair. In the context of inflammation, IL-22 can contribute to both protective and pathogenic mechanisms, depending on the specific tissue and the overall immune environment. Its involvement in inflammatory diseases like psoriasis and inflammatory bowel disease is an area of ongoing research. IL-22 is considered a key mediator in the interface between the immune system and barrier tissues.