caution:It is uncertain whether Met-1 or Met-5 is the initiator.,function:Cytokine with immunomodulatory activity. Up-regulates MHC class I antigen expression. Displays potent antiviral activity. Also displays antitumor activity. Ligand for the heterodimeric class II cytokine receptor composed of IL10RB and IL28RA. The ligand/receptor complex seems to signal through the Jak-STAT pathway.,induction:By viral infections or double stranded RNA.,similarity:Belongs to the IL-28/IL-29 family.,