乙肝PreS_2抗原决定簇和霍乱毒素B亚基基因的融合与表达

通过全化学法按大肠杆菌密码偏性合成了乙肝炎病毒（ＨＢＶ）前Ｓ２抗原（ＰｒｅＳ２）抗原决定簇基因，与霍乱毒素Ｂ亚基基因的３’端融合。重组质粒转化大肠杆菌后融合基因得到高效表达，表达量达３０μｇ／ｍＬ，表达产物９５％以上分泌到胞外。表达的融合蛋白能与神经节苷脂ＧＭ１结合，说明融合蛋白保持了霍乱毒素Ｂ亚基（ＣＴＢ）的基本高级结构和生物学功能；酶联免疫吸附实验证明融合蛋白具有ＣＴＢ和ＨＢＶＰｒｅＳ２的抗原性；应用亲和层析纯化后得到了电泳纯融合蛋白制品，为研究融合蛋白免疫原性并进一步构建基因工程肽苗奠定了基础。

Gene Fusion and Expression of Cholera Toxin B Subunit with HBV preS_2 Epitope

polynucleotides encoding 120-145aa epitope of HBV PreS2 were chemically synthesized according to the codon usage frequency of E. coli and genetically fused to the 3'end of cholera toxin B subunit gene. The fused gene was highly-expressed (about 30 μg/mL) in E. coli, and more than 95% of the fusion protein could be secreted into the medium. The fusion protein expressed was purified by affinity chromatography. It had been demonstrated that the chimera obtained could bind ganglioside GM1, which indicated that it retained the biological function of cholera toxin B subunit.The chimera had the antigenicity both for cholera toxin B subunit and HBV PreS2 confirmed by Enzyme Linked Immunosorbent Assay. This work provided a sound basis for further studies on the immunogenicity of fusion protein and on the construction of engineered peptide vaccine.