肠毒素源性定居因子CS6在减素伤寒沙门氏菌中表达及免疫原性的研究

将编码肠毒素源性大肠杆菌定居因子抗原ＣＳ６基因克隆到ｐＸＬ６７０，转化ａｓｄ基因突变的Ｅ．ｃｏｌｉ Ｘ６０９７，获得重组质粒ｐＳＳ６４，再将后者转化至减毒的△ａｒｏＡ、△ａｒｏＣ、△ａｓｄ伤寒沙门氏菌，构建了无药物抗性且稳定的大肠杆菌和伤寒双价菌苗候选株。小鼠腹腔免疫和攻击实验表明，该菌株对伤寒沙门氏菌毒株的攻击具有良好的保护作用。家兔免疫实验证明，该菌株能产生抗ＣＳ６和伤寒菌Ｖｉ抗原的血清抗体。

Stable expression and immunogenicity in a attenuated Salmonella typhi strain of coli surface antigen-6 of enterotoxigenic Escherichia coli]

A gene fragment encoding for surface antigen CS6 of enterotoxigenic of Escherichia coli has been cloned into the plasmid pXL670, a new recombinant plasmid pSS64 was obtained by transforming E. coli X6097 with asd gene deletion. A safe and effective E. coli/S. typhi bivalent candidate vaccine was constructed by introducing pSS64 into delta aroA, delta aroC, delta asd Salmonella typhi. The vaccine strain is still stable in the absence of antibiotics. Animal tests demonstrated that this strain, when administered subcutaneously in mice, could provide significant protection against the intraperitoneal challenge from wild S. typhi Ty2. Immunization of rabbit with this strain raised specific antibody responses against CS6 and Vi antigen of S. typhi. This study lays the foundation for the construction of a new E. coli/S. typhi bivalent live oral vaccine.