IL-25 is a cytokine that shares the sequence similarity with IL17. This cytokine can induce NF-κB activation, and stimulate the production of IL8. Both this cytokine and IL17B are ligands for the cytokine receptor IL17RB. Studies of the similar gene in mice suggested that this cytokine may be a proinflammatory cytokine favoring Th2-type immune response. Two alternatively spliced transcript variants of this gene encoding distinct isoforms have been reported. IL-25 is a cytokine that belongs to the IL-17 cytokine family and is secreted by type 2 helper T cells (Th2) and mast cells. It is also known as IL-17E.