• Vaccine Name: live attenuated Brucella melitensis strain 16M delta vjbR vaccine
• Target Pathogen: Brucella spp.
• Target Disease: Brucellosis
• Vaccine Ontology ID: VO_0009247
• Type: Live attenuated vaccine
• Status: Research
• Host Species for Licensed Use: Goat
• Host Species as Laboratory Animal Model: Mus musculus (IRF-1(-/-) knockout mice); BALB/c mice; macrophage; guinea pig; Capra hircus; Mus musculus
• Antigen: vjbR deletion mutant | vjbR deletion mutant; VjbR protein
• Preparation: Live attenuated Brucella melitensis strain 16 M with vjbR gene deletion. (Arenas-Gamboa et al, 2012)
  A single subcutaneous dose containing 1x10^9 CFU of B. melitensis 16MΔvjbR was delivered either encapsulated in alginate microcapsules or non-encapsulated. (Castaño-Zubieta et al, 2021)
  A vjbR mutant of Brucella melitensis strain 16M was constructed by replacing the vjbR gene with a kanamycin resistance gene. (Wang et al., 2011)
  Live attenuated vaccine candidate 16MΔvjbR administered subcutaneously. (Hensel et al, 2022)
• Description: 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)
  The study investigates the safety of the Brucella melitensis 16MΔvjbR strain vaccine candidate in young goats over a 15-month period including vaccination, impregnation, delivery, and lactation. Efficacy: Not reported (the study focused on safety, not efficacy). Immune response: Blood samples were collected to assess humoral immune response throughout the study; specific immune response results are not detailed in the abstract. (Castaño-Zubieta et al, 2021)
  The vjbR gene, a quorum sensing regulator involved in Brucella intracellular survival, was targeted to develop a vaccine candidate that allows differentiation between infection and vaccination. Efficacy: Vaccination with 16MΔvjbR conferred significant protective immunity against Brucella melitensis strain 16M challenge, equivalent to the licensed vaccine Rev. 1. Immune response: The vjbR deletion mutant elicited a Brucella-specific immunoglobulin G response and induced secretion of gamma interferon and interleukin-10. (Wang et al., 2011)
  Males were vaccinated using subcutaneous injection with vaccine candidate 16MΔvjbR at 10^9 CFU/100 μl. Efficacy: Vaccination resulted in a significant reduction in colonization in the mouse reproductive organs but did not correlate with decreased inflammation; efficacy varied between species and reproductive organs. Immune response: Not reported. (Hensel et al, 2022)

Goat Response

• Immune Response: Blood samples were collected to assess humoral immune response throughout the study; specific immune response results are not detailed in the abstract. (Castaño-Zubieta et al, 2021)
• Description: Forty healthy female crossbreed goats were divided into four groups and vaccinated; controls received empty capsules or the commercial Rev. 1 vaccine. Goats were naturally bred seven months post-vaccination and carried pregnancies to term. Blood samples were collected throughout to assess humoral immune response. Necropsy and bacteriology/histology were performed two months post-delivery on dams and offspring. (Castaño-Zubieta et al, 2021)