• Vaccine Name: Modified Y. pestis with TLR4-stimulating LPS
• Target Pathogen: Yersinia pestis
• Target Disease: Plague
• Vaccine Ontology ID: VO_0000832
• Type: Live, attenuated vaccine
• Preparation: Virulent Y. pestis was modified to produce a potent TLR4-stimulating LPS (Montminy et al., 2006).
• Virulence:

Mouse Response

• Host Strain: Wild-type C57BL/6 or Rag1-/- mice (Jackson Laboratories)
• Vaccination Protocol: Mice were vaccinated with a single dose (1 x 10^3 or 1 x 10^5 CFU) of Y. pestis KIM1001-pLpxL (Montminy et al., 2006).
• Side Effects: None noted.
• Challenge Protocol: At 30–40 d post vaccination, both vaccinated and naive mice were challenged subcutaneously with virulent Y. pestis KIM1001 at doses between 1 x 10^3 CFU and 1 x 10^6 CFU or by intranasal administration, mimicking pneumonic disease, of 5 x 10^3 CFU or 5 x 10^4 CFU. Survival was monitored every 12 h during acute infection up to 21 or 28 d. For collection of organs, mice were killed by pentobarbital overdose 48 h after intravenous infection or 72 h after subcutaneous infection and spleens were homogenized in PBS to obtain bacterial titers and for cytokine analysis.
• Efficacy: All mice vaccinated with Y. pestis KIM1001-pLpxL survived, whereas all naive mice died, demonstrating that Y. pestis producing potent LPS is an effective vaccine against both bubonic and pneumonic plague (Montminy et al., 2006).