The biochemical mechanisms of action of the interferons.

The interferon family of proteins consists of a variety of antigenically distinct types that are encoded by different genes. Several of these genes have been cloned and the availability of large amounts of the recombinant interferons has greatly facilitated characterization of their biochemical and biological activities. The specificity of interaction of interferons with cell surface receptors has been investigated in binding and covalent cross-linking experiments employing 125I-labeled interferons. In addition to their antiviral activity, the interferons have effects on cell growth and differentiation. The interferons also are potent modulators of the immune response. The interferons exert their biological activities by altering the expression of several cellular proteins. Current knowledge about the mechanisms of signal transduction and the regulation of expression of interferon-induced mRNAs and proteins are discussed.