Interferon: a changing picture.

Concepts regarding the nature and function of interferon have undergone considerable modification since its initial description in 1957. A low-molecular-weight protein, interferon has been produced by a variety of host cells following exposure not only to most viruses but also to bacterial cells and endotoxins, rickettsiae, nucleotides and a polyanionic polysaccharide (Statolon). Interferon production and activity require de novo synthesis of cellular RNA and protein, although interferon induced in vivo by endotoxins appears to involve release from a preformed state.The pathogenesis of primary viral infections may be determined largely by non-immune defence mechanisms. Interferon, detectable in the host's serum and associated with leukocytes during the course of viral illness, may make an important contribution to recovery. Low toxicity, weak antigenicity and wide range of antiviral activity make interferon an attractive therapeutic possibility. Stimulation of inherent interferon-producing mechanisms by administration of relatively innocuous agents may prove beneficial in humans.