They are natural antiviral glycoproteins. They were called so because they interfere with replication of the virus in tissue culture. Interferons are of three major classes: alpha synthesized by leucocyte, beta produced by fibroblasts and gamma formed by lymphocytes. The exogenous interferon used clinically is alpha interferon produced by using recombinant DNA technology.
Mechanism of action:
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The natural interferons attach to surface receptor on the membrane of infected cell and then inhibit synthesis of protein and DNA that block viral replication. Also interferon blocks viral assembly and release.
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Interferon is able to suppress cell proliferation.
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Interferon has immunomodulating effects. It enhance phagocytosis by macrophages and increases the cytotoxicity exerted by lymphocytes
Therapeutic uses:
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Treatment of viral infections, especially, chronic hepatitis B and C viruses and prevents chronic liver toxicity, AIDS and genital (venereal) warts.
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Human cancer shows some response to interferon e.g. certain leukemias, lymphomas and laryngeal papillomatosis.
Adverse effects:
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Flu-like symptoms: Fatigue, depression, muscle weakness, weight and appetite loss, and change in thyroid function and cardiotoxcity. like Rifampin side effect
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High dose or chronic therapy causes bone marrow suppression, neurotoxicity and progressive fatigue.
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Plasma concentration of hepatic enzymes increase.
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The metabolism of other drugs can be reduced by interferon action on microsomal enzyme.