Interferons

Interferons are a group of signaling proteins made and released by host cells in response to the presence of several viruses. In a typical scenario, a virus-infected cell will release interferons causing nearby cells to heighten their anti-viral defenses.

Types of Interferons

Interferons are named for their ability to "interfere" with viral replication. They are broadly classified into three categories: Type I, Type II, and Type III.

Type I Interferon

Type I interferons, which include Interferon-alpha (IFN-alpha) and Interferon-beta (IFN-beta), are produced in response to a viral infection. They stimulate cells to heighten their anti-viral defenses.

Type II Interferon

Type II interferon, also known as Interferon-gamma (IFN-gamma), is released by T cells and natural killer cells of the immune system. It is important for fighting bacterial and viral infections and for modulating the immune response.

Type III Interferon

Type III interferons, also known as Interferon-lambda (IFN-lambda), are a group of cytokines with antiviral activity. They are structurally similar to both type I and type II interferons.

Function

Interferons have several functions. They inhibit viral replication, increase antigen presentation to lymphocytes, and activate immune cells, such as natural killer cells and macrophages. They also increase the ability of uninfected host cells to resist new infection by virus.

Clinical Use

Interferons have been used clinically in the treatment of diseases such as Hepatitis C, Hepatitis B, Multiple sclerosis, and some types of Cancer.

Side Effects

Interferons can cause a range of side effects, including flu-like symptoms, anorexia, depression, and thinning of the hair. More serious side effects include damage to the heart and the thyroid gland.

See Also

• Cytokine
• Immune system
• Virus

Interferons Resources
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