Interferons

Interferon was discovered by Alick Isaacs and Jean Lindenmann in 1957. It was originally thought that interferon could be used as a general anti-viral agent and in anti-cancer therapy. There are many different types of interferons, now known as interferons “alpha,” “beta,” “gamma” and “lambda,” with different cellular receptors and modes of action, and there are possibly 24 different types of alpha interferon. Independently and simultaneously, a group of Japanese scientists found an “interfering factor,” which upon subsequent analysis turned out to be interferon, probably of the alpha type. The interferon alpha gene was the first mammalian gene to be cloned in a bacterial system and became the prototype for gene cloning technology. Until the cloning of the interferons in Escherichia coli, and expression of the interferon genes in mammalian cells in culture, it was impossible to obtain enough material for clinical use. Interferon today is predominantly used in the treatment of hepatitis B and C, leukemia and Kaposi’s sarcoma. As an anti-viral agent, interferon has not lived up to its initial promise, since in vitro most viruses block the activity of interferon and clinical trials have given inconclusive results with severe side effects. Interferon induces hundreds of genes in vivo and in vitro, each interferon producing overlapping and distinct gene profiles. The mechanism of both interferon induction and anti-viral response is complicated and involves the interaction of many regulatory molecules. Interferon is now known to be a component of the large family of cytokines or interleukins.