CS3菌毛抗原和霍乱毒素B亚基在人伤寒菌中的表达

通过体内外重组的方法，构建了人伤寒菌流行株Ｔｙ２的△ａｒｏＡ，△ａｒｏＣ和ａｓｄ＾－基因缺失突变体（ＲＳ４１７）作为抗原载体菌：同时，构建包含ａｓｄ基因的表达质粒ｐＹＸ１０２，与ＲＳ４１７一起，构成宿主－载全平衡致死系统，用于在没有抗生素条件选择的情况下，稳定表达克隆在表达质粒上的外源抗原基因，将肠毒素性大肠杆菌的菌毛抗原ＩＩＩ（ＣＳ３）基因和霍乱弧菌毒素Ｂ亚基（ＣＴＢ）基因分别克隆至ｐＹＸ１０２

Simultneous Expression of CS3 Colonization Factor Antigen and Cholera Toxin B Subunit in Salmonella typhi

A host plasmid balancing system was established based on asd gene in an avirulent strain of Salmonella typhi to express enterotoxigenic E.coli surface antigen CS3 and V.cholerae toxin subunit B(CTB). The plasmid can be stably maintained in the host and can express CS3 and CTB in the host cell without any antibiotic selection, although expression level and growth characteristics of the recombinant strain expressing either CS3 or CTB are superior to that of the recombinant strain which expresses both of the antigens. Antibo dies against CS3 and CTB can be detected in sera of mice immunized with recombinant bacteria either orally or subcutaneously, and mice immunized subcutaneously can be protected from challenging with virulent strain of Salmonella typhi. This work may be helpful in constructing multivalent recombinant vaccines for prevention of bacterial diarrhea.