• Vaccine Name: live attenuated Brucella abortus strain 19 delta 31K vaccine
• Target Pathogen: Brucella spp.
• Target Disease: Brucellosis
• Vaccine Ontology ID: VO_0009043
• Type: Live attenuated vaccine
• Status: Research
• Host Species for Licensed Use: Cattle
• Host Species as Laboratory Animal Model: Bos taurus (calves and heifers); Mus musculus splenic macrophage cell line CRL 2471 (I-13.35)
• Antigen: 31K deletion mutant | mglA deletion mutant
• Preparation: Live attenuated vaccine derived from strain 19 with 31K gene deletion. (Cheville et al, 1992)
  Live mutant strain S19 delta 31K (Cheville et al, 1993)
  Live attenuated isogenic ΔmglA deletion mutant strain S19A used for in vitro infection. (Jacob et al, 2016)
• Description: Genetic mutant derived from strain 19 with 31K deletion was inoculated subcutaneously in calves to study bacterial survival and immune response. Efficacy: Cleared bacteria from lymph nodes more rapidly than virulent strain 2308; less lymphoid destruction; antibody titers did not persist for 16 weeks. Immune response: Induced serum antibody titers that did not persist for 16 weeks; less lymphoid destruction compared to virulent strain; no reappearance of bacteria or increase in antibody titers after dexamethasone treatment. (Cheville et al, 1992)
  Twenty-four 10-month-old Polled Hereford heifers were inoculated subcutaneously with live cells of the mutant strain. Efficacy: All vaccinated heifers were protected; none aborted and none had Brucella abortus isolated from tissues after parturition; calves born were free of Brucella abortus. Immune response: Heifers developed antibody responses to Brucella abortus and cutaneous reactions to brucellin; antibody responses after challenge exposure indicated immunity. (Cheville et al, 1993)
  Isogenic deletion mutant of the vaccine strain S19A with mglA gene deletion used to study macrophage response. Efficacy: Not directly reported; mutant showed higher bacterial load at 24 and 48 hours post infection compared to parental strain. Immune response: Mutant induced stronger pro-inflammatory cytokine and chemokine gene expression than parental strain, including IL-1α, IL-1β, TNF-α, IL6, CXCL1, CXCL2, CXCL10, CCL2, CCL5, CCL7, CCL17, CD40, ICAM1; IFNγ stimulation further increased expression of IFN√ü1, IL12√ü, MIP1α/β, NOS2, SOD2, and FAS. (Jacob et al, 2016)

Cattle Response

• Immune Response: Induced serum antibody titers that did not persist for 16 weeks; less lymphoid destruction compared to virulent strain; no reappearance of bacteria or increase in antibody titers after dexamethasone treatment. (Cheville et al, 1992)
• Efficacy: Cleared bacteria from lymph nodes more rapidly than virulent strain 2308; less lymphoid destruction; antibody titers did not persist for 16 weeks. (Cheville et al, 1992)
• Description: Subcutaneous inoculation of calves; serial examination of sera and lymph node tissues at 2-week intervals; postinoculation dexamethasone treatment; euthanasia and tissue examination for bacterial presence. (Cheville et al, 1992)