Interferons (IFNs) are natural proteins produced by the cells of the immune system of most vertebrates in response to challenges by foreign agents such as viruses, bacteria, parasites and tumor cells.There are three major classes of interferons that have been described for humans according to the type of receptor through which they signal:

All type I IFNs bind to a specific cell surface receptor complex known as the IFN-alpha receptor (IFNAR) that consists of IFNAR1 and IFNAR2 chains. Interferon type II Bind to IFNGR. Interferon type III Signal through a receptor complex consisting of IL10R2 and IFNLR1.