Human type I interferons (IFNs) are a large subgroup of interferon proteins that help regulate the activity of the immune system. Interferons bind to interferon receptors. All type I IFNs bind to a specific cell surface receptor complex known as the IFN-¦Á receptor (IFNAR) that consists of IFNAR1 and IFNAR2 chains. The IFN-¦Â proteins are produced in large quantities by fibroblasts. They have antiviral activity that is involved mainly in innate immune response. Two types of IFN-¦Â have been described, IFN-¦Â1 (IFNB1) and IFN-¦Â3 (IFNB3) (a gene designated IFN-¦Â2 is actually IL-6). IFN-¦Â1 is used as a treatment for multiple sclerosis as it reduces the relapse rate. Furthermore, IFN-¦Â1 can bind to a IFNAR1-IFNAR2 heterodimeric receptor, and can also function with IFNAR1 alone and independently of Jak-STAT pathways.