Interleukin 17E (IL-17E), also known as IL-25, is a member of the IL-17 family and is secreted and produced by type 2 helper T cells (Th2) and mast cells. It is similar in sequence to IL-17 and induces NF-κB activation and stimulates IL-8 production.IL-17E and IL-17B are ligands for the cytokine receptor IL-17RB. Studies in mice suggest that IL-17E may be a pro-inflammatory cytokine that facilitates the Th2-type immune response.IL-17E induces the production of other cytokines in a variety of tissues, including IL-4, IL-5, and IL-13, which stimulates eosinophilia. This cytokine is an important molecule in the regulation of intestinal immunity and is involved in chronic inflammation associated with the gastrointestinal tract.IL-17E kills certain types of breast cancer cells.