Evaluation of a recombinant bacillus calmette-guérin vaccine expressing P39-L7/L12 of Brucella melitensis: An immunization strategy against brucellosis in BALB/c mice

Abstract

Brucellosis is a chronic infectious disease caused by bacteria from the genus Brucella. It has a serious global economic impact, and poses a threat to public health. Ideally, vaccines should exhibit a safe profile as well as enhanced protective efficacy. However, there are no licensed vaccines available for humans against brucellosis. In this study, for the first time, a recombinant BCG (rBCG) vaccine expressing the P39-L7/12 fusion protein of Brucella melitensis against brucellosis was constructed. The rBCG vaccine elicited strong antigen-specific humoral and T cell-mediated immunity in vivo. The rBCG vaccine also induced a significant level of protection following challenge with a virulent strain of B. melitensis M28 in BALB/c mice. Furthermore, the protection level induced by the rBCG vaccine was significantly higher than that induced by BCG. Collectively, these results suggested that rBCG vaccine acted as a suitable vaccine candidate and a new strategy against human brucellosis.