[Expression and purification of IFNbeta-HSA fusion protein in Pichia pastoris]

In order to obtain enough fusion protein for developing preclinical studies of IFNbeta-HAS, we screened Pichia pastoris transformants expressing high-level protein by immunology method. The yield of IFNbeta-HSA was about 500 mg/L by fed-batch fermentation. The purity of IFNbeta-HSA reached 96% through the steps of ultrafiltration, Blue Sepharose FF, Ni2+-IMAC and DEAE Sepharose FF. Analysis of Western blotting showed that IFNbeta-HSA had the antigenicity of IFNbeta and HSA. The specific activity was about 1.96 x 10(7) IU/mg by standard survival activity test on WISH cells challenged with VSV virus. This study provided a method to produce IFNbeta-HSA.