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Thioglycollate elicited macrophages demonstrate enhanced virus replication and depressed bacterial killing
Abstract:
Thioglycollate elicited peritoneal macrophages of Balb/c mice exhibited minimal antibacterial activity against Listeria monocytogenes but were fully permissive for the replication of ectromelia virus. By comparison, resident and LPS elicited macrophages did not exhibited depressed antibacterial activity nor did they support viral replication. The thioglycollate effects were demonstrated in macrophages cultured in vitro and also in intact Balb/c mice. Mice given thioglycollate intraperitoneally and challenged by the same route suffered overwhelming virus and bacterial infections as a result of early local proliferation within peritoneal macrophages with subsequent spread to the liver. Balb/c mice challenged intravenously with similar doses of the virus of bacterial pathogen after administration of thioglycollate by the i.p. route did not succumb to either infection. Thus the ability of thioglycollate to compromise cellular host defenses against the infectious agents appears to be site specific; i.e. restricted to the peritoneal cavity where exudate macrophages and challenge inocula first come into contact.
Insights
Thioglycollate treatment weakens mouse peritoneal macrophages, increasing susceptibility to Listeria monocytogenes and ectromelia virus infections. This immune compromise is site-specific to the peritoneal cavity.
Area of Science:
- Immunology
- Microbiology
- Virology
Background:
- Thioglycollate broth is commonly used to elicit macrophages.
- The impact of thioglycollate on macrophage function against specific pathogens is not fully understood.
Purpose of the Study:
- To investigate the effect of thioglycollate-elicited peritoneal macrophages on host defense against Listeria monocytogenes and ectromelia virus.
- To determine if the observed effects are site-specific.
Main Methods:
- Balb/c mice were treated with thioglycollate intraperitoneally.
- Peritoneal macrophages were cultured in vitro and also assessed in vivo.
- Macrophages were challenged with Listeria monocytogenes and ectromelia virus.
- Infection outcomes were compared between thioglycollate-treated and control mice.
Main Results:
- Thioglycollate-elicited macrophages showed reduced antibacterial activity and supported ectromelia virus replication.
- Resident and LPS-elicited macrophages did not exhibit these defects.
- Mice treated with thioglycollate and challenged intraperitoneally showed increased susceptibility to both infections.
- Mice challenged intravenously after thioglycollate treatment were protected.
Conclusions:
- Thioglycollate administration impairs peritoneal macrophage function, compromising host defense.
- The immunosuppressive effect of thioglycollate is localized to the peritoneal cavity.
- This site-specificity is crucial for understanding susceptibility to localized infections.