A组轮状病毒VP6与霍乱毒素B亚基融合蛋白在大肠杆菌中的表达及生物活性分析

利用霍乱毒素B亚基 (CholeratoxinBsubunit,CTB)的免疫载体作用 ,将轮状病毒相关抗原引入口服免疫体系 ,可激起有效的粘膜免疫反应 ,这里报道了CTB基因与A组轮状病毒地方株T114VP6全基因的融合 ,并在大肠杆菌BL21(DE3 )中进行了融合蛋白的表达。在IPTG诱导下得到分子量为 5 6kD的融合蛋白 ,表达量占菌体蛋白的15 %。分别用抗CT的抗体和抗A组轮状病毒的高价免疫血清进行WesternBlot检测 ,结果证明融合蛋白CTB VP6保留了天然霍乱毒素B亚基及轮状病毒VP6的抗原性。G_M1-ELISA检测表明 ,复性后的融合蛋白具有与神经节苷脂GM1 结合的能力。

A Fusion Protein of Rotavirus VP6 and Cholera Toxin B Subunit:Expression in Escherichia coli and Analysis of Biological Activities

Rotavirus infection is a major cause of dehydrating diarrhea in infants worldwide. The non-toxic cholera toxin B subunit(CTB), known as an immunomodulatory carrier, might help to stimulate mucosal immune response when coupled to rotavirus antigens in oral immunization. Here we report for the first time the construction of a translational fusion of CTB gene 5' to the VP6 gene of a human rotavirus A(field strain T114), and expression of the CTB-VP6 fusion protein in E. coli BL21(DE3). The expressed fusion protein has a molecular weight of 56 kD, as expected, and accounts for about 15% of the total E. coli protein. Western blottings with the hyperimmune serum against rotavirus strain WA and the antibody against cholera toxin indicated that the fusion protein retains the antigenicity identical to the native CTB and VP6. The GM1-ELISA analysis proves that the renatured CTB-VP6 has strong affinity for GM1 ganglioside.