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Efficacy of bp26 and bp26/omp31 B. melitensis Rev.1 deletion mutants against Brucella ovis in rams
M J Grilló1, C M Marín, M Barberán
1Instituto de Agrobiotecnología, CSIC-UPNA-Gobierno de Navarra, Carretera de Mutilva, s/n. 31192, Mutilva Baja, Navarra, Spain. mariajesus.grillo@unavarra.es
Abstract:
Brucella melitensis Rev.1 is the most effective vaccine against B. ovis infection in sheep but induces antibodies interfering with B. melitensis diagnosis. Brucella BP26 and Omp31 proteins are differential diagnostic antigens. Single or double bp26 and omp31 Rev.1 deletion mutants have been proven effective against B. melitensis in sheep. Here, the CGV26 (deleted in bp26 gene) and CGV2631 (deleted in both bp26 and omp31 genes) mutants have been tested for efficacy against B. ovis in rams. Either inoculated subcutaneously or conjunctivally, both mutants conferred significant protection against B. ovis. The protection induced by CGV26 was similar to that of Rev.1 but significantly higher than that conferred by CGV2631. In conclusion, the CGV26 mutant, in association with the adequate diagnostic strategy, could be a useful alternative to Rev.1 for sheep vaccination against B. ovis infections in those countries performing simultaneously B. melitensis and B. ovis eradication campaigns.
Insights
The CGV26 mutant vaccine offers protection against Brucella ovis infection in rams, similar to the current Brucella melitensis Rev.1 vaccine. This CGV26 mutant could be a viable alternative for sheep vaccination programs targeting both B. melitensis and B. ovis.
Area of Science:
- Veterinary immunology
- Bacterial pathogenesis
- Vaccine development
Background:
- Brucella melitensis Rev.1 vaccine is effective against B. ovis but hinders B. melitensis diagnosis.
- Brucella BP26 and Omp31 proteins are key antigens for differential diagnosis.
- Deletion mutants of B. melitensis Rev.1 lacking BP26 and/or Omp31 show efficacy against B. melitensis.
Purpose of the Study:
- To evaluate the efficacy of CGV26 (bp26 deletion mutant) and CGV2631 (bp26 and omp31 deletion mutant) against Brucella ovis infection in rams.
- To compare the protective efficacy of these mutants with the standard Rev.1 vaccine.
Main Methods:
- Rams were inoculated with CGV26 or CGV2631 mutants via subcutaneous or conjunctival routes.
- Efficacy was assessed by protection against B. ovis challenge.
- Antibody responses were monitored to evaluate diagnostic interference.
Main Results:
- Both CGV26 and CGV2631 mutants provided significant protection against B. ovis challenge.
- CGV26 induced protection levels comparable to the Rev.1 vaccine.
- CGV2631 demonstrated lower efficacy compared to CGV26 and Rev.1.
Conclusions:
- The CGV26 mutant is a promising vaccine candidate for protecting sheep against B. ovis.
- CGV26 offers an alternative to Rev.1, especially in regions conducting simultaneous B. melitensis and B. ovis eradication.
- Integration with appropriate diagnostic strategies is crucial for effective implementation.
