Functional Properties of Proteins Coded by Three Human α-Interferon Genes and a Pseudogene

We have characterized the functional properties of four highly purified recombinant human class I α-interferon subtypes whose biological activities have not been described previously. We selected biological and biochemical activities that may discriminate between different functions of these molecules. We found that the α subtypes could be discriminated only by antiviral-host range specificity and natural killer cell activation. Differences in their antiproliferative activity were cell line dependent. Competitive binding, antiproliferative activity in agar, enhancement of expression of HLA-ABC, elevation of 2′-5′-oligoadenylate synthetase levels and enhancement of phosphorylation of the M r 69,000 protein kinase did not allow discrimination among the αI subtypes on the tested cell lines.