Interferon, a small protein containing fewer than two hundred amino acids, is an interesting example of a biologically active polypeptide. There are three classes of interferon, labeled by the first three letters of the Greek alphabet. Interferon- α is used to treat leukemia, hepatitis B and C, and Kaposi's sarcoma. Interferon- γ finds use as a treatment for multiple sclerosis and interferon- γ has applications in treating a rare genetic disorder called granulomatous disease.
Cells within the body synthesize interferon when experiencing stress from incidents such as viral attack. When interferon is released into the bloodstream by an infected cell, it helps signal an immune response to the invader. Other mechanisms that interferon activates in the fight against viral infections are less understood. It is hypothesized that in addition to signaling the immune system they somehow inhibit the ability of viruses and tumor cells to reproduce. Research to further the understanding of how interferon works is inhibited by the fact that, aside from humans, only a few other animals have cells that make interferon. Many studies of how drug molecules work are carried out first with animals, but for interferon, this type of study is less productive.
Dr. Alick Isaacs and Dr. Jean Lindenmann discovered interferon in 1957 in Great Britain. In an experiment, they mixed live viruses with egg membranes and unexpectedly found that the viruses did not grow. They did not know what caused this observation and simply indicated something interfered with the virus, so the term "interferon" was coined. They eventually identified the polypeptide and were able to isolate it from various cells, including those taken from calves, monkeys, and humans.
Interferon is produced naturally in very small quantities. When it originally was introduced as a form of medical treatment, the expense associated with isolating the compound from sources such as blood made it prohibitively expensive. Interferon became viable as a medical intervention only through the application of genetic engineering. The gene that tells a cell how to construct interferon is introduced into Escherichia coli bacteria. These bacteria are grown in culture and they produce the interferon. Because the bacteria can be grown relatively quickly, large quantities of interferon can be generated with this method. While many people tend to react to the phrase "genetic engineering" with some fear, interferon represents an excellent example of how advances in medical treatment were made possible only by its application.
Becker, Yechiel, ed. (1984). Antiviral Drugs and Interferon: The Molecular Basis of Their Activity. New York: Kluwer.
Cantell, K. (1998). The Story of Interferon: The Ups and Downs in the Life of a Scientist. River Edge, NJ: World Scientific.
Lindenmann, J., and Schleuning, W. D., eds. (1999). Interferon: The Dawn of Recombinant Protein Drugs. New York: Springer-Verlag.