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Expression of peroxidase activity in rat tracheal epithelial cells associated with Mycoplasma pulmonis
Abstract:
Endogenous peroxidase activity has not been localized in the tracheal mucosal epithelial cells of specific pathogen-free (SPF) rats. After natural infection with Mycoplasma pulmonis in SPF rats, peroxidase activity became localized to the endoplasmic reticulum, nuclear envelope, and Golgi apparatus of tracheal ciliated or mucous secretory cells. Some secretory cells occasionally had peroxidase-positive secretory granules. At 1 wk M. pulmonis was found to attach to these epithelial cells, which then showed positive peroxidase activity at 2 wk. Serum antibody titers against M. pulmonis were positive at 5 wk. These results suggest that virulent mycoplasma infection and interaction with the tracheal epithelial cells trigger the de novo expression of peroxidase activity, which seems to play a role in mucosal anti-microbial defense mechanisms.
Insights
Mycoplasma pulmonis infection in rats triggers new peroxidase activity in tracheal cells. This activity appears to be part of the mucosal immune defense against the bacteria.
Area of Science:
- Respiratory tract infections
- Cellular biology
- Immunology
Background:
- Endogenous peroxidase activity was previously unlocalized in specific pathogen-free rat tracheal mucosal epithelial cells.
- Mycoplasma pulmonis is a common respiratory pathogen in rats.
Purpose of the Study:
- To investigate the localization and potential role of endogenous peroxidase activity in rat tracheal epithelial cells during Mycoplasma pulmonis infection.
Main Methods:
- Specific pathogen-free rats were naturally infected with Mycoplasma pulmonis.
- Tracheal tissues were examined for peroxidase activity localization.
- Bacterial attachment and serum antibody titers were assessed over time.
Main Results:
- Peroxidase activity localized to the endoplasmic reticulum, nuclear envelope, and Golgi apparatus in tracheal ciliated and secretory cells post-infection.
- Peroxidase-positive secretory granules were observed in some cells.
- Mycoplasma pulmonis attachment was noted at 1 week, with positive peroxidase activity at 2 weeks, and positive serum antibodies by 5 weeks.
Conclusions:
- Virulent Mycoplasma pulmonis infection induces de novo expression of peroxidase activity in tracheal epithelial cells.
- This induced peroxidase activity likely contributes to mucosal anti-microbial defense mechanisms against mycoplasma.