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Ultrastructural changes in hamster tracheal ring cultures exposed to Mycoplasma pneumoniae
Abstract:
Ultrastructural studies of lung biopsies in this laboratory from 2 children with chronic respiratory disease and elevated titers to Mycoplasma pneumoniae showed increased pleomorphic lysosomes in alveolar macrophages. This suggested that intracellular digestion might be an important feature of mycoplasma infection and an in vitro study was undertaken. Tracheal ring cultures from 35 Syrian hamsters were exposed to Clyde M129 strain of M pneumoniae. Controls consisted of untreated tracheal rings from the same animals. Both groups were subjected to light, fluorescent, and electron microscopy. Cultures exposed to virulent mycoplasma exhibited specific immunofluorescence at mucosal surfaces and in the submucosa. Mucosal cytopathic changes and submucosal necrosis were prominent. Submucosal macrophages contained increased numbers of lysosomes, some of which contained mycoplasma-like forms. If Mycoplasma pneumoniae are ingested by macrophages, this would provide a mechanism through which immune phenomena could occur and would partially explain the prominent peribronchial lymphocytic accumulation of human mycoplasma infection.
Insights
Mycoplasma pneumoniae infection in hamsters caused lung tissue damage and increased lysosomes in macrophages. Macrophages may ingest bacteria, potentially triggering immune responses in chronic respiratory disease.
Area of Science:
- Pulmonary Pathology
- Microbiology
- Immunology
Background:
- Chronic respiratory disease in children is linked to Mycoplasma pneumoniae.
- Ultrastructural lung biopsy analysis revealed increased lysosomes in alveolar macrophages.
Purpose of the Study:
- To investigate the role of intracellular digestion in Mycoplasma pneumoniae infection.
- To examine the effects of M. pneumoniae on tracheal ring cultures in vitro.
Main Methods:
- Tracheal ring cultures from Syrian hamsters were exposed to M. pneumoniae.
- Light, fluorescent, and electron microscopy were used for analysis.
- Immunofluorescence detected M. pneumoniae in mucosal and submucosal tissues.
Main Results:
- M. pneumoniae exposure caused mucosal cytopathic changes and submucosal necrosis.
- Submucosal macrophages showed increased lysosomes containing mycoplasma-like forms.
- Specific immunofluorescence confirmed M. pneumoniae presence.
Conclusions:
- Intracellular ingestion of M. pneumoniae by macrophages is a potential mechanism for immune phenomena.
- This process may contribute to peribronchial lymphocytic accumulation observed in human infections.