Human interferon beta (165 residues), cysteine 17 is substituted with serine. Produced in E. coli, no carbohydrates, MW=18.5kD
Interferon beta upregulates the expression of MHC I proteins, allowing for increased presentation of peptides derived from viral antigens. This enhances the activation of CD8+ T cells that are the precursors for cytotoxic T lymphocytes (CTLs) and makes the macrophage a better target for CTL-mediated killing. Type I interferons also induce the synthesis of several key antiviral mediators including 2'-5' oligoadenylate synthetase (2'-5' A synthetase), beta-2 microglobulin, neopterin and protein kinase R.
Interferon beta-1b is a drug used for the treatment of relapsing/remitting multiple sclerosis. It has been shown to slow the advance of the disease as well as to decrease the frequency of attacks.
Interferon beta binds to type I interferon receptors (IFNAR1 and IFNAR2c) which activate two Jak (Janus kinase) tyrosine kinases (Jak1 and Tyk2). These transphosphorylate themselves and phosphorylate the receptors. The phosphorylated INFAR receptors then bind to Stat1 and Stat2 (signal transducers and activators of transcription)which dimerize and activate multiple (~100) immunomodulatory and antiviral proteins. Interferon beta binds more stably to type I interferon receptors than interferon alpha.