Construction of live recombinant attenuated Salmoella typhimurium vaccine candidate strains expressing ureB and ureB-hspA from Helicobacter pylori

Objective To construct live recombinant attenuated Salmoella typhimurium vaccine strains expressing ureB and ureB-hspA from H.pylori. Methods ureB gene and ureB-hspA fusion gene were amplified by PCR and cloned into a prokaryotic expression plasmid pTrc99A-asd. The recombinant plasmid was identified and then used to transform the attenuated S.typhimurium X3730 and S.typhimurium X4072. The recombinant vaccine strain was analyzed by SDS-PAGE and Western blot. Immunize mice with the recombinant bacteria either orogastrically (o.g) or intranasally (i.n). Results The ureB and ureB-uspA were expressed in the recombinant vaccine strain X4072 as proteins of 64kD and 77kD. Western blot analysis of UreB and UreB-HspA recombinant proteins confirmed that those specially recognized by serum from H.pylori-infected patients. Antibodies against H.pylori whole-cell sonication were detected in the sera of mice immunized with recombinant bacteria either o.g or i.n; simultaneously sIgA against H.pylori also detected in the intestine. Conclusion Recombinant live attenuated S.typhimurium vaccine strains expressing H.pylori UreB and UreB-HspA will help to develop an oral recombinant live vaccine for the control of H.pylori-related diseases in humans.