What is an interferon?
Interferon is a protein released by many cells in the body in response to various stimuli. There are two classes of interferons. Type I interferons are proteins that are produced in the body in response to a viral infection. In fact, these interferons are an individual's first defense: when the virus reaches other cells, it protects them from infection. When an individual has an infection with influenza virus, the headaches, chills, fever, muscle pain, aches are actually due to the production of interferon. You might say that when you start getting some of these symptoms, you should be grateful because you have something actually attacking the infection. Human interferons that are classified as the Type I are the interferon-alphas, of which there are 12, the interferon-beta and the interferon-omega. The Type II interferon is involved in controlling immune functions in the body and is not produced by viral infection. Interferon-gamma is the only Type II interferon.
How does interferon work in viral diseases?
Interferon prevents cells from infection from many, but not all, viruses. If a cell is treated with interferon, interferon changes the properties of that cell and can prevent the virus from replicating in that cell and leading to the infection of surrounding cells. It does this by a wide variety of mechanisms that vary from virus to virus and from cell to cell. Remarkably, the mechanism also varies from species to species, such as mice and humans, which makes it hard to predict how it will work in humans based on animal studies.
The interferon-alphas are used to treat viral diseases. They're approved by the Food and Drug Administration (FDA) for the treatment of chronic hepatitis B and chronic hepatitis C. They have also been approved for the treatment of papilloma virus infections, which cause genital warts. So those are two of the major viruses that are treated therapeutically with interferon.
