Yersinia enterocolitica ghost with msbB mutation provides protection and reduces proinflammatory cytokines in mice.

Abstract Yersinia enterocolitica is an important human pathogen. Yersiniosis, caused by Y. enterocolitica , has become more prevalent globally in recent years. Prevention of yersiniosis still remains a challenge, and an efficacious and safe vaccine that confers protection against this enteric pathogen needs to be developed. In this study, a novel vaccine based on the bacterial ghost, in combination with mutation of the Y . enterocolitica msbB gene, was developed and the immunopotency of this vaccine was evaluated in mice. Significant levels of IgG1/IgG2a antibodies and IL-4/IFN-γ cytokines were detected after mice were administered this vaccine intragastrically, indicating that a Th1/Th2-mediated mixed immune response was stimulated. Importantly, mutation of the msbB gene efficiently reduced secretion of the proinflammatory cytokines IL-1β, IL-6 and TNF-α, suggesting a reduction in inflammatory reaction caused by lipopolysaccharide. In addition, when challenged with a dose that was 100-fold the minimal lethal dose of the virulent wild strain of Y . enterocolitica , this mutated ghost vaccine was capable of eliciting the same effective protection (80%) in comparison with the non-mutated ghost strain, and the survival time was extended by at least two days. Together, our results demonstrated that this novel ghost bacterial strain could be used as a safe and effective vaccine against Y . enterocolitica .