A live attenuated strain ofYersinia pestis[delta]yscBprovides protection against bubonic and pneumonic plagues in mouse model

To develop a safe and effective live plague vaccine, the δyscBmutant was constructed based onYersinia pestisbiovarMicrotusstrain 201 that is avirulent to humans, but virulent to mice. The virulence, immunogenicity and protective efficacy of the δyscBmutant were evaluated in this study. The results showed that the δyscBmutant was severely attenuated, elicited a higher F1-specific antibody titer and provided protective efficacy against bubonic and pneumonic plague in mouse model. The δyscBmutant could induce the secretion of both Th1-associated cytokines (IFN-γ, IL-2 and TNF-) and Th2-associated cytokines (IL-4 and IL-10). Taken together, the δyscBmutant represented a potential vaccine candidate based on its ability to generate strong humoral and cell-mediated immune responses and to provide good protection against both subcutaneous and intranasalY. pestischallenge.