The Breadth of Interferon Action

For more than a decade since its discovery in 1957, interferon has been regarded exclusively as an antiviral substance, inhibiting both cytopathic and oncogenic ribonucleic acid and deoxyribonucleic acid viruses. During the past years it has become increasingly clear that interferon action also encompasses various nonantiviral activities. This chapter discusses the breadth of interferon action are hampered by the fact that pure interferon is unavailable. Thus, the experiments have been done with crude or partially purified, but still impure, interferon preparations. There are other interferon effects which may be related to the observed efficacy of interferon in the treatment of animals inoculated with viral or nonviral agents, chemical carcinogens, or transplantable tumor cells; and these include the enhancement of the specific cytotoxicity of lymphocytes for target cells. Circumstantial evidence was provided that the phagocytosis-enhancing principle was actually interferon and not one or another impurity present in the interferon preparation.