• Vaccine Ontology ID: VO_0011389
• Type: DNA vaccine
• Status: Research
• ompB gene engineering:
  • Type: DNA vaccine construction
  • Detailed Gene Information: Click Here.
• Vector: pcDNA3.1/V5-His-TOPO (Díaz-Montero et al., 2001)
• Immunization Route: Intramuscular injection (i.m.)

• Vaccine Ontology ID: VO_0011388
• Type: Recombinant vector vaccine
• Status: Research
• ompA gene engineering:
  • Type: Recombinant vector construction
  • Detailed Gene Information: Click Here.
• Adjuvant:
  • VO ID: VO_0000142
• Vector: Mycobacterium vaccae (Crocquet-Valdes et al., 2001).
• Immunization Route: Subcutaneous injection

Mouse Response

• Host Strain: C3H/ HeN
• Vaccination Protocol: Animals were immunized with only two doses of DNA (100 μg of recombinant plasmid and 100 μg of pIL-12) four weeks apart given intramuscularly in the tibialis anterior muscles. All mice that received DNA immunizations were also administered two booster immunizations of 100 μg each of the homologous purified recombinant protein. Control mice received either non-recombinant vector plus β-galactosidase-His recombinant protein (negative control) or a sublethal immunizing dose of R. conorii (positive
  control) (Díaz-Montero et al., 2001).
• Challenge Protocol: Mice were challenged with 3 median lethal doses (LD50) of R. conorii. In a previous experiment, this dose was shown to kill 100% of naive mice. After challenge, animals were observed daily for morbidity and mortality (Díaz-Montero et al., 2001).
• Efficacy: R. rickettsii OmpB contain B and T lymphocyte epitopes. Immunizations with each of two fragments from OmpB (rompB1550-2738 and rompB2459-4123) conferred protection against challenge with a lethal dose of R. conorii. Protection appeared to be better achieved among the groups that received both DNA and recombinant protein immunizations, although recombinant protein immunizations alone provided some protection (Díaz-Montero et al., 2001).

Mouse Response

• Host Strain: C3H/HeN mice
• Vaccination Protocol: 6–8-week-old male C3H/HeN mice were were inoculated subcutaneously with 1×10^8 to 5×10^8 of recombinant M. vaccae transformants containing rompA3006–3960. As a negative control mice were immunized with either PBS or inoculated subcutaneously with M. vaccae/pCR7, another negative control. Booster inoculations were performed 1 month later with the same dose and route. Mice immunized with M. vaccae transformants were given two additional doses of 100 μg per mouse of recombinant rickettsial GST fusion protein OmpA755–1301 suspended in incomplete Freund’s adjuvant with a 1 month interval between the immunizations (Crocquet-Valdes et al., 2001).
• Challenge Protocol: One month after the last inoculation, all groups of mice were challenged intravenously with three LD50 of R. conorii and observed daily for 2 weeks for morbidity and mortality (Crocquet-Valdes et al., 2001).
• Efficacy: Immunization with one of the constructs of Mycobacterium vaccae expressing Rickettsia rickettsii OmpA in combination with booster immunization with the homologous recombinant protein protected a significant portion of mice from lethal challenge with the closely related bacterium, R. conorii, in mice (Crocquet-Valdes et al., 2001).
• Host Ifng (Interferon gamma) response
  • Description: Production of IFN-gamma by antigen-exposed T-lymphocytes of DNA vaccine recipients indicated that cellular immunity had been stimulated. IFN-γ levels in supernatant fluid of rickettsial antigen-stimulated splenocytes from an animal that received both DNA and protein vaccinations were 47% or more higher than the controls that were vaccinated with the vector and GST or were sham-immunized with saline. This observed difference was significant and was seen in spleen cells the day before the challenge (Crocquet-Valdes et al., 2001).
  • Detailed Gene Information: Click Here.