interferon

(ĭn'tərfēr`ŏn), any of a group of proteins produced by cells in the body in response to an attack by a virusvirus,
parasite with a noncellular structure composed mainly of nucleic acid within a protein coat. Most viruses are too small (100–2,000 Angstrom units) to be seen with the light microscope and thus must be studied by electron microscopes.
..... Click the link for more information. . 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 engineeringgenetic engineering,
the use of various methods to manipulate the DNA (genetic material) of cells to change hereditary traits or produce biological products. The techniques include the use of hybridomas (hybrids of rapidly multiplying cancer cells and of cells that make a
..... Click the link for more information. made it possible to mass produce them. Interferons used as drugs include alpha-interferon, for hepatitishepatitis
, inflammation of the liver. There are many types of hepatitis. Causes include viruses, toxic chemicals, alcohol consumption, parasites and bacteria, and certain drugs.
..... Click the link for more information. B and C, human papillomavirushuman papillomavirus
(HPV), any of a family of more than 100 viruses that cause various growths, including plantar warts and genital warts, a sexually transmitted disease. Genital warts, sometimes called condylomata acuminata, are soft and often occur in clusters.
..... Click the link for more information. , hairy-cell leukemialeukemia
, cancerous disorder of the blood-forming tissues (bone marrow, lymphatics, liver, spleen) characterized by excessive production of immature or mature leukocytes (white blood cells; see blood) and consequently a crowding-out of red blood cells and platelets.
..... Click the link for more information. , and Kaposi's sarcomaKaposi's sarcoma
, a usually fatal cancer that was considered rare until its appearance in AIDS patients. First described by an Austro-Hungarian physician, Moritz Kaposi, in 1872, it appears in three forms and is characterized by vascular skin tumors.
..... Click the link for more information. (a cancer associated with AIDSAIDS
or acquired immunodeficiency syndrome,
fatal disease caused by a rapidly mutating retrovirus that attacks the immune system and leaves the victim vulnerable to infections, malignancies, and neurological disorders. It was first recognized as a disease in 1981.
..... Click the link for more information. ), and beta-interferon, for multiple sclerosismultiple sclerosis
(MS), chronic, slowly progressive autoimmune disease in which the body's immune system attacks the protective myelin sheaths that surround the nerve cells of the brain and spinal cord (a process called demyelination), resulting in damaged areas that are unable
..... Click the link for more information. .

See also immunityimmunity,
ability of an organism to resist disease by identifying and destroying foreign substances or organisms. Although all animals have some immune capabilities, little is known about nonmammalian immunity.
..... Click the link for more information. .

Interferon

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.

REFERENCES

Solov’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

interferon

[‚in·tər′fir‚än] (biochemistry) A protein produced by intact animal cells when infected with viruses; acts to inhibit viral reproduction and to induce resistance in host cells.

interferon

Biochem any of a family of proteins made by cells in response to virus infection that prevent the growth of the virus. Some interferons can prevent cell growth and have been tested for use in cancer therapy

