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

This report describes a high-level expression of human alpha-2a interferon (<TEX>$IFN{alpha}-2a$</TEX>) 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 <TEX>$IFN{alpha}-2a$</TEX> 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 <TEX>$30^{circ}C$</TEX> seemed optimal for the interferon production. By using our new protocol, we recovered approximately 160 mg of <TEX>$IFN{alpha}-2a$</TEX> with a specific activity of <TEX>$3.59{ imes}10^8$</TEX> 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.