Purification of Recombinant Human Alpha-2a Interferon Without Using Monoclonal Antibodies

This report describes a high-level expression of human alpha-2a interferon (IFNalpha-2a) in Escherichia coli and its pilot scale purification by using a monoclonal antibody-independent chromatographic procedure that is based on anion-exchange, cation-exchange, hydrophobic interaction, and gel filtration. The recombinant E. coli produced much more IFNalpha-2a in a soluble form, when cultivated at low temperatures than at high-temperature fermentation. However, if the bacterial growth was taken into consideration, fermentation at 30degreesC seemed optimal for the interferon production. By using our new protocol, we recovered approximately 160 mg of IFNalpha-2a with a specific activity of 3.59x10(8) IU/mg from 201 of the broth. The gel permeation chromatographic and SDS-PAGE indicated that the interferon preparation was purified to homogeneity and was of the correctly folded fast-migrating monomer.