• Vaccine Name: Brucella ovis Microparticle Subunit Vaccine
• Target Pathogen: Brucella spp.
• Target Disease: Brucellosis
• Vaccine Ontology ID: VO_0004146
• Type: Subunit vaccine
• Antigen: A high hydrophobic antigenic complex taken from Brucella ovis (HS) (Estevan et al., 2006).
• Adjuvant:
  • Adjuvant name:
  • VO adjuvant ID: VO_0000181
• Preparation: The antigenic extract (HS) was obtained from B. ovis REO 198 cells. The bacterial cells were cultured, suspended in distilled water, and heat-killed in flowing steam. Following centrifugation, the supernatant was dialyzed against deionized water. The dialyzed material was ultracentrifuged, and the pellet (HS) was washed in dH₂O and freeze-dried. The batch of antigen used to prepare the vaccine formulation contained 48.7 ± 5.0% protein and 41.7 ± 4.7% rough lipopolysaccharide (R-LPS). The vaccine consisted of F68–CD–MP microparticles suspended in saline. F68,CD, and MP are different excipients that were used in order to facilitate the encapsulation and conserve the bioactivity of the encapsulated antigenic complex (HS) (Estevan et al., 2006).

Mouse Response

• Host Strain: BALB/c
• Vaccination Protocol: Five groups of five female BALB/c mice, 9 weeks old, were immunized subcutaneously with one of the following treatments: (i) F68–CD–MP microparticles containing 20 μg of HS per mouse in 0.1 mL saline; (ii) free HS (20 μg/mouse); (iii) empty TROMS microparticles; (iv) 5 × 10^4 CFU/mouse of the living attenuated B. melitensis Rev1 reference vaccine strain; or (v) sterile buffered saline solution, the unvaccinated control group (Estevan et al., 2006).
• Challenge Protocol: Eight weeks after vaccination, the mice were challenged by the intraperitoneal route with 1 × 10^5 CFU of B. melitensis H38 virulent strain. Two weeks after the challenge, the animals were euthanatised by cervical dislocation. The spleens of the animals were aseptically removed, individually homogenized in BSS, properly diluted, and plated in Blood Agar Base medium for viable counts (Estevan et al., 2006).
• Efficacy: A single dose administered s.c. 8 weeks before infection produced significant protection with respect to unvaccinated control mice. Moreover, this protection was similar to that conferred by B. melitensis Rev1 reference vaccine. In contrast, no significant protection was obtained when non-encapsulated HS was given to mice (Estevan et al., 2006).