Interleukin-22(IL-22) belongs to a group of cytokines called the IL-10 family or IL-10 superfamily (including IL-19, IL-20, IL-24, and IL-26) which are a class of potent mediators of cellular inflammatory responses. It shares use of IL-10R2 in cell signaling with other members of this family, such as IL-10, IL-26, IL-28A/B and IL-29. IL-22 is produced by activated DC and T cells and initiates innate immune responses against bacterial pathogens in epithelial cells such as those in the lung and gut. IL-22 along with IL-17 is produced by splenic LTi-like cells and Th17 cells and likely plays a role in the coordinated response of both adaptive and innate immune systems.IL-22 signals through a receptor system consisting of IL-10R-β/CRF2-4 and IL-22R, both of which are members of the class II cytokine-receptor family.

> 98% as determined by SDS-PAGE