• Vaccine Name: Brucella abortus O-polysaccharide subunit vaccine
• Target Pathogen: Brucella spp.
• Target Disease: Brucellosis
• Vaccine Ontology ID: VO_0009064
• Type: Subunit vaccine
• Status: Research
• Host Species for Licensed Use: Pig
• Host Species as Laboratory Animal Model: Mus musculus (CD-1 outbred mice); mouse peritoneal macrophages
• Antigen: O polysaccharide | O-polysaccharide (OPS)
• Preparation: Passive administration of O polysaccharide-specific IgG2a and IgG1 monoclonal antibodies and convalescent-phase serum. (Winter et al, 1989)
  Purified O-polysaccharide at doses of 100 to 500 micrograms; administered intramuscularly or orally; one or three doses. (Lord et al, 1998)
• Description: The study investigated whether antibody alone could prevent infection with Brucella abortus by using monoclonal antibodies specific to the O polysaccharide. Efficacy: 82% of mice infected with 100 CFU of B. abortus preincubated with IgG2a MAb were free of infection up to 6 weeks; higher challenge doses reduced efficacy; IgG1 MAb and convalescent serum diminished but did not prevent infection. Immune response: Antibodies of appropriate specificity and isotype (IgG2a) were effective in opsonizing B. abortus and facilitating killing by activated macrophages; killing required activated macrophages and endotoxin presence in medium. (Winter et al, 1989)
  Purified OPS from Brucella abortus 1119-3 and Brucella suis 1330 were evaluated as vaccines in field trials in Venezuela for protection of swine against Brucella suis challenge. Efficacy: Gilts vaccinated with OPS showed no serologic reactions, no abortions (100% protection), and litter sizes of 10 to 12 pigs. Immune response: No serologic reactions detected in vaccinated gilts, indicating effective protection without detectable antibody response by the assays used. (Lord et al, 1998)

Mouse Response

• Host Strain: CD-1
• Host cell type: macrophages
• Immune Response: Antibodies of appropriate specificity and isotype (IgG2a) were effective in opsonizing B. abortus and facilitating killing by activated macrophages; killing required activated macrophages and endotoxin presence in medium. (Winter et al, 1989)
• Efficacy: 82% of mice infected with 100 CFU of B. abortus preincubated with IgG2a MAb were free of infection up to 6 weeks; higher challenge doses reduced efficacy; IgG1 MAb and convalescent serum diminished but did not prevent infection. (Winter et al, 1989)
• Description: Mice were infected with virulent Brucella abortus 2308 preincubated with graded quantities of O polysaccharide-specific monoclonal antibodies; in vitro opsonization and killing assays with mouse peritoneal macrophages were also performed. (Winter et al, 1989)

Pig Response

• Immune Response: No serologic reactions detected in vaccinated gilts, indicating effective protection without detectable antibody response by the assays used. (Lord et al, 1998)
• Challenge Protocol: Purified OPS from Brucella abortus 1119-3 and Brucella suis 1330 were evaluated as vaccines in field trials in Venezuela for protection of swine against Brucella suis challenge. (Lord et al, 1998)
• Efficacy: Gilts vaccinated with OPS showed no serologic reactions, no abortions (100% protection), and litter sizes of 10 to 12 pigs. (Lord et al, 1998)
• Description: Vaccination of gilts, mating with infected boars, followed by serologic testing, bacteriologic culture, abortion monitoring, and litter size assessment. (Lord et al, 1998)