Interferons

Interferons are antiviral, species-specific proteins that mammalian cells release when infected by a virus; based on their structure they are grouped into alpha, beta and gamma types, and they work by stimulating nearby cells' own DNA to produce antiviral enzymes that block viral replication. Discovered by Alick Isaacs and Jean Lindemann in 1957, interferons have real therapeutic value against cancer, AIDS, multiple sclerosis, hepatitis C and herpes zoster, but purifying them directly from blood — as with Factor VIII — would require impractically large volumes. Recombinant production solves the supply problem, though interestingly the preferred host is not E. coli but the yeast Saccharomyces cerevisiae, because bacteria lack the cellular machinery to glycosylate (attach sugar groups to) the protein correctly while yeast, being eukaryotic, ca …