Interferon alpha (IFN-α) cytokines belongs together with IFN-β to the type I interferon family, and is part of a cluster of proteins sharing more than 95% homology. IFN-α proteins are produced by several leukocytes, especially plasmacytoid dendritic cells, and share with all type I IFNs the same dimeric receptor (IFN-α R1/R2). IFN-α proteins induce a broad innate response to viral infections, but can also show immunomodulatory activities. IFN-α plays also a role in induction of fever and modulation of pain, by affecting the thermosensitivity of the hypothalamus and inducing prostaglandin-E2 release. An increased expression of IFN-α at tumor site favors dendritic cell activation and cytotoxic activity. IFN-α is usually produced as recombinant protein in two variants: IFN-α2a and IFN-α2b.
