• Vaccine Name: B. melitensis bp26 and TF Nasal Vaccine
• Target Pathogen: Brucella spp.
• Target Disease: Brucellosis
• Vaccine Ontology ID: VO_0000411
• Type: Recombinant vector vaccine
• Antigen: Purified Brucella bp26 and trigger factor (Tf) proteins, also called Tig (Yang et al., 2007).
• Tig gene engineering:
  • Type: Recombinant protein preparation
  • Description: Recombinant bp26 and Tf were produced in Pichia pastoris and purified, and mixed with cholera toxin (CT) adjuvant(Yang et al., 2007).
  • Detailed Gene Information: Click Here.
• Adjuvant:
  • Adjuvant name:
  • VO adjuvant ID: VO_0000143
  • Description: Cholera toxin (CT) was used as the adjuvant for this vaccine (Yang et al., 2007).
• Preparation: Recombinant bp26 and Tf were produced in Pichia pastoris and purified. Each vaccine consisted of either 50 or 100 micrograms per dose of either bp26, Tf, or both combined with the CT adjuvant (Yang et al., 2007).

Mouse Response

• Host Strain: BALB/c
• Vaccination Protocol: Specific pathogen-free female BALB/c mice were i.n. immunized with bp26 (50 μg/dose), Tf (100 μg/dose), or both + CT adjuvant on days 0, 7, and 14. Five μg of CT were given on day 0, and with subsequent boosts, 2 μg/dose were given. Mice were sampled for serum and fecal titers at 3–5 weeks post-immunization, before challenge (Yang et al., 2007).
• Immune Response: Mice immunized with Tf alone showed reduced serum and mucosal Ab titers. Between 3 and 5 weeks post-primary immunization, mice given bp26 + Tf showed between 14- and 32-fold greater serum IgG anti-Tf Ab titers when compared to mice given only Tf. Fecal IgA titers were augmented between 24- and 128-fold in mice immunized with bp26 + Tf when compared to mice immunized with Tf alone. These results clearly show that co-immunization with bp26 enhances anti-Tf immunity. To determine whether immune responses evoked by bp26 and Tf are biased towards Th1-type, Th2-type, or a mixture of both, serum samples from bp26 + Tf-immunized BALB/c mice from day 35 were evaluated for IgG subclass responses. IgG1 was the predominant IgG subclass Ab induced by the nasal immunization regimen. IgG2a and IgG2b anti-Tf and anti-bp26 Abs were also observed, but these were significantly less than the induced IgG1 Ab titers (Yang et al., 2007).
• Challenge Protocol: Immunized mice were challenged i.p. with 5 × 10^4 CFU B. melitensis strain 16 M on day 28 post-primary immunization [13]. A positive vaccination control was given i.p. 1 × 10^8 CFU of B. abortus RB51 vaccine 8 weeks prior to challenge. Four weeks post-challenge, splenic CFU and splenic weights were determined (Yang et al., 2007).
• Efficacy: Mice immunized with bp26 and Tf exhibited significantly reduced B. melitensis colonization when compared to PBS-dosed control mice, the control. There was no significant difference between mice immunized with these proteins when compared to RB51-vaccinated mice. No significant differences in splenic weights were observed among any of the immunization groups. These findings show that nasal immunization with bp26 and Tf is able to reduce B. melitensis colonization, and the observed splenic inflammation may be contributed by CT immunization (Yang et al., 2007).