An Unusual Biphasic Death Response in Mice Infected with Attenuated Pasteurella pestis
Abstract
The classical nonpigmented (P(-)) plague vaccine strain EV76, which is unable to absorb hematin and exhibits very low virulence for the white laboratory mouse by the intraperitoneal and subcutaneous routes, has been found to be highly virulent when injected intravenously. The lethal dose response curve is biphasic, suggesting that doses in the intermediate range of 10 to the 4th power to 10 to the 6th power organisms stimulate an effective host resistance mechanism resulting in survival of most of the mice. This peculiar virulence pattern is shown also by nonpigmented variants of strains Kim-10 and M23. The negative response phase (reflected by survival of infected animals) is less pronounced in mice infected with Fraction I minus (FI(-)) organisms such as M23 (P(-)FI(-)), and Kim-10 (P(-)FI(-)), suggesting a relationship to FI. Two suggested possible stimuli of the effective host resistance are FI and endotoxin.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1970
- Accession Number
- AD0866105
Entities
People
- Earl D. Beesley
- Michael J. Surgalla