Interleukin 29 (IL-29), also known as IFNlambda 1, is a type III interferon produced by virally infected cells. It is thought to play an important role in host defenses against multiple microbes and shares homology with IL-28. Recombinant IL-29 is a non-glycosylated Protein, containing 179 amino acids, with a molecular weight of 19.9 kDa