• Vaccine Name: live attenuated Brucella abortus strain 19 delta per vaccine
• Target Pathogen: Brucella spp.
• Target Disease: Brucellosis
• Vaccine Ontology ID: VO_0009324
• Type: Live attenuated vaccine
• Status: Research
• Host Species for Licensed Use: Cattle
• Host Species as Laboratory Animal Model: Mus musculus; guinea pig; buffalo calves
• Antigen: perosamine synthetase gene deletion | perosamine synthetase gene mutant (S19Δper) | wbkB gene deletion (perosamine synthetase mutant)
• Preparation: Live attenuated S19Δper mutant with intermediate rough lipopolysaccharide phenotype. (Lalsiamthara et al, 2015)
  Live attenuated mutant strain of Brucella abortus S19 with deletion in perosamine synthetase gene. (Solanki et al, 2020)
  Administered at normal dose (4 × 10^10 CFU/animal) and reduced dose (2 × 10^9 CFU/animal) in buffaloes; bacterial persistence assessed in buffalo calves 42 days post inoculation. (Chaudhuri et al, 2021)
• Description: A modified Brucella abortus strain 19 mutant (S19Δper) with intermediate rough phenotype and residual O-polysaccharide was developed by deletion of the perosamine synthetase gene to reduce residual virulence and enable DIVA capability. Efficacy: S19Δper conferred protection in mice similar to the parental S19 vaccine strain. Immune response: Immunized mice produced strong immune responses with higher levels of IFN-γ and IgG2a, indicating a Th1 cell mediated immunity bias; sera did not agglutinate with RBPT antigen, supporting DIVA capability. S19Δper showed increased susceptibility to serum complement and polymyxin B. (Lalsiamthara et al, 2015)
  A live Brucella abortus S19 perosamine synthetase gene mutant (S19Δper) was used to explore immunological potential in mice. Efficacy: Not directly reported; transcriptome data showed activation of immune pathways suggesting immunogenic potential. Immune response: Activation of MHC-I and MHC-II antigen-processing pathways; regulation of NF-kappa B signalling, chemokine signalling, T-cell receptor pathway, apoptosis, TNF signalling, and nucleotide-binding oligomerization domain-like receptor signalling pathways indicating a robust immune response. (Solanki et al, 2020)
  Brucella abortus S19Δper is a perosamine synthetase wbkB gene deletion mutant derived from strain 19, developed to overcome safety and serodiagnostic interference drawbacks of the conventional S19 vaccine. Efficacy: All immunized buffaloes were protected against challenge with virulent B. abortus S544; lower bacterial burden in lymph nodes and absence of gross lesions observed in vaccinated animals. Immune response: S19Δper immunized animals showed significantly low anti-lipopolysaccharide antibody levels; sera exhibited moderate to weak agglutination to RBPT antigen allowing differentiation from S19 vaccinated and clinically infected animals; S19Δper was more sensitive to complement-mediated lysis than parent strain S19. (Chaudhuri et al, 2021)

Mouse Response

• Immune Response: Activation of MHC-I and MHC-II antigen-processing pathways; regulation of NF-kappa B signalling, chemokine signalling, T-cell receptor pathway, apoptosis, TNF signalling, and nucleotide-binding oligomerization domain-like receptor signalling pathways indicating a robust immune response. (Solanki et al, 2020)
• Efficacy: Not directly reported; transcriptome data showed activation of immune pathways suggesting immunogenic potential. (Solanki et al, 2020)
• Description: RNA-seq transcriptome analysis of mouse spleen at 15 days post-immunization comparing PBS control and S19∆per immunized mice. (Solanki et al, 2020)