Polypeptide induction by recombinant human IFN-gamma.

Partially purified natural human IFN-gamma has been shown to induce the synthesis of a set of unique polypeptides that are not induced by comparable amounts of IFN-alpha and IFN-beta. In addition, a set of polypeptides is induced in common by all three IFNs. The present study utilized a pure recombinant IFN-gamma and a monoclonal antibody against IFN-gamma to investigate whether the unique polypeptide-inducing properties previously reported are due to IFN-gamma itself. With the possible exception of two polypeptides, the results demonstrate conclusively that IFN-gamma is the sole molecular species responsible for the induction of all polypeptides, including those whose induction pattern is unique to IFN-gamma. Very high doses of IFN-alpha and IFN-beta induce some of the latter set of polypeptides to a limited extent. Thus the differential effects of IFN-gamma compared to IFN-alpha and IFN-beta are, in part, quantitative rather than qualitative in nature.