Purification and Characterization of Recombinant Hepatitis B Virus Surface Antigen SS1 Expressed in Pichia pastoris.

The purification of recombinant hepatitis B surface antigen, SS1 protein, expressed in Pichia pastoris, and the investigation of its physiochemical characters and immunogenicity were described here. Employing McAb immunoaffinity chromatography, this protein was purified to purity of 95%. The results of ELISA and Western blotting showed good antigenicity of this purified SS1 protein. CsCl gradient centrifugation and electron microscopy assay proved that this purified protein could be assembled into particles similar to the HBV subviral particles. Strong antibody responses against both the HBs and PreS1 epitopes were induced in BALB/c mice immunized with this purified protein. The simultaneous injection of a CpG adjuvant induced a Th1-like immune response against both the HBs and PreS1 epitopes.