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Cell wall preparations from environmental yeasts: effect on alveolar macrophage function in vitro
W G Sorenson1, T A Shahan, J Simpson
1Division of Respiratory Disease Studies, National Institute for Occupational Safety and Health, NIOSH/DRDS, 1095 Willowdale Road, Morgantown, WV 26505, USA. WGS1@CDC.GOV
Abstract:
Organic dust toxic syndrome (ODTS) is associated with inhalation of high concentrations of organic materials and is a noninfectious illness characterized by fever, malaise, myalgia, and neutrophilic inflammation of the lower respiratory tract. Studies in our laboratory of fungi in fresh lumber have demonstrated that yeasts may predominate and have raised the issue of potential exposure of sawmill workers to yeasts. Zymosan, a cell wall preparation from Saccharomyces cerevisiae, is a potent stimulator of alveolar macrophages (AM). In the present study, preparations from the cell walls of Pichia fabianii, Candida sake, Trichosporon capitatum, Rhodotorula glutinis, and Cryptococcus laurentii were compared with zymosan and beta-1,3-glucan for their ability to stimulate AM and activate complement. All species activated complement. P. fabianii, C. sake, T. capitatum, R. glutinis, C. laurentii, as well as zymosan and glucan, stimulated superoxide anion and leukotriene B4 production in a dose-dependent fashion, but R. glutinis and C. laurentii were much less active. Zymosan, glucan, P. fabianii, and R. glutinis treatment of AM resulted in increased phagocytosis of labeled sheep RBCs, whereas there was no effect with C. sake or C. laurentii and T. capitatum significantly inhibiting phagocytosis. These results suggest that exposure to high concentrations of yeast could provoke pulmonary inflammation resulting in an episode of ODTS.
Insights
Exposure to high concentrations of yeast, like those found in lumber, may cause organic dust toxic syndrome (ODTS). This noninfectious illness involves lung inflammation and flu-like symptoms, potentially triggered by yeast cell walls stimulating immune responses.
Area of Science:
- Immunology
- Occupational Health
- Mycology
Background:
- Organic dust toxic syndrome (ODTS) is an occupational illness linked to inhaling organic dusts.
- Sawmill workers may be exposed to yeasts from fresh lumber, which are potent immune stimulators.
- Alveolar macrophages (AM) are key immune cells in the lungs affected by inhaled particles.
Purpose of the Study:
- To investigate the immunomodulatory effects of various yeast cell wall preparations.
- To compare the ability of different yeast species to stimulate AM and activate complement.
- To determine if yeast exposure could be a trigger for ODTS.
Main Methods:
- Yeast cell wall preparations from Pichia fabianii, Candida sake, Trichosporon capitatum, Rhodotorula glutinis, and Cryptococcus laurentii were tested.
- Preparations were compared to zymosan and beta-1,3-glucan for their effects on AM and complement activation.
- Assays included superoxide anion production, leukotriene B4 release, and phagocytosis of red blood cells.
Main Results:
- All tested yeast species activated complement.
- Most yeasts, zymosan, and glucan stimulated superoxide anion and leukotriene B4 production in a dose-dependent manner.
- Yeast exposure differentially affected phagocytosis, with some enhancing it and others inhibiting it.
Conclusions:
- Exposure to high concentrations of certain yeasts could trigger pulmonary inflammation consistent with ODTS.
- Yeast cell walls possess components that activate immune cells and complement pathways.
- Further research is warranted to understand the specific role of yeasts in occupational lung diseases like ODTS.