The IFN-αfamily consists of 24 or more genes or pseudo-genes. IFN-α(II) is one of the two distinct families (I and II) of human IFN-α. The α interferons are mainly produced by lymphocytes, monocytes, macrophages, and cell lines such as Namalwa and KG1 following induction by viruses, nucleic acids, and glucocorticoid hormones. They are involved in virus resistance on target cells, inhibition of cell proliferation, induction of cytokines and regulation of expression of MHC class I antigens.