Related Experiment Videos
Macrophage-mediated candidacidal activity is augmented by exposure to eosinophil peroxidase: a paradigm for
D L Lefkowitz1, J A Lincoln, K R Howard
1Department of Biological Sciences, Texas Tech University, Lubbock 79409, USA.
Abstract:
Various disease states are associated with eosinophilia and the release of eosinophil peroxidase (EPO) into the microenvironment. The present study targets the effects of low levels of EPO on macrophage (M phi) phagocytosis and intracellular killing of Candida albicans as well as M phi oxidative activity measured as the luminescence product of luminol dioxygenation. Resident murine peritoneal M phi were exposed to various concentrations of EPO. Chemiluminescence data indicate that nanomolar concentrations of EPO markedly enhanced the dioxygenation activity (respiratory burst) of M phi. In other studies, the exposure of M phi to 0.17 microM EPO for 10 min. enhanced M phi-mediated candidacidal activity 10 fold. The above data indicate that EPO enhances certain M phi functions. Also the results illustrate a previously un-recognized interaction between eosinophils and M phi and implicate yet another possible role for EPO in host defenses against disease.
Insights
Eosinophil peroxidase (EPO) enhances macrophage (M phi) functions, boosting their ability to fight Candida albicans infections. This discovery reveals a new role for EPO in host defense mechanisms.
Area of Science:
- Immunology
- Cell Biology
- Host Defense Mechanisms
Background:
- Eosinophilia and eosinophil peroxidase (EPO) release are linked to various disease states.
- The interaction between eosinophils and macrophages (M phi) in host defense is not fully understood.
Purpose of the Study:
- To investigate the effects of low-level EPO on macrophage phagocytosis and intracellular killing of Candida albicans.
- To assess the impact of EPO on macrophage oxidative activity, specifically the respiratory burst.
Main Methods:
- Resident murine peritoneal macrophages were exposed to varying concentrations of EPO.
- Chemiluminescence assays were used to measure M phi oxidative activity (luminol dioxygenation).
- M phi-mediated candidacidal activity was quantified after EPO exposure.
Main Results:
- Nanomolar concentrations of EPO significantly enhanced M phi respiratory burst activity.
- Exposure to 0.17 microM EPO for 10 minutes increased M phi-mediated candidacidal activity tenfold.
- EPO was found to enhance specific macrophage functions.
Conclusions:
- Eosinophil peroxidase enhances key macrophage functions, including phagocytosis and intracellular killing of Candida albicans.
- This study highlights a previously unrecognized interaction between eosinophils and macrophages.
- EPO may play a significant role in host defense against infections and disease.