宋内氏痢疾菌无毒株S7表达Vi抗原工程菌的构建

Construction of an Avirulent Shigella Sonnei Vaccine Strain Expressing Vi Antigen

将含有编码Ｖｉ抗原ＶｉａＢ基因片断的质粒转导进入宋内氏痢菌无毒株Ｓ７中，组建了重组菌株Ｓ７Ｖｉ。质粒电泳图谱显示重组菌株Ｓ７Ｖｉ中存在被转入的外源质粒带。重组株的生化特性没有改变。菌体凝集及Ｖｉ抗血清标记的ＳＰＡ菌液凝集反应证明在重组株的菌体表面，同时表达了Ｖｉ抗原和内氏痢疾菌的Ｏ抗原。以５×１０＾８ＣＦＵ、１０×１０＾８ＣＦＵ的重组株免疫近交系的ＬＩＢＰ小鼠。

A plasmid containing Via B gene fragment which encodes Vi antigen was transformed into an attenuated strain of Shigella Sonnei named S7,and the recombinent vaccine strain S7Vi was constructed.The biochemical and virulent characteristics of the strain S7Vi were similar with its vector.The results of bacterial agglutination tests showed that the recombinent strain had expressed both Vi antigen and O antigen of Shigella Sonnei on the cell surface.The efficiency of the strain was demonstrated in the mouse model.Vaccination with two doses of 500 million CFU or 1000 million CFU of S7Vi protected approximately 60-90% of the mouse challenged with the virulent Shigella Sonnei strain S63,and 25-40% with the virulent Salmonella Typhi strain Ty2.