• Vaccine Name: live attenuated Brucella melitensis strain B115 vaccine
• Target Pathogen: Brucella spp.
• Target Disease: Brucellosis
• Vaccine Ontology ID: VO_0009201
• Type: Live attenuated vaccine
• Status: Research
• Host Species for Licensed Use: Sheep
• Host Species as Laboratory Animal Model: Mus musculus
• Antigen: antigens other than O-PS
• Preparation: Live, attenuated rough strain B115 with O-PS present intracellularly but not exposed on surface. (Adone et al, 2008)
  Live attenuated rough strain B115 administered at doses of 10^8 or 10^9 CFU per mouse. (Adone et al, 2011)
  Live rough strain B115 of Brucella melitensis. (Adone et al, 2012)
• Description: Brucella melitensis strain Rev. 1 is used as vaccine for prophylaxis in sheep and goats but induces antibodies to O-polysaccharide (O-PS) complicating differentiation of vaccinated and infected animals; B115 is a natural, attenuated, rough strain lacking surface O-PS and proposed as alternative vaccine. Efficacy: Vaccination with B115 conferred significant protective immunity against B. melitensis 16M and B. ovis, equivalent to that of Rev. 1 vaccine. Immune response: No interfering antibodies to O-PS detected; vaccination monitored by specific B115-based complement fixation test. (Adone et al, 2008)
  B. melitensis strain B115 is a natural, attenuated rough strain previously shown to be highly protective against B. melitensis and B. ovis infections in mice without inducing interfering antibodies. This study tested its efficacy against B. abortus and B. suis. Efficacy: Vaccination with 10^8 CFU/mouse of B115 conferred satisfactory protection against B. abortus 2308. Single vaccination with 10^8 or 10^9 CFU/mouse provided weak protection against B. suis, but two vaccinations with 10^9 CFU/mouse significantly increased protection. Immune response: B115 showed adequate persistence in mice and induced solid humoral and cell-mediated immunity despite its rough phenotype. (Adone et al, 2011)
  The rough strain Brucella melitensis B115 was shown to protect mice against wild Brucella strains despite lacking anti-O-PS antibodies. Efficacy: Antibodies induced by B115 conferred satisfactory protection, especially against B. abortus 2308, similar to protection conferred by S19 antiserum; RB51 antiserum was ineffective. Immune response: Antibodies induced by B115 act as opsonins targeting antigens other than O-PS, promoting efficient internalization and degradation of bacteria within phagocytes. (Adone et al, 2012)

Mouse Response

• Immune Response: No interfering antibodies to O-PS detected; vaccination monitored by specific B115-based complement fixation test. (Adone et al, 2008)
• Challenge Protocol: Protective activity tested in mice against B. melitensis 16M and B. ovis challenge strains; residual virulence and humoral response evaluated. (Adone et al, 2008)
• Efficacy: Vaccination with B115 conferred significant protective immunity against B. melitensis 16M and B. ovis, equivalent to that of Rev. 1 vaccine. (Adone et al, 2008)
• Description: Protective activity tested in mice against B. melitensis 16M and B. ovis challenge strains; residual virulence and humoral response evaluated. (Adone et al, 2008)

Mouse Response

• Vaccination Protocol: Mice were vaccinated once or twice with B115 at different doses. (Adone et al, 2011)
• Immune Response: B115 showed adequate persistence in mice and induced solid humoral and cell-mediated immunity despite its rough phenotype. (Adone et al, 2011)
• Challenge Protocol: Mice were vaccinated once or twice with B115 at different doses and then challenged with B. abortus 2308 or B. suis to assess protection. (Adone et al, 2011)
• Efficacy: Vaccination with 10^8 CFU/mouse of B115 conferred satisfactory protection against B. abortus 2308. Single vaccination with 10^8 or 10^9 CFU/mouse provided weak protection against B. suis, but two vaccinations with 10^9 CFU/mouse significantly increased protection. (Adone et al, 2011)
• Description: Mice were vaccinated once or twice with B115 at different doses and then challenged with B. abortus 2308 or B. suis to assess protection. (Adone et al, 2011)

Mouse Response

• Immune Response: Antibodies induced by B115 act as opsonins targeting antigens other than O-PS, promoting efficient internalization and degradation of bacteria within phagocytes. (Adone et al, 2012)
• Efficacy: Antibodies induced by B115 conferred satisfactory protection, especially against B. abortus 2308, similar to protection conferred by S19 antiserum; RB51 antiserum was ineffective. (Adone et al, 2012)
• Description: Passive transfer of specific antisera from mice vaccinated with B. melitensis B115 to untreated mice prior to infection with virulent Brucella abortus 2308 and B. melitensis 16M strains; comparison with antisera from B. abortus RB51 and S19 vaccinated mice. (Adone et al, 2012)