The Interferons: 50 Years after Their Discovery, There Is Much More to Learn

The interferons (IFNs) and their receptors represent a subset of the class 2 alpha-helical cytokines that have been in chordates for millions of years. This brief review focuses on the discovery and purification of interferons, cloning of human IFN-alpha and IFN-beta, interferon receptors, activities and therapeutic uses of interferons, and the side effects of interferons.