IL-25 Recombinant Protein. Interleukin 25 (IL-25) is a member of the IL-17 family and is identified as a proinflammatory cytokine which is produced by Th17 effector cells thus enabling the Th17 subset to initiate or maintain the autoimmune process in diseases such as Rheumatoid Arthritis. IL-25 also induces activation of NF-kappa-B and stimulates production of the proinflammatory chemokine IL-8. IL-25 itself is activated through IL-23, IL-5, and TGF-beta.