Interferon-alpha: a gene family in therapeutic use

Several variants of interferon-alpha (IFN-alpha) were isolated and purified to homogeneity. They differed to various degrees in biological properties. However, three IFN-alpha 2 variants showed only minor differences from a variant called IFN-alpha 88 with regard to their ability to inhibit growth and to bind to specific receptors, tested on Daudi cells. Two monoclonal antibodies were studied, which showed overlapping specificity for at least one peptide obtained after HPLC separation of tryptic digests. The monoclonal antibodies could discriminate between sequence differences to a much higher degree than the receptor on Daudi cells. It is concluded that the receptor is degenerate and binds well to different structural variants of IFN and that for therapeutic use, several of the variants will probably have the same biological potency.