TOXICITY OF PASTEURELLA TULARENSIS KILLED BY IONIZING RADIATION
Abstract
Suspensions of approximately 2 x 10 to the 11th power viable Pasteurella tularensis per ml were killed by exposure to 1,000,000 r of gamma radiation. The irradiated suspensions, initially containing about 10 LD50 per ml for mice by intraperitoneal injection, immunized mice against challenge with fully virulent strains of P. tularensis. Toxicity and immunizing activity of the suspensions decreased significantly within a few days at 5 C. Mice were protected against the toxin by immune serum or by prior injection of endotoxin of Escherichia coli. Cortisone did not protect against the newly prepared suspension, but was effective against aged suspension. Lethal doses of newly prepared suspension for guinea pigs and rabbits were approximately 0.5 ml and 2 ml, respectively; cortisone protected rabbits but not guinea pigs against lethal challenge. Pyrogenic effects resembling those shown by endotoxin-containing suspensions were demonstrated in rabbits. An interpretation of the results is proposed, postulating two toxins, one labile and associated with the immunizing activity of the suspension, the other more stable and resembling classical endotoxin.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1968
- Accession Number
- AD0835189
Entities
People
- George G. Wright
- James D. Pulliam
- Marshall E. Landay
- Milton J. Finegold