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Bordetella pertussis induces respiratory burst activity in human polymorphonuclear leukocytes
L L Steed1, E T Akporiaye, R L Friedman
1Department of Microbiology and Immunology, University of Arizona, Tucson 85724.
Abstract:
Virulent Bordetella pertussis strains survive intracellularly within human polymorphonuclear leukocytes (PMN), at least in part because of inhibition of phagosome-lysosome fusion (L. L. Steed, M. Setareh, and R. L. Friedman, J. Leukocyte Biol. 50:321-330, 1991). Further investigations were done to determine if B. pertussis also inhibited respiratory burst activity of PMN as an additional mechanism of intracellular survival. Chemiluminescence and flow cytometry assays showed that B. pertussis induced significant levels of hydrogen peroxide production. In contrast, ferricytochrome c reduction showed that B. pertussis suppressed extracellular release of superoxide. PMN intracellular reduction of nitroblue tetrazolium verified that superoxide was indeed produced intracellularly during B. pertussis phagocytosis. Therefore, B. pertussis does not inhibit production of superoxide but inhibits only its release. Thus, while phagosome-lysosome fusion is inhibited by B. pertussis, respiratory burst activity of PMN occurs at normal levels.
Insights
Virulent Bordetella pertussis inhibits phagosome-lysosome fusion in human polymorphonuclear leukocytes (PMN). However, B. pertussis does not suppress superoxide production, only its extracellular release, allowing for intracellular survival.
Area of Science:
- Immunology
- Microbiology
- Cell Biology
Background:
- Virulent Bordetella pertussis (B. pertussis) survives intracellularly within human polymorphonuclear leukocytes (PMN).
- This survival is partly attributed to B. pertussis inhibiting phagosome-lysosome fusion within PMNs.
Purpose of the Study:
- To investigate if B. pertussis also inhibits the respiratory burst activity of PMNs.
- To determine if impaired respiratory burst contributes to B. pertussis intracellular survival.
Main Methods:
- Chemiluminescence assays to measure reactive oxygen species production.
- Flow cytometry to assess PMN activity.
- Ferricytochrome c reduction assay to quantify superoxide release.
- Nitroblue tetrazolium reduction assay to verify intracellular superoxide production.
Main Results:
- B. pertussis induced significant hydrogen peroxide production in PMNs.
- Extracellular superoxide release from PMNs was suppressed by B. pertussis.
- Intracellular superoxide production during B. pertussis phagocytosis was confirmed.
Conclusions:
- B. pertussis does not inhibit superoxide production but specifically inhibits its release from PMNs.
- While phagosome-lysosome fusion is inhibited, PMN respiratory burst activity occurs at normal levels intracellularly.
- These findings suggest a complex interaction between B. pertussis and PMN innate immune responses for bacterial survival.