[Construction of attenuated Salmonella typhimurium vaccine strain expressing Helicobacter pylori catalase and observation on its protective immunity]

Abstract

Objective: To investigated the effect of attenuated Salmonella typhimurium vaccine strain expressing Helicobacter pylori (Hp) catalase (KatA) on protection against Hp infection.

Methods: Recombinant plasmid expressing KatA was constructed. Expression of KatA was induced with IPTG, and analyzed by SDS-PAGE and Western blot. The recombinant plasmid were introduced into attenuated Salmonella typhimurium SL3261 strain to construct live oral vaccine strain. C57BL/6 mice was orally immunized with this vaccine strain and then given orogastric challenge with live Hp Sydney strain. The stomach samples were submitted to a rapid urease test and quantitative culture.

Results: The SDS-PAGE showed a dominant additional protein with molecular weight of 79kDa which could specially react with antibody against GST and accounted for 19% of total bacteria proteins. Animal experiment indicated that this vaccine strain could protect mice against Hp infection.

Conclusion: Attenuated Salmonella typhimurium vaccine strain expressing KatA could induce effective immune response in protection against Hp infection,which may play an important role in preventing and treating Hp infection and related diseases.