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Macrophage responses to mouldy hay dust, Micropolyspora faeni and zymosan, activators of complement by the
Abstract:
Mouse peritoneal macrophages in culture exposed to mouldy hay dust, Micropolyspora faeni or glycopeptide or protein/glycoprotein fractions from this organism show marked biochemical changes. For comparison the interaction of cultured macrophages with zymosan has been investigated. All these agents induce the release of hydrolytic enzymes from macrophages, even in the absence of serum in the medium. The release is time- and dose-dependent and is not associated with loss of the cytoplasmic enzyme lactate dehydrogenase or any other sign of cell death. The parallelism between the capacity of these agents to activate the complement system via the alternative pathway and to induce inflammatory responses in vivo and selective lysosomal enzyme secretion from cultures of macrophages is discussed. The in vitro phenomena seen with mouldy hay dust, M. faeni, the protein/glycoprotein and the glycopeptide derived from it, may be relevant to understanding the role of mononuclear phagocytes in the disease farmer's lung and other inflammatory reactions.
Insights
Mouldy hay dust components trigger biochemical changes in macrophages, releasing enzymes without causing cell death. This suggests a link between macrophage responses and inflammatory diseases like farmer's lung.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Farmer's lung is an inflammatory disease linked to mouldy hay dust exposure.
- Mononuclear phagocytes, like macrophages, play a key role in immune responses and inflammation.
Purpose of the Study:
- To investigate the biochemical effects of mouldy hay dust and its components on mouse peritoneal macrophages in culture.
- To explore the relationship between macrophage activation, complement system activation, and inflammatory responses.
Main Methods:
- Cultured mouse peritoneal macrophages were exposed to mouldy hay dust, Micropolyspora faeni, or its fractions (glycopeptide, protein/glycoprotein).
- Zymosan was used as a comparative agent.
- Release of hydrolytic enzymes and lactate dehydrogenase was measured.
- Complement system activation via the alternative pathway was assessed.
Main Results:
- Exposure to mouldy hay dust and M. faeni components induced significant biochemical changes in macrophages.
- These agents triggered the release of hydrolytic enzymes in a time- and dose-dependent manner, independent of cell death.
- A correlation was observed between the capacity of these agents to activate the complement system and induce inflammatory responses.
Conclusions:
- The in vitro findings suggest that M. faeni components can selectively induce lysosomal enzyme secretion from macrophages.
- These phenomena may be relevant to the pathogenesis of farmer's lung and other inflammatory conditions involving mononuclear phagocytes.