乙型肝炎病毒前S2抗原决定簇（HBVPreS2epitope）与乙型肝炎病毒核心抗原（HBcAg）的基因融合与表达

乙肝前Ｓ２（ＨＢＶＰｒｅＳ２）肽段由５５个氨基酸组成，其Ｎ端肽段含Ｔｈ和Ｂ细胞抗原决定簇。我们将化学合成的ＰｒｅＳ２ｅｐｉｔｏｐｅ（１２０－１４５）基因与ＨＢｃＡｇ基因不同位点进行融合，融合基因在大肠杆菌中获得表达，并对融合蛋白进行了纯化。经ＥＬＩＳＡ和Ｗｅｓｔｅｒｎ－ｂｌｏｔ实验表明，融合蛋白具有ＰｒｅＳ２和ＨＢｃＡｇ两者的抗原性。此外，研究还表明，强启动子能使表达水平有一定提高。

FUSION AND EXPRESSION OF HEPATITIS B VIRUS PreS2EPITOPE(120-145)AND HBcAg GENES

BV PreS2 consists of 55 amino acids of which the 26 amino acids at the N terminalare the Th cell and B cell epitopes. HBcAg gene including partial PreC gene was fused withchemically synthesized PreS2 epitope(120-145) gene at different sites.The fusion proteins wereexpressed in E.coli and purified by affinity chromatography.The antigenicity of differentfusion proteins were studied by ELISA and Western-blot.It was found that best retention ofantigenicity of both HBcAg and PreS2 was obtained with fusion at position 144 at the Cterminus of HBcAg after removal of the arginine rich region. In addition, the expression levelof fusion proteins could be increased with tac promoter instead of lac promoter and differenthost strains have little influence on the expression level of the fusion protein.