Construction of a Salmonella typhimurium vaccine strain expressing Vibrio cholera CT-B and LPS-O antigen

Abstract

The genes encoding V. cholera CT-B and LPS-O antigens were simultaneously inserted into the vector plasmid pYA248. The resulting recombinant plasmid pMG306 was transformed into the delta cya delta crp delta asd attenuated S. typhimurium vaccine strain x4072, and the live vaccine strain x4072 (pMG306) was constructed. This vaccine strain could secrete a specific CT-B antigen. Meanwhile, LPS-O antigens of both V. cholera and S. typhimurium were expressed on the cell surface. Mouse intraperitoneal immunization and subsequent challenge trial indicated that x4072 (pMG306) provided good protection against virulent V. cholera. This study has laid the foundation for the development of a new cholera-typhoid bivalent live oral vaccine.