• Vaccine Name: Divalent DNA B. abortus Vaccine pcDNA3.1-L7/L12-Omp16
• Target Pathogen: Brucella spp.
• Target Disease: Brucellosis
• Vaccine Ontology ID: VO_0000374
• Type: DNA vaccine
• Antigen: Brucella abortus L7/L12 protein and Omp16 protein were the antigens used in this vaccine. The vaccine was designated as pcDNA3.1-L7/L12-Omp16 (Luo et al., 2006b).
  divalent fusion DNA vaccine encoding both the Brucella abortus L7/L12 protein (ribosomal protein) and Omp16 protein (outer membrane lipoprotein), designated pcDNA3.1-L7/L12-Omp16.
• L7/L12 gene engineering:
  • Type: DNA vaccine construction
  • Description:
  • Detailed Gene Information: Click Here.
• omp16 gene engineering:
  • Type: DNA vaccine construction
  • Description:
  • Detailed Gene Information: Click Here.
• DNA vaccine plasmid:
  • DNA vaccine plasmid name:
  • DNA vaccine plasmid VO ID: VO_0000158
• Preparation: Full-length open reading frames of the L7/L12 gene and Omp16 gene were amplified with PCR from the genome of B. abortus strain RB51. The gene amplified with L7/L12 primers and/or the gene amplified with Omp16 primers were inserted into pcDNA3.1(+) vector (Invitrogen) (Luo et al., 2006b).

Mouse Response

• Host Strain: BALB/c
• Vaccination Protocol: Female BALB/c mice were distributed into two groups: each mouse in one group was inoculated intramuscularly with 100 μg of pcDNA3.1-L7/L12-Omp16, pcDNA3.1-L7/L12, or pcDNA3.1-Omp16 in 100 μl of PBS. A control group was also used in this group, and these mice were infected with PBS or the pcDNA3.1 expression vector alone. Each mouse in the other group was injected with 10 μg of rL7/L12-Omp16 in 100 μl PBS according to the same schedule. Every mouse in this group was injected on weeks 0, 2, and 4. The mice used as positive controls were inoculated intraperitoneally on day 0 with 2× 10^8 CFU of B. abortus strain RB51 in 0.2 ml of PBS (Luo et al., 2006b).
• Immune Response: The results showed that the total IgG titer of the hyperimmune sera from mice immunized with pcDNA3.1-L7/L12-Omp16, pcDNA3.1-L7/L12, or pcDNA3.1-Omp16 reached 1:1,000, 1:800, or 1:600, respectively. Immunization with rL7/L12 and live RB51 strain elicited much higher humoral immune responses in mice, with IgG titers reaching 1:25,600 and 1:50,000, respectively. The analysis of IgG subtypes showed a significant increase in IgG1 and IgG2a from the DNA vaccine group, fusion protein vaccine group, and live RB51 group compared with the pcDNA3.1 vector control (Luo et al., 2006b).
• Challenge Protocol: Five mice from each group were challenged intraperitoneally 14 days after initial immunization. These mice were given a higher dose of strain 544, 5 × 10^5 CFU (Luo et al., 2006b).
• Efficacy: Immunization with any type of DNA vaccine resulted in a significantly higher degree of protection than the controls that received only PBS. Within the three recombinant DNA vaccines, the divalent DNA vaccine provided a higher protection level than either of the univalent DNA vaccines. Immunization with the recombinant fusion protein rL7/L12 also created significant protection. This protective effect was significantly lower than that created by theimmunization with the DNA vaccines (Luo et al., 2006b).