• Vaccine Name: live attenuated Brucella melitensis 16M delta vjbR vaccine
• Target Pathogen: Brucella spp.
• Target Disease: Brucellosis
• Vaccine Ontology ID: VO_0009457
• Type: Live attenuated vaccine
• Status: Research
• Host Species for Licensed Use: Sheep
• Host Species as Laboratory Animal Model: Ovis aries (pregnant sheep)
• Antigen: vjbR deletion mutant
• Preparation: Live attenuated Brucella melitensis 16MΔvjbR strain administered subcutaneously at 1 × 10^10 CFU/ml. (Hensel et al, 2020)
• Description: The vaccine candidate Brucella melitensis 16MΔvjbR was evaluated for safety and efficacy in pregnant sheep, a natural host species, to address the limitations of the current live-attenuated vaccine Rev. 1 which causes abortions in pregnant animals. Efficacy: 16MΔvjbR provided protection comparable to Rev. 1 with no statistical difference in colonization of target organs after challenge. Immune response: Not reported explicitly in the abstract. (Hensel et al, 2020)

Sheep Response

• Vaccination Protocol: Pregnant sheep (n=6) were vaccinated subcutaneously at approximately 70 days gestation with 16MΔvjbR or Rev. 1. (Hensel et al, 2020)
• Challenge Protocol: Efficacy was tested by conjunctival challenge with 1 × 10^7 CFU/ml B. melitensis five weeks postpartum, followed by assessment of tissue colonization. (Hensel et al, 2020)
• Efficacy: 16MΔvjbR provided protection comparable to Rev. 1 with no statistical difference in colonization of target organs after challenge. (Hensel et al, 2020)
• Description: Pregnant sheep (n=6) were vaccinated subcutaneously at approximately 70 days gestation with 16MΔvjbR or Rev. 1. Safety was assessed by abortion rates, placental colonization, and vertical transmission evaluated by culture and histopathology of fetal tissues. Efficacy was tested by conjunctival challenge with 1 × 10^7 CFU/ml B. melitensis five weeks postpartum, followed by assessment of tissue colonization. (Hensel et al, 2020)