Interferons (IFNs) are a group of signalling proteins produced by a variety of cells in the inflammatory response to infections. IFNs are made and released by host cells in response to the presence of viruses, bacteria, or unknown nucleic acids.

In a typical scenario, a virus-infected cell will release interferons which will activate other cells causing nearby cells to heighten their anti-viral defences and destroy invading viruses, pathogens or other invaders.

Their production is triggered by the immune system in response to pathogens or cytokines. Once triggered, they induce numerous molecular changes that affect cellular responses including cell growth and inflammation. When released, it sets off a series of reactions in nearby cells to help them defend against the infection.

There are three basic forms of interferon. These are alpha and beta, also known as type 1, while gamma is known as type 2. Each form of interferon has different effects on the body.