Protective Immunity of a Novel Multi-Epitope Vaccine Encoding OMP31, TF, BLS, SOD, BP26, and L9 Against Brucella spp. Infection.

BACKGROUND

Brucella is a type of bacteria that causes a disease known as brucellosis in both humans and animals. Many different vaccine formulations are available for this disease; however, vaccines based on epitopes have shown to be effective, especially in combating this pathogen. In the present study, we designed a multi-epitope vaccine against brucellosis using a chimeric protein that combines segments from various Brucella proteins known to contain both B- and T-cell epitopes.

METHODS

In this study, a vaccine candidate was developed using multiple epitopes derived from various proteins, including OMP31, TF, BLS, SOD, BP26, and L9. These epitopes were selected based on their high density of both B-cell and T-cell epitopes. The construct of the vaccine candidate was inserted into a pEGFP-N1 vector and introduced into HEK-293T cells. Subsequently, the vaccine was tested on different groups of mice; some received the expressed protein in E. coli, while others received the DNA vaccine candidate. An ELISA assay was employed to evaluate the humoral immune response.

RESULTS

Both the MEB protein (Pro/Pro) and pCI-MEB plasmid/MEB protein (DNA/Pro) groups showed a specific humoral response. The anti-DNA vaccine antibody titer did not rise as high as that of the protein groups; however, the observed protection indicated the efficiency of the DNA vaccine in activating the immune system.

CONCLUSION

While the chimeric DNA vaccine candidate induced a weaker humoral response, it remained effective in protecting against virulent strains of B. abortus and B. melitensis in the challenge route.