The present invention provides a
salmonella mutant strain capable of efficiently stimulating hosts to produce immune responses against
shigella flexneri 2
a serotype O
antigen polysaccharides, and a construction method and an application of the
salmonella mutant strain, and belongs to the technical field of bioengineering. The provided
salmonella mutant strain has the following
gene deletion mutations
delta-fliC,
delta-fljB,
delta-ompA, delta-ompC and delta-ompD, a
gene rfbP that is conducive to expression of
heterologous O
antigen polysaccharides is knocked out, and at the same time, expression plasmids capable of completely expressing the
shigella flexneri O
antigen polysaccharides are transferred. A preservation number of the salmonella
mutant strain is CCTCC NO:M 2020142 and the salmonella
mutant strain is preserved in the China Center for Type Culture Collection. By modifying an outer
membrane structure of the salmonella, the salmonella
mutant strain is more efficient to be used asa
polysaccharide presentation carrier. At the same time, the O antigen polysaccharides of the
shigella flexneri are expressed in the outer membrane of the salmonella, outer membrane vesicles are purified, the salmonella mutant strain can efficiently stimulate the hosts to produce the immune responses and secrete the outer membrane vesicles, thereby presenting
heterologous polysaccharide antigen as a vaccine, and the salmonella mutant strain can be effectively used for prevention and treatment of shigella infection.