Interleukin 22 binding protein (IL-22BP), also known as CRF2-10, CRF2-X, and IL-22RA2, is a 35-45 kDa secreted glycoprotein in the type II cytokine receptor family (CRF). IL-22BP specifically binds to and inhibits interleukin 22 activity by blocking the interaction of interleukin 22 with its cell surface receptor.IL-22BP is produced by dendritic cells (DC), epithelial cells, activated B cells, and activated monocytes. It is constitutively expressed by DC but is down-regulated during local inflammation and in response to tissue damage. IL-22BP is critical for limiting IL-22 induced epithelial cell proliferation during wound healing, and its deficiency can enable uncontrolled proliferation and enhance tumor development.