interferon(redirected from alpha-interferon)
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interferon (ĭnˌtərfērˈŏn), any of a group of proteins produced by cells in the body in response to an attack by a virus. A cell infected by a virus releases minute amounts of interferons, which attach themselves to neighboring cells, prompting them to start producing their own protective antiviral enzymes. The result is impairment of the growth and replication of the attacking virus. Interferon has also been shown to have some antitumor properties. There are three known classes of interferons: alpha-, beta-, and gamma-interferons.
Although they were discovered in the 1950s, the medical use of interferons was impractical until the recombinant DNA techniques of genetic engineering made it possible to mass produce them. Interferons used as drugs include alpha-interferon, for hepatitis B and C, human papillomavirus, hairy-cell leukemia, and Kaposi's sarcoma (a cancer associated with AIDS), and beta-interferon, for multiple sclerosis.
See also immunity.
a protective protein manufactured by cells in mammals and birds and by cell cultures in response to their infection by viruses, suppressing the reproduction (replication) of the viruses in the cells.
Interferon was discovered in 1957 in the cells of infected chickens by the English scientists A. Isaacs and J. Lindenman. It was later discovered that the formation of interferon is also induced by bacteria, rickettsia, toxins, nucleic acids, and synthetic polynucleotides. Interferon is not an individual substance but a group of proteins of low molecular weight (25,000110,000). They are stable within a wide pH range, resistant to nucleases, and destroyed by proteolytic enzymes. The formation of interferon in the cells is due to the development of a virus in them—that is, it is a reaction of the cells to the penetration of foreign nucleic acid. Interferon is not found after the disappearance of the infecting virus from the cells or in normal cells. The mechanism of interferon’s action is different in principle from that of antibodies: it is not specific in relation to viral infections (it is active against a variety of viruses), and it does not neutralize the infectiousness of the virus, but suppresses the reproduction of the virus in the body by inhibiting the synthesis of the viral nucleic acids. Interferon is ineffective when it enters cells after a viral infection has already developed in them. Moreover, interferon is, as a rule, specific for the cells that form it; for example, the interferon of chicken cells is active in those cells only and does not inhibit the reproduction of a virus in rabbit or human cells. It has been suggested that it is not interferon itself that acts on the viruses, but rather another protein that is produced under its influence. Encouraging results have been obtained in testing interferon for the prevention and treatment of viral diseases (herpes infection of the eyes, influenza, cytomegaly). However, broad clinical use of interferon is limited by the difficulty of obtaining the preparation, the necessity for multiple injections, and its species specificity.
REFERENCESSolov’ev, V. D., and T. A. Bektimirov. Interferon v teorii i praktike meditsiny. Moscow, 1970.
Isaacs, A., and J. Lindenmann. “Virus Interference. I: The Interferon.” Proceedings of the Royal Society of London, series B:Biological Sciences, 1957, vol. 147, no. 927.
Vilček, I. Interferon. Vienna-New York, 1969.
KH. KH. PLANEL’ES