• Vaccine Name: S19 DeltavjbR::Kan live vaccine candidate
• Target Pathogen: Brucella spp.
• Target Disease: Brucellosis
• Vaccine Ontology ID: VO_0009206
• Type: Live attenuated vaccine
• Status: Research
• Host Species for Licensed Use: Cattle
• Host Species as Laboratory Animal Model: Mus musculus (BALB/c mice); Mus musculus (IRF-1(-/-) knockout mice); NOD-scid IL2rγnull mouse; Sus scrofa (pregnant gilts); Mus musculus (murine bone marrow-derived macrophages and mature osteoclasts)
• Antigen: vjbR knockout mutant | vjbR deletion mutant
• Adjuvant: vitelline protein B (nimmugenic eggshell precursor protein of Fasciola hepatica) |
• Preparation: The vaccine was delivered either encapsulated in alginate microspheres containing vitelline protein B as a sustained-release vehicle or nonencapsulated. (Arenas-Gamboa et al., 2009)
  Live attenuated Brucella abortus strain 19 with vjbR gene deletion. (Arenas-Gamboa et al, 2012)
  Single intraperitoneal dose of 1 × 10^4, 1 × 10^5, or 1 × 10^6 CFU of B. abortus S19ΔvjbR. (Khalaf et al, 2019)
  Subcutaneous administration of approximately 2.0 ± 0.508 × 10^9 CFU of S19ΔvjbR. (Zriba et al, 2019)
  Live attenuated mutant strain S19vjbR of Brucella abortus. (Khalaf et al, 2020)
• Description: A vjbR knockout mutant was generated in the Brucella abortus strain 19 vaccine to improve safety and efficacy. Efficacy: A single dose of the encapsulated mutant conferred higher levels of protection against wild-type challenge compared to the nonencapsulated vaccine. Immune response: The vaccine candidate elicited an anti-Brucella-specific immunoglobulin G response even when administered in encapsulated form. Safety: The vaccine was safer than the parental S19 strain, as indicated by the absence of splenomegaly in vaccinated mice. (Arenas-Gamboa et al., 2009)
  Developed as a safer live attenuated vaccine candidate for human and animal use with demonstrated safety and protective efficacy in multiple immunocompetent animal models. Efficacy: Vaccinated mice showed significantly reduced colonization in multiple organs and reduced pathological changes after challenge with wild-type Brucella melitensis 16M. Immune response: Protection observed despite immunocompromised status, suggesting involvement of lesser-known immune mechanisms. (Arenas-Gamboa et al, 2012)
  B. abortus S19ΔvjbR was used as a vaccine candidate to evaluate safety in the mouse model. Immune response: No significant bone changes or severe inflammatory responses were observed in mice inoculated with S19ΔvjbR. (Khalaf et al, 2019)
  Live attenuated vaccine candidate derived from S19 with vjbR deletion, investigated for safety in pregnant swine. Efficacy: Not reported (study focused on safety; efficacy to be studied in future). Immune response: Robust anti-Brucella IgG humoral response induced, but of shorter duration (4-6 weeks post-inoculation) compared to cattle or mice. (Zriba et al, 2019)
  The attenuated mutant S19vjbR is a derivative of strain S19 with vjbR gene deletion, studied as a candidate vaccine. Efficacy: The mutant S19vjbR was progressively killed inside mature osteoclasts but induced significantly larger osteoclasts with enhanced resorptive activity. Immune response: No apoptosis or stimulation of nitric oxide or lactose dehydrogenase production was observed; osteoclasts infected with S19vjbR were larger and had enhanced resorptive activity. (Khalaf et al, 2020)

Mouse Response

• Host Strain: BALB/c
• Vaccination Protocol: BALB/c mice were immunized intraperitoneally with 1 x 10^5 CFU of either encapsulated or nonencapsulated S19 DeltavjbR::Kan to evaluate immunogenicity, safety, and protective efficacy. (Arenas-Gamboa et al., 2009)
• Immune Response: The vaccine candidate elicited an anti-Brucella-specific immunoglobulin G response even when administered in encapsulated form.
  Safety: The vaccine was safer than the parental S19 strain, as indicated by the absence of splenomegaly in vaccinated mice. (Arenas-Gamboa et al., 2009)
• Efficacy: A single dose of the encapsulated mutant conferred higher levels of protection against wild-type challenge compared to the nonencapsulated vaccine. (Arenas-Gamboa et al., 2009)
• Description: BALB/c mice were immunized intraperitoneally with 1 x 10^5 CFU of either encapsulated or nonencapsulated S19 DeltavjbR::Kan to evaluate immunogenicity, safety, and protective efficacy. (Arenas-Gamboa et al., 2009)

Mouse Response

• Immune Response: Protection observed despite immunocompromised status, suggesting involvement of lesser-known immune mechanisms. (Arenas-Gamboa et al, 2012)
• Challenge Protocol: Safety and efficacy tested in immunocompromised IRF-1(-/-) knockout mice; mice inoculated with vaccine and challenged with wild-type Brucella melitensis 16M. (Arenas-Gamboa et al, 2012)
• Efficacy: Vaccinated mice showed significantly reduced colonization in multiple organs and reduced pathological changes after challenge with wild-type Brucella melitensis 16M. (Arenas-Gamboa et al, 2012)
• Description: Safety and efficacy tested in immunocompromised IRF-1(-/-) knockout mice; mice inoculated with vaccine and challenged with wild-type Brucella melitensis 16M. (Arenas-Gamboa et al, 2012)

Mouse Response

• Immune Response: No significant bone changes or severe inflammatory responses were observed in mice inoculated with S19ΔvjbR. (Khalaf et al, 2019)
• Description: Mice were monitored for 13 weeks for side effects including osteoarticular disease; histological and imaging analyses were performed. (Khalaf et al, 2019)

Pig Response

• Immune Response: Robust anti-Brucella IgG humoral response induced, but of shorter duration (4-6 weeks post-inoculation) compared to cattle or mice. (Zriba et al, 2019)
• Description: Safety study in fifteen pregnant gilts at mid-gestation divided into groups and vaccinated; assessment of abortion, stillbirths, litter size, bacterial colonization, histopathology, and humoral immune response. (Zriba et al, 2019)