Abstract: Methods are provided using high pressure to treat aggregated interferons, to reduce the aggregate content of interferon material. In particular, recombinant human interferon-? may be so treated. Multiple strategies may be used in combination to make nonglycosylated IFN-? more amenable to high pressure treatment. When coupled with purification techniques, these strategies singly or in combination provide a low aggregate or substantially aggregate free, biologically active solution. In certain aspects, pharmaceutical compositions containing nonglycosylated interferon having less than about 5 weight percent of protein aggregation are provided.

Abstract: High pressure to treat aggregated interferons, particularly recombinant human interferon-?, to reduce the aggregate content of interferon material. Highly pure, soluble monomeric recombinant interferon-? is prepared in representative embodiments. Multiple strategies may be used in combination that make nonglycosylated IFN-? more amenable to high pressure treatment. It has been found that refolding yields of high pressure treatment can be significantly improved by use of a combination of strategies, including, or example a pre-treatment of the IFN-? that involves solubilizing and then precipitating the protein. This pre-treatment is particularly effective with respect to recombinant IFN-? inclusion bodies recovered from host cells such as E. coli cells. According to another strategy, refolding under high pressure is much more effective when the refolding reagent incorporating the IFN-? incorporates a zwitterionic surfactant and/or a cholate salt.