Interferons: Selectivity and Specificity of Action in Cell-Free Systems

Abstract
The inhibition by interferons of viral replication was studied with cell-free preparations of the enzyme RNA synthetase derived from calf kidney cells infected with influenza virus and from chick embryo fibroblasts infected with Newcastle disease virus. Calf, mouse, and chicken interferons inhibited these enzymes with the same characteristic species specificity observed in tissue culture. A mechanism of action is proposed.