Defective Localization of the NADPH Phagocyte Oxidase to Salmonella-Containing Phagosomes in Tumor Necrosis Factor p55 Receptor-Deficient Macrophages
Tumor necrosis factor receptor (TNFR) p55-knockout (KO) mice are susceptible profoundly to Salmonella infection. One day after peritoneal inoculation, TNFR-KO mice harbor 1,000-fold more bacteria in liver and spleen than wild-type mice despite the formation of well organized granulomas. Macrophages...
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Veröffentlicht in: | Proceedings of the National Academy of Sciences - PNAS 2001-02, Vol.98 (5), p.2561-2565 |
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Sprache: | eng |
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Zusammenfassung: | Tumor necrosis factor receptor (TNFR) p55-knockout (KO) mice are susceptible profoundly to Salmonella infection. One day after peritoneal inoculation, TNFR-KO mice harbor 1,000-fold more bacteria in liver and spleen than wild-type mice despite the formation of well organized granulomas. Macrophages from TNFR-KO mice produce abundant quantities of reactive oxygen and nitrogen species in response to Salmonella but nevertheless exhibit poor bactericidal activity. Treatment with IFN-γ enhances killing by wild-type macrophages but does not restore the killing defect of TNFR-KO cells. Bactericidal activity of macrophages can be abrogated by a deletion in the gene encoding TNFα but not by saturating concentrations of TNF-soluble receptor, suggesting that intracellular TNFα can regulate killing of Salmonella by macrophages. Peritoneal macrophages from TNFR-KO mice fail to localize NADPH oxidase-containing vesicles to Salmonella-containing vacuoles. A TNFR-KO mutation substantially restores virulence to an attenuated mutant bacterial strain lacking the type III secretory system encoded by Salmonella pathogenicity island 2 (SPI2), suggesting that TNFα and SPI2 have opposing actions on a common pathway of vesicular trafficking. TNFα-TNFRp55 signaling plays a critical role in the immediate innate immune response to an intracellular pathogen by optimizing the delivery of toxic reactive oxygen species to the phagosome. |
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ISSN: | 0027-8424 1091-6490 |
DOI: | 10.1073/pnas.041618998 |