IFN-γ is structurally different from type I interferon and its major activity is immunoregulation. It has antiviral and antiparasitic activities, and inhibits activity of many normal and transformed cells. IFN-gamma works with TNF-alpha and TNF-beta to inhibit the proliferation of several types of cells. IFN-gamma has been implicated in the expression of class II histocompatibility antigens in cells that do not normally produce them, leading to autoimmune disease. rHu IFN-γ produced in E. coli is a single, non-glycosylated, polypeptide chain that contains 144 amino acids and has a molecular mass of 16.88 kDa.