Description
Interleukin-28A (IL-28A), also known as IFN-λ2, is a cytokine distantly related to type I interferons and the IL-10 family. It exerts its biological effects through a receptor that also binds IL-28B and IL-29 (1). This receptor is a heterodimeric class II cytokine receptor that consists of IL-10RB and IL-28RA. IL-28A activities overlap those of type I IFNs and include anti-viral activity and up-regulation of MHC class I antigen expression (2). The expression of IL-28A is induced by virus infection or double-stranded RNA. Upon binding to the receptor, it also induces JAK kinase activation and phosphorylation of STAT and STAT2 (3). IL-28A represents a potential novel approach for therapy of Th1-mediated inflammatory diseases such as T cell-mediated hepatitis (4)