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This study aimed to assess the protective efficacy of a novel Brucella vaccine formulation in goats. Twenty black goats were separated into 2 groups. Group A was injected with 3.0 × 10 9 CFU (colony-forming units)/mL of a Salmonella -based delivery system harboring only vector (pMMP65). Group B was immunized with 3.0 × 10 9 CFU/mL of the vaccine, a mixture of 3 Brucella vaccine strains (using a Salmonella -based delivery system) expressing each recombinant B. abortus Omp3b, BCSP31, and SOD protein. No Salmonella delivery strain was isolated from all tested lymph nodes and parenchymal organs. Serum immunoglobulin (Ig) G titers and interferon gamma concentrations were significantly higher in group B than those in group A. After intraconjunctival challenge with virulent B. abortus strain 544, 40% of the vaccinated animals in group B were protected against B. abortus infection. The infection index and colonization of B. abortus in tested tissues was significantly lower in group B than group A. We conclude that this Brucella vaccine induces significant antigen-specific immune responses and provides effective protection against B. abortus infection in goats. Further studies are needed to enhance the protection rate of this Brucella vaccine and to discover its practical application in small ruminants., (Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.)

The efficacy of GI24-lysed Brucella abortus cells as a vaccine candidate against brucellosis in goats was evaluated on 2 groups of Korean black goats. Group A goats were immunized subcutaneously (SC) with sterile phosphate-buffered saline, whereas group B goats were immunized SC with approximately 3 × 10 9 lysed B. abortus cells. Subcutaneous immunization with the lysed cells did not cause any negative impact on the overall clinical status, such as behavior and appetite, throughout the study period. The enzyme-linked immunosorbent assay (ELISA) optical densities values for B. abortus lipopolysaccharide in serum were considerably higher in group B than those in group A. Also, the levels of the cytokines interleukin 4 (IL-4), tumor necrosis factor-alpha (TNF-α), and interferon gamma (IFN-γ) were significantly elevated in group B compared with those in group A. Following intraconjunctival challenge with B. abortus strain 544, the severity of brucellosis in terms of infection index and colonization of B. abortus in tissues was significantly lower in group B than in group A. The present study concluded that 3 of 5 goats immunized with GI24-lysed bacteria were completely protected against challenge. Future investigations are required to improve the protective efficacy offered by lysed B. abortus cells for practical applications in small ruminants.

Salmonella is an intracellular pathogen with a cellular infection mechanism similar to that of Brucella , making it a suitable choice for use in an anti- Brucella immune boost system. This study explores the efficacy of a Salmonella Typhimurium delivery-based combination vaccine for four heterologous Brucella antigens ( Brucella lumazine synthase, proline racemase subunit A, outer-membrane protein 19, and Cu/Zn superoxide dismutase) targeting brucellosis in goats. We inoculated the attenuated Salmonella delivery-based vaccine combination subcutaneously at two different inoculation levels; 5 × 10 9 colony-forming unit (CFU)/mL (Group B) and 5 × 10 10 CFU/mL (Group C) and challenged the inoculations with virulent Brucella abortus at 6 weeks post-immunization. Serum immunoglobulin G titers against individual antigens in Salmonella immunized goats (Group C) were significantly higher than those of the non-immunized goats (Group A) at 3 and 6 weeks after vaccination. Upon antigenic stimulation, interferon-γ from peripheral blood mononuclear cells was significantly elevated in Groups B and C compared to that in Group A. The immunized goats had a significantly higher level of protection as demonstrated by the low bacterial loads in most tissues from the goats challenged with B. abortus . Relative real-time polymerase chain reaction results revealed that the expression of Brucella antigens was lower in spleen, kidney, and lung of immunized goats than of non-immunized animals. Also, treatment with our combination vaccine ameliorated histopathological lesions induced by the Brucella infection. Overall, the Salmonella Typhimurium delivery-based combination vaccine was effective in delivering immunogenic Brucella proteins, making it potentially useful in protecting livestock from brucellosis.

The aim of the present study is to estimate the protective efficacy of Brucella abortus lysed cells by GI24 against brucellosis in Beagles. Group A was subcutaneously (sc) immunized with sterile phosphate-buffered saline, and group B was sc immunized with approximately 3 × 109 of the lysed cells. Brucella-LPS-specific serum IgG titers and IL-4, TNF-α and IFN-γ concentrations were investigated by enzyme linked immunosorbent assay. All dogs were intraconjunctivally challenged with B. abortus strain 544 at 6 weeks post-prime immunization. The serum IgG titers were considerably higher in group B than in group A. The levels of IL-4, TNF-α and IFN-γ in group B than in group A were significantly higher. Following challenge, no challenge strain was observed from all tissues of three dogs of group B. However, challenge strain was detected from spleen, uterus (except one Beagle) and inguinal and retropharyngeal lymph nodes of all group A Beagles. The results of this study demonstrated that sc immunization with the lysed cells induced robust antibody and cell-mediated immune responses in Beagles. The lysed cells also conferred protection against infection with B. abortus. These results suggest that sc immunization with B. abortus lysed cells by GI24 is a good vaccine candidate against brucellosis in dogs., (© FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)