Animal-free Recombinant Human IL-29 (IFN-lambda 1) is expressed in human 293 cells as a glycoprotein with an apparent molecular mass of 29 and 35 kDa. IL-29 has immunomodulatory activity and may function in antiviral immunity. This cytokine is produced in a serum-free, chemically defined media. Production in human 293 cells offers authentic human glycosylation which contributes to stability in cell growth media and other applications. The purity is greater than 95%.