A novel recombinant multi-epitope protein against Brucella melitensis infection

• We employed bioinformatic tools to predict B-cell epitopes and T-cell epitopes.
• We assembled these predicted different epitopes together to construct a recombinant multi-epitope protein.
• The recombinant antigen and vaccine strain M5 provided equal protection against B. melitensis 16 M infection.

Live, attenuated Brucella vaccines are considered effective but can induce abortions in pregnant animals and are potentially infectious to humans. There is a strong need to improve the immunoprotective effects and safety of vaccines against Brucella. Currently, subunit vaccines have been demonstrated to be safe and efficacious alternatives in both humans and animals. In this study, we employed bioinformatics tools to predict B and T cell epitopes to aid development of a novel recombinant multi-epitope antigen for brucellosis vaccination. To evaluate the protective capacity of the recombinant antigen, the antigen’s efficacy was studied in a mouse model of brucellosis. Our results indicated that BALB/c mice immunized with this recombinant multi-epitope antigen showed mixed Th1-Th2 immune responses with high levels of specific IgG and exhibited high degrees of IFN-γ and IL-6 and significantly higher CD3, CD4, and CD8 frequencies compared to the control group. The recombinant antigen and vaccine strain M5-90 also provided protection against Brucella melitensis 16 M infection. Using bioinformatics tools to develop candidate vaccines is a promising strategy for the development of Brucella vaccines.