Brucella abortus lysed cells using GI24 induce robust immune response and provide effective protection in Beagles

Abstract

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.

The emergence of Brucella canis as a public health threat in Europe: what we know and what we need to learn

“…No vaccines are commercially available for B. canis and antimicrobial treatment of infected animals, when applied, is seen as an alternative to removal of animals and usually combined with animal sterilization. Cross-protection with other anti- Brucella vaccines, used for cattle and small ruminants, has been reported, but not considered practical, since it presents a risk of vaccine strain shedding in a domestic environment with current live vaccines retaining a degree of virulence for humans [ 73 , 74 ]. The treatment of infected dogs is a debated issue as antimicrobial therapy does not guarantee B. canis elimination, with relapses of infection frequently reported in addition to the risks related to the development of antimicrobial resistance [ 53 , 75 ].…”

Brucella ovis mutant in ABC transporter protects against Brucella canis infection in mice and it is safe for dogs

“…Recent studies aiming the development of vaccine against B. canis are mostly based on protein vaccine formulations, which tend to have limited protection in mice or in the natural hosts [55][56][57][58]. Other strategies for vaccine development against B. canis infection include lysed B. abortus [59] and B. canis non-living cells envelop lacking cytoplasmic contents [60]. Considering the potential limitations of these strategies, the use of B. ovis, which has a naturally low virulence potential for dogs and man is a promising approach for the development of an efficacious and safe vaccine formulation to prevent canine brucellosis.…”

Evaluation of Brucellosis Vaccines: A Comprehensive Review

“…Another approach to vaccine development against Brucella infection includes lysed B . abortus ( 168 , 169 ) or whole organism of Brucella spp. without cytoplasmic contents.…”

“…In another study, subcutaneous co-administration of Brucella Cu-Zn SOD recombinant protein with recombinant IL-18, encapsulated in E. coli lipid liposome (escheriosome), demonstrated a stronger IgG2a-type antibody response in immunized mice compared with free BaSOD DNA. Another approach to vaccine development against Brucella infection includes lysed B. abortus (168,169) or whole organism of Brucella spp. without cytoplasmic contents.…”