interferon

[in″ter-fēr´on] any of a family of glycoprotein modifiers" >biological response modifiers used as antineoplastic agents and immunoregulators; they inhibit cellular growth, alter the state of cellular differentiation, have effects on the cell cycle, interfere with oncogene expression, alter cell surface antigen expression, have effects on antibody production, and regulate cytotoxic effector cells.interferon-α the major interferon produced by virus-induced leukocyte cultures; its primary producer cells are null cells, and its major activities are antiviral activity and activation of NK cells.interferon alfa-2a a synthetic form of interferon-α produced by recombinant technology that acts as a biologic response modifier, used as an antineoplastic in the treatment of hairy cell leukemia and AIDS-related Kaposi's sarcoma; administered intramuscularly or subcutaneously.interferon alfa-2b a synthetic form of interferon-α produced by recombinant technology that acts as a biologic response modifier, used in the treatment of veneral warts, hepatitis B, and chronic hepatitis C and as an antineoplastic in the treatment of hairy cell leukemia, malignant melanoma, non-Hodgkin's lymphomas, multiple myeloma, mycosis fungoides, and AIDS-related Kaposi's sarcoma; administered intramuscularly, subcutaneously, or intralesionally.interferon alfacon-1 a synthetic interferon related to both α and β interferons, produced by recombinant DNA technology; used in the treatment of chronic hepatitis C virus infection, administered subcutaneously.interferon alfa-n3 a highly purified mixture of natural human interferon proteins that acts as a biologic response modifier; used in the treatment of venereal warts, administered intralesionally.interferon-β the major interferon produced by double-stranded RNA-induced fibroblast cultures; the major producer cells are fibroblasts, epithelial cells, and macrophages, and its major activity is antiviral.interferon beta-1a a synthetic form of interferon-β produced by recombinant DNA techniques that acts as a biologic response modifier; used in the treatment of relapsing forms of multiple sclerosis; administered intramuscularly.interferon beta-1b a synthetic modified form of interferon-β produced by recombinant DNA techniques; used as a biologic response modifier in the treatment of relapsing forms of multiple sclerosis; administered subcutaneously.interferon-γ the major interferon produced by lymphocyte cultures that have been immunologically stimulated by mitogens or antigens; the major producer cells are lymphocytes" >T lymphocytes, and its major activity is immunoregulation.interferon gamma-1b a synthetic form of interferon-γ produced by recombinant technology that acts as a biologic response modifier and antineoplastic. It is used to reduce the frequency and severity of serious infections associated with chronic granulomatous disease, administered subcutaneously.

in·ter·fer·on (IFN),

(in'tĕr-fēr'on), A class of small (15-28 kD) protein and glycoprotein cytokines (15-28 kD) produced by T cells, fibroblasts, and other cells in response to viral infection and other biologic and synthetic stimuli. IFNs bind to specific receptors on cell membranes. Their effects include inducing enzymes, suppressing cell proliferation, inhibiting viral proliferation, enhancing the phagocytic activity of macrophages, and augmenting the cytotoxic activity of T lymphocytes. Interferons are divided into five major classes (alpha, beta, gamma, tau, and omega) and several subclasses (indicated by Arabic numerals and letters) on the basis of physicochemical properties, cells of origin, mode of induction, and antibody reactions. [interfere + -on]

Commercially available IFNs are produced by genetically altered colonies of Escherichia coli or Chinese hamster ovary cells, or are induced by controlled viral infection in pooled human leukocytes. Alpha IFNs have found the widest application in medicine. (The spelling alpha is used with respect to naturally occurring interferons. In compliance with international conventions for generic drug names, the spelling alfa appears in names of pharmaceutical formulations.) Alpha IFNs are used in the treatment of chronic hepatitis B and hepatitis C, hairy cell leukemia, chronic myelogenous leukemia, AIDS-related Kaposi sarcoma, melanoma, condylomata acuminata and recurrent respiratory papillomatosis due to human papillomavirus, and infantile hemangiomatosis. About 50% of patients treated for chronic hepatitis B with IFN-alfa show disappearance of hepatitis B_e antigen (HB_eAg) and reversion of alanine aminotransferase to normal. The response rate in chronic hepatitis C is lower (15-25%), but better results are achieved by using more aggressive therapy (daily rather than thrice weekly administration) and continuing it longer (a minimum of 12 months). Beta IFNs reduce clinical recurrences and progression of myelin damage in multiple sclerosis. Gamma IFN is effective in retarding tissue changes in osteopetrosis and systemic scleroderma and in reducing the frequency and severity of infections in chronic granulomatous disease. Administration of IFNs is parenteral (intravenous, intramuscular, subcutaneous, intranasal, intrathecal, or intralesional) and several weeks of treatment may be required before clinical response is noted. More than 50% of people treated with IFNs experience a flulike syndrome of fatigue, myalgia, and arthralgia. Gastrointestinal and CNS side-effects are also common, and marrow suppression may occur with prolonged treatment.

interferon

(ĭn′tər-fîr′ŏn′)n.1. Any of a group of glycoproteins that are produced by different cell types in response to various stimuli, such as exposure to a virus, bacterium, parasite, or other antigen, and that inhibit infection through mechanisms such as preventing viral replication or regulating the immune system.2. Any of a group of synthetic glycoproteins that are structurally similar to these compounds and are used therapeutically, especially as antivirals.

