IFN-omega is a type I interferon that can be induced by virus-infected leukocytes. Members of the type I interferon family, which includes IFN-alpha, IFN-beta, and IFN-omega, signal through the IFNAR-1/IFNAR-2 receptor complex, and exert antiviral and antiproliferative activities. IFN-omega exhibits about 75% sequence homology with IFN-alpha, and contains two conserved disulfide bonds that are necessary for full biological activity. Recombinant Human IFN-omega is a 19.9 kDa protein consisting of 172 amino acid residues.