Purification And Immune Effect Of Hepatitis B Virus PreS2(epi) S Protein Expressed In Pichia Pastoris

objective To purify the hepatitis B virus ( HBV ) preS2 (epi) S protein expressed in Pichia pastoris and study its Oimmune effectMethods Induce recombinant Pichia pastoris containing preS2 (epi) S gene with methanol, and purify the expressed.product by sucrose zonal centrifugation, Butyl-S-Sepharose 4FF hydrophobic and DEAE-Sepharose Fast Flow ion exchange chromatogram-phy and identify by SDS-PAGE and Western blot Prepare vaccine with the purified protein and perfor potency test in mice. Determ inemthe serum antibody concentration of m ice by R I and calculate ED50 and relative potency Test the antibody against preS2 (epi) S byA.ELISA.Results The purified preS2 (epi) S protein with a relative molecular mass of about 27 000 reacted with specific antibody The.ED50 of 2 batches of vaccine prepared with the purified protein were 0.35 and 0.48μg /m l respectively, while that of reference vaccinewas 0.52μg /m l The mean serum antibody concentrations induced by the 2 batches of vaccine were 808 and 784 m I /m l respectively,.Uwhile that by reference vaccine was 312 m I /m l The relative potencies of the 2 batches of vaccine were 1.5 and 1.1 respectively Both the 2 batches of vaccine induced antibody against preS2 in immunized mice.Conclusion The purification method was practical and effective, and the purified preS2 (epi) S protein showed good immunogenicity compared with S protein.