interferon

Cell biology A family of immune regulatory proteins–immunomodulators–produced by T cells, fibroblasts, and other cells in response to double-stranded DNA, viruses, mitogens, antigens, or lectins; IFNs ↑ the bactericidal, viricidal and tumoricidal activities of macrophages Types α–20 subtypes, IFN-β–2 subtypes, both produced by macrophages, IFN-γ, IFN-omega, IFN-tau Actions 1. Antiviral, causing those cells playing host to certain viruses–eg, rhinovirus, HPV, and retrovirus to produce proteins that interfere with intracellular viral replication.2. Antiproliferative, acting by unknown mechanisms, possibly ↓ translation of certain proteins, slowing cell cycling.3. Immunomodulatory, stimulating certain immune effects–T-cell activation, maturation of pre-NK cells, and ↑ phagocytosis and cytotoxicity by macrophages Adverse effects Flu-like symptoms, GI tract–N&V, anorexia, diarrhea, dysgeusia, xerostomia, neurologic—confusion, somnolence, poor concentration, seizures, transient aphasia, hallucinations, paranoia, psychoses, cardiopulmonary–tachycardia, dyspnea, orthostatic hypotension, cyanosis, hepatorenal–↑ transaminases, ↑ BUN, proteinuria, hematologic–neutropenia, thrombocytopenia Sx. See Biological response modifier, MAF, MIF.

in·ter·fer·on

(IFN) (in'tĕr-fēr'on) A class of small protein and glycoprotein cytokines (15-28 kD) produced by T cells, fibroblasts, and other cells in response to viral infection and other biologic and synthetic stimuli. Interferons bind to specific receptors on cell membranes; their effects include inducing enzymes, suppressing cell proliferation, inhibiting viral proliferation, enhancing the phagocytic activity of macrophages, and augmenting the cytotoxic activity of T lymphocytes. Interferons are divided into five major classes (alpha, beta, gamma, tau, and omega) and several subclasses (indicated by Arabic numerals and letters) on the basis of physicochemical properties, cells of origin, mode of induction, and antibody reactions.

interferon

a glycoprotein produced by cells in response to viral attack, whose function seems to be the triggering ofviral interference defence mechanisms in uninfected cells of the same species in which it was produced. Since it has been suggested that interferon might prove effective against viral diseases by inhibiting viral multiplication, and even some forms of cancer, strenuous efforts have been made to isolate sufficient quantities with which to run clinical trials. The problem of production has now been solved by GENETIC ENGINEERING but the results of trials are inconclusive, so far.

Interferon

A protein formed when cells are exposed to a virus. Interferon causes other noninfected cells to develop translation inhibitory protein (TIP). TIP blocks viruses from infecting new cells.Mentioned in: Ascites, Cervical Cancer, Herbalism, Traditional Chinese, Rhinitis

in·ter·fer·on

(IFN) (in'tĕr-fēr'on) A class of small protein and glycoprotein cytokines produced by T cells, fibroblasts, and other cells in response to viral infection and other biologic and synthetic stimuli.

Patient discussion about interferon

Q. aftrer completing interferon treatment for HCV it's showing up negitive in blood test,does it get any better? I completed Interferon treatment for HCV four years ago. It has come negitive in my blood work scence. Does it get any better? I;m haveing a hard time building my stamina back up to pre treatment Is there any hope of getting it back, my strenth and stamina? I'm 65 yrs. and counting. I'd like to count a lot longer. Thak You in advance, gffA. Unfortunately, the risk of chronic infection after an acute episode of hepatitis C is high. In most studies, 80 to 100 percent of patients remain HCV-RNA positive, and 60 to 80 percent have persistently elevated liver enzymes. The rate of spontaneous clearance of virus after it has persisted for at least six months is very low. In one study, for example, 142 HCV antibody-negative patients during eight years of follow-up, showed seroconversion (going from negative to positive) in 30 percent. You should keep getting tested on a regular basis, and hopefully your antibodies will remain negative. Meanwhile focus on living a otherwise healthy life. If you eat properyly and exercise often you can bulid up some energy that you feel you've lost.

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noun an antiviral protein produced by cells that have been invaded by a virus

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