IFNL3, also known as Interferon lambda-3, is a secreted protein which belongs to the IL-28/IL-29 family. It is a cytokine with immunomodulatory activity. It up-regulates MHC class I antigen expression. This protein displays potent antiviral activity and antitumor activity. It seems to signal through the Jak-STAT pathway. It also contributes to viral resistance and is known to be upregulated by interferons and by RNA virus infection. Recombinant human IFNL3, fused to His-tag at C-terminus, was expressed in insect cell and purified by using conventional chromatography techniques.