Biological properties of virus-induced interferons.

Both mouse and human cells elaborate more than one molecular species of interferon. Mouse interferon consists of a number of polypeptides which all probably have antiviral activity. Human fibroblast interferon is a single polypeptide, but other human cells produce special species of interferons, which show different physical and biological properties. The human interferons certainly differ in their extent of glycosylation and hydrophobicity, and may have different amino-acid sequences, since it has recently been reported that when the messenger RNAs extracted from fibroblast and lymphoblastoid cells are translated in Xenopus oocytes, the products are antigenically distinguishable (26,29,40). If the polypeptide sequences are different, then there may be at least two structural genes for human interferon. Both the antiviral and anticellular activities of mouse and human interferon probably reside in the same molecule.