[Effects of the deletion of RsbV gene on virulence of Listeria monocytogenes].

Objective: To study the effect of RsbV gene deletion on the virulence of Listeria monocytogenes.

Methods: The fragment with RsbV deletion was generated by gene overlap extension PCR (SOE-PCR) and the mutant with RsbV deletion was obtained by homologous recombination based on the wild strain LM-XS5. The differences in virulence between the two strains were determined by LD50, bacterial counts in liver and spleen, and qRT-PCR experiments.

Results: LD50 of the RsbV gene-deleted strain was 10(4) higher than that of the wild strain. The numbers of gene-deleted strain in the mouse's liver and spleen were significantly fewer than that of the wild strain (P < 0.05). Results of qRT-PCR show that four virulence factors' expression levels of the RsbV gene-deleted strain were significantly lower than that of the wild strain (P < 0.05). The RsbV gene-deleted strain induced a strong immune response in mice against the wild strain.

Conclusion: RsbV regulates the expression of four virulence gene (inlA, LLO, PlcA and PrfA) of Listeria monocytogenes; The virulence of the RsbV gene-deleted strain is significantly reduced, but it still has good immunogenicity.