interferon

interferon , 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 .

interferon (IFN) Any of a number of proteins (see cytokine) that increase the resistance of a cell to attack by viruses by unmasking genes that synthesize antiviral proteins. In humans, three groups of interferons have been discovered: α-interferons from white blood cells; β-interferons from connective tissue fibroblasts; and γ-interferons from lymphocytes (see interleukin). Interferons are also produced by lymphocyte killer cells, which attack altered tissue cells, such as cancer cells. This converts other normal lymphocytes to killer cells and effects other changes in the immune system. Interferons produced using genetically engineered bacteria are used for treating some forms of hepatitis, some cancers, and multiple sclerosis.

interferon (inter-feer-on) n. a substance that is produced by cells infected with a virus and has the ability to inhibit viral growth. Particular interferons are effective only in the species that produces them. Preparations of human interferon produced by genetic engineering are used clinically in treating hepatitis B and certain lymphomas and other cancers (i. alfa), hepatitis C (i. alfa and peginterferon alfa), and multiple sclerosis (i. beta).