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Inhalation of (1-->3)-beta-D-glucan causes airway eosinophilia
B Fogelmark1, J Thorn, R Rylander
1Department of Environmental Medicine, Göteborg University, Sweden.
Background:
Moulds are present in a variety of environments and aerosols of fungal spores are generated when mouldy materials are handled. Molds contain (1-->3)-beta-D-glucan, a polyglucose which is present in the cell wall of fungi, certain bacteria and plants.
Aim:
This study was undertaken to investigate the cellular inflammatory response in the lung after inhalation of (1-->3)-beta-D-glucan and bacterial endotoxin.
Methods:
Guinea pigs were exposed daily to an aerosol of pure (1-->3)-beta-D-glucan and pure endotoxin for five weeks. Lung lavage and lung interstitial cell preparations were done and the inflammatory cells counted. Histological sections were prepared from the trachea.
Results:
There was an increase in eosinophil numbers in lung lavage, lung interstitium, and the airway epithelium of animals exposed to (1-->3)-beta-D-glucan. In animals simultaneously exposed to endotoxin, there was no increase in eosinophils. In the lung interstitium, (1-->3)-beta-D-glucan exposure caused an increase in lymphocytes, which was not found after endotoxin exposure. Endotoxin exposure caused an increase in neutrophils and macrophages in lung lavage, which was not found after (1-->3)-beta-D-glucan exposure.
Conclusions:
The results support previous findings that (1-->3)-beta-D-glucan causes a different response in the airways as compared to endotoxin. Endotoxin modulated the increase in eosinophils caused by (1-->3)-beta-D-glucan exposure, suggesting a complex interaction between the microbial cell wall components.
Insights
Inhaling (1-->3)-beta-D-glucan, found in mould spores, increases eosinophils in the lungs. Bacterial endotoxin exposure alters this inflammatory response, indicating complex interactions between microbial components.
Area of Science:
- Immunology
- Environmental Health
- Respiratory Medicine
Background:
- Moulds are ubiquitous environmental contaminants.
- Fungal spores, prevalent in aerosols, contain (1-->3)-beta-D-glucan.
- (1-->3)-beta-D-glucan is a polyglucose found in fungal cell walls.
Purpose of the Study:
- To investigate the lung's cellular inflammatory response to inhaled (1-->3)-beta-D-glucan.
- To compare the inflammatory effects of (1-->3)-beta-D-glucan and bacterial endotoxin.
- To understand the interaction between these microbial cell wall components in the airways.
Main Methods:
- Guinea pigs were exposed to aerosols of (1-->3)-beta-D-glucan and endotoxin for five weeks.
- Lung lavage and interstitial cell preparations were analyzed for inflammatory cell counts.
- Histological examination of tracheal sections was performed.
Main Results:
- Exposure to (1-->3)-beta-D-glucan increased eosinophils in lung lavage, interstitium, and airway epithelium.
- Simultaneous exposure to endotoxin abolished the eosinophil increase induced by (1-->3)-beta-D-glucan.
- (1-->3)-beta-D-glucan increased lymphocytes, while endotoxin increased neutrophils and macrophages in lung lavage.
Conclusions:
- Results confirm distinct inflammatory responses to (1-->3)-beta-D-glucan and endotoxin.
- Endotoxin modulates the eosinophilic response to (1-->3)-beta-D-glucan.
- A complex interaction exists between microbial cell wall components in the respiratory system.