J Vet Sci.  2021 Mar;22(2):e15. 10.4142/jvs.2021.22.e15.

Protective efficacy of attenuated Salmonella Typhimurium strain expressing BLS, Omp19, PrpA, or SOD of Brucella abortus in goats

• Leya M
• Kim WK
• Ochirkhuyag E
• Yu EC
• Kim YJ
• Yeo Y
• Yang MS
• Han SS
• Lee JH
• Tark D
• Hur J
• Kim B

• KMID: 2514518
• DOI: http://doi.org/10.4142/jvs.2021.22.e15

Abstract

Background
Attenuated Salmonella strain can be used as a vector to transport immunogens to the host antigen-binding sites.
Objectives
The study aimed to determine the protective efficacy of attenuated Salmonella strain expressing highly conserved Brucella immunogens in goats.
Methods
Goats were vaccinated with Salmonella vector expressing individually lipoprotein outer-membrane protein 19 (Omp19), Brucella lumazine synthase (BLS), proline racemase subunit A (PrpA), Cu/Zn superoxide dismutase (SOD) at 5 × 10 9 CFU/mL and challenge of all groups was done at 6 weeks after vaccination.
Results
Among these vaccines inoculated at 5 × 10 9 CFU/mL in 1 mL, Omp19 or SOD showed significantly higher serum immunoglobulin G titers at (2, 4, and 6) weeks post-vaccination, compared to the vector control. Interferon-γ production in response to individual antigens was significantly higher in SOD, Omp19, PrpA, and BLS individual groups, compared to that in the vector control (all p < 0.05). Brucella colonization rate at 8 weeks post-challenge showed that most vaccine-treated groups exhibited significantly increased protection by demonstrating reduced numbers of Brucella in tissues collected from vaccinated groups. Realtime polymerase chain reaction revealed that Brucella antigen expression levels were reduced in the spleen, kidney, and parotid lymph node of vaccinated goats, compared to the nonvaccinated goats. Besides, treatment with vaccine expressing individual antigens ameliorated brucellosis-related histopathological lesions.
Conclusions
These results delineated that BLS, Omp19, PrpA, and SOD proteins achieved a definite level of protection, indicating that Salmonella Typhimurium successfully delivered Brucella antigens, and that individual vaccines could differentially elicit an antigen-specific immune response.

Keyword

Brucellosis; vaccine; Salmonella; goat