Vi抗原影响产肠毒素大肠杆菌菌毛 在人伤寒沙门菌表面的装配

目的 观察人伤寒沙门菌Vi抗原对大肠杆菌菌毛抗原装配的影响。方法 利用体内、外同源重组系统，构建了VipR基因缺失突变的人伤寒沙门菌菌株，导致其Vi抗原的表达较相应野生菌株偏低。用包含产肠毒素大肠杆菌菌毛抗原基因的表达质料分别转化Vi表达弱化菌株和相应野生菌株，对两者表达的菌毛抗原进行含量分析。结果 产肠毒素大肠杆菌CS3、CFA－I在VipR突变体菌株表面的含量，均比在相应野生菌株表面的含量高。结论 Vi抗原的表达弱化可能有利于菌毛抗原在人伤寒沙门菌表面的装配。本研究结果对于产肠毒素大肠杆菌基因工程疫苗的构建有指导意义。

Effect of Vi antigen on assembly of colonization factor antigens from enterotoxigenic Escherichia coli on the cell surface of Salmonella typhi

Objective To study the effects of Vi antigen on assembly of colonization factor antigens from enterotoxigenic Escherichia coli on the cell surface of Salmonella typhi . Methods A Salmonella typhi mutant RH108 was constructed by homological recombination in vivo , in which VipR gene was partially deleted and so with low expression level of Vi antigen as compared with the corresponding wild type, RS406. The two bacteria strains were transformed by recombinant plasmids expressing coli surface antigen CFA I and CS3 from enterotoxigenic Escherichia coli . The concentrations of CFA I and CS3 expressed and assembled on the surface of RS406 and RH108 were titered by ELISA method. Results CFA I and CS3 were expressed and assembled better on the cell surface of RH108. Immuno gold labeled electroscope analysis gave same results. Conclusion Moderation of Vi antigen may boost expression and assembly of coli surface antigens from enterotoxigenic Escherichia coli on the surface of Salmonella typhi . This result may be useful for construction of effective vaccine against enterotoxigenic Escherichia coli with Salmonella typhi as antigens carrier.