Effect of P39 gene deletion in live Brucella vaccine strains on residual virulence and protective activity in mice

Abstract

The 39-kilodalton protein (P39) has previously been shown to be an immunodominant protein in Brucella infections. P39 gene deletion mutants of vaccine strains Brucella abortus S19 and Brucella melitensis Rev. 1 were constructed by gene replacement. This deletion did not significantly modify the residual virulence of both vaccine strains in CD-1 mice. CD-1 mice vaccinated with the parent or mutant strains were protected against a virulent challenge. Mutant vaccine strains devoid of P39 could provide a means for differentiating vaccinated from infected animals.