Related Experiment Video
Updated: Jun 19, 2026
Characterizing Salmonella Typhimurium-induced Septic Peritonitis in Mice
Published on: July 29, 2022
MICROBIC VIRULENCE AND HOST SUSCEPTIBILITY IN PARATYPHOID-ENTERITIDIS INFECTION OF WHITE MICE : III. THE IMMUNITY OF
1Laboratories of The Rockefeller Institute for Medical Research.
Abstract:
Mice which survive a preliminary dose per os of paratyphoid-enteritidis bacilli are more resistant to a second dose per os of a similar epidemic mouse typhoid strain than are mice which have received no preliminary culture. The amount of this resistance is related to the pathogenicity of the preliminary strain more than to its antigenic similarity to the second strain. Mice which survive a preliminary dose per os of paratyphoid-enteritidis bacilli are more resistant to a lethal dose of mercury bichloride per os than are mice which have not received the preliminary bacterial culture. Mice which have resisted and mice which have recovered from a preliminary dose per os of paratyphoid-enteritidis bacilli are more resistant to a lethal intraperitoneal dose of an epidemic mouse typhoid strain than are mice which have not received the preliminary culture. Mice in which the preliminary dose of paratyphoid-enteritidis bacilli has induced a chronic infection readily succumb to a second dose of such bacilli. These findings indicate that the resistance mechanism of the host contains important non-specific factors which vary in degree with the individual mice.
Insights
Mice surviving an initial dose of paratyphoid-enteritidis bacilli show increased resistance to subsequent bacterial challenges and mercury bichloride. This resistance is linked to strain pathogenicity, not just antigen similarity, highlighting non-specific host defense factors.
Area of Science:
- Immunology
- Microbiology
- Host-Pathogen Interactions
Background:
- Understanding non-specific host resistance mechanisms is crucial for developing effective countermeasures against bacterial infections.
- Previous studies suggest that prior exposure to certain pathogens can modulate host immunity.
Purpose of the Study:
- To investigate the impact of a preliminary oral dose of Salmonella enterica serovar Typhimurium (paratyphoid-enteritidis bacilli) on the resistance of mice to subsequent challenges.
- To determine if this induced resistance is specific to the challenge strain or a more general phenomenon.
Main Methods:
- Mice were administered a preliminary oral dose of paratyphoid-enteritidis bacilli.
- Survival rates and resistance were assessed following subsequent oral or intraperitoneal challenges with homologous or heterologous bacterial strains and mercury bichloride.
- The role of strain pathogenicity and antigenic similarity was evaluated.
Main Results:
- Mice surviving the preliminary dose exhibited enhanced resistance to a second oral dose of a similar mouse typhoid strain.
- This resistance was more dependent on the pathogenicity of the preliminary strain than its antigenic similarity.
- Pre-exposed mice also showed increased resistance to lethal oral doses of mercury bichloride.
- Mice that resisted or recovered from the initial infection were more resistant to a lethal intraperitoneal challenge.
- Conversely, mice developing chronic infections succumbed readily to a second dose.
Conclusions:
- Host resistance mechanisms involve significant non-specific factors that vary individually.
- Preliminary exposure to paratyphoid-enteritidis bacilli can induce a state of enhanced, non-specific resistance in mice.
- The degree of resistance is influenced by the pathogenicity of the initial bacterial strain and the host's response, rather than solely antigenic mimicry.
