Interferons (IFNs) are low molecular weight proteins that belong to the class of glycoproteins known as cytokines. IFNs are part of the non-specific immune system and are produced by a variety of cells as a first line of defense against viral infections. They are released by host cells in response to the presence of pathogens such as viruses, bacteria, parasites or tumor cells. Host symptoms, such as aching muscles and fever, are related to the production of IFNs during infection.
Interferons exhibit a wide range of biological activities that include:
Interferons are also important in drug therapy for many diseases involving the immune system. The mechanism of action by which interferons work is complex and advances in medicine and our understanding of the role of interferons will make a substantial impact on how diseases will be treated in the future.
There are three types of interferons known to date. IFNs are classified as Type I, II or III based on receptor complex recognition and protein structure.
- Type I [IFN-αR1 / IFN-αR2]: alpha, beta, delta, epsilon, kappa, nu, omega, tau
- Type II [IFN-γR1 / IFN-γR2]: gamma
- Type III [IL-28 αR / IL-10 R2]: lambda