Interferon

Interferon is a protein produced by animals in response to viral infections. It is a defensive mechanism by the body to prevent multiplication of the virus. The action of interferon was first demonstrated in 1957 by British virologist Alick Isaacs (1921-1967) and his Swiss colleague Jean Lindenmann. Isaacs was born in Glasgow, Scotland, in 1921, to a Russian Jewish family. He studied medicine at Glasgow University but found he preferred research to the actual practice of medicine.

Viral Interference

Early in his studies of influenza (flu) at the World Influenza Centre at the National Institute for Medical Research in England, Isaacs became interested in the viral interference phenomenon, first described in 1935. It was observed that an RNA virus in a cell inhibits (restrains) the growth of any other viruses in that cell. While trying to discover the mechanism by which this occurs, Isaacs found that the interference seemed to be caused by something inside the cell.

While working with the visiting Swiss scientist Jean Lindenmann in 1957, Isaacs found that chick embryos (developing eggs) injected with influenza virus released very small amounts of a protein that destroyed the virus. The protein also inhibited the growth of any other viruses in the embryos. Isaacs and Lindenmann named the interfering protein interferon.

It is now known that interferon is produced within hours of a viral invasion and that most living things, including plants, can make the protective protein. Interferon was initially seen as the cell's first line of defense against viral infections, and its discovery was expected to pave the way for successful treatment of viral diseases. Researchers soon found, however, that interferon is "species-specific." (Only human interferon, for example, will work in human beings.) The body also produces interferon in only small amounts, making it extremely expensive to obtain. These difficulties caused interferon research to inch forward at only a slow pace.

New Interest

The late 1960s saw renewed interest in interferon when Ion Gresser (1928-), an American researcher in Paris, discovered that the protein stopped or slowed the growth of tumors in mice and also stimulated the production of tumor-killing lymphocytes (white blood cells). Gresser and Finnish virologist Karl Cantell both developed a way to make interferon in useful amounts from human blood cells. Monoclonal antibodies, first produced in 1975, made large-scale purification of interferon possible. The mid-1980s saw the advent of genetically-engineered interferon, the first example of which was produced from bacteria by Swiss scientist Charles Weissmann in 1980.

Research of interferon's ability to kill cancer cells has yielded only mixed results. It has been successfully used, however, against leukemia and osteogenic sarcoma (a bone cancer). Interferon shows varied promise in treating one type of multiple sclerosis, melanoma, renal cell cancer, and a few AIDS-related Kaposi's sarcomas. Interferon is also used to treat viral diseases like rabies, hepatitis, and herpes infections.