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Peritoneal macrophages of pathogen-free rats but not of conventional rats secrete elastolytic activity
Abstract:
Elicited peritoneal macrophages from Sprague-Dawley rats conventionally bred and housed failed, as we have reported, to produce detectable elastolytic activity in culture. They did produce lysozyme and plasminogen activator. We now show that in contrast to these cells, macrophages from pathogen-free, barrier-sustained rats produced readily demonstrable elastolytic activity. Rats raised pathogen-free and subsequently housed conventionally for 2-4 wk appeared to lose the capacity to afford macrophages producing elastase. At the same time they acquired infections with several rat pathogens including Spironucleus muris, Kilham rat virus, sialodacryoadinitis virus, and mycoplasma pulmonis. The acquisition by the rats of one or more of these infections, conditions conducive to infection, or both factors may have suppressed their capacity to yield elastolytic activity.
Insights
Macrophages from pathogen-free rats produce elastase, unlike those from conventionally housed rats. Infections acquired after moving to conventional housing may suppress this elastolytic activity in macrophages.
Area of Science:
- Immunology
- Cell Biology
- Rat Pathobiology
Background:
- Peritoneal macrophages from conventionally housed rats lack detectable elastolytic activity.
- These macrophages do produce lysozyme and plasminogen activator.
Purpose of the Study:
- To investigate the elastolytic activity of macrophages from pathogen-free rats.
- To determine if conventional housing or infections suppress elastolytic capacity.
Main Methods:
- Eliciting peritoneal macrophages from Sprague-Dawley rats (conventionally bred vs. pathogen-free).
- Assessing elastolytic activity, lysozyme, and plasminogen activator production in cultured macrophages.
- Monitoring rat health and identifying pathogens in conventionally housed rats.
Main Results:
- Macrophages from pathogen-free rats exhibited readily demonstrable elastolytic activity.
- Rats moved from pathogen-free to conventional housing for 2-4 weeks lost this capacity.
- Infections with rat pathogens (e.g., Spironucleus muris, Kilham rat virus) were acquired by conventionally housed rats.
Conclusions:
- Pathogen-free status is crucial for macrophage elastolytic activity.
- Conventional housing and associated infections suppress elastase production in rat macrophages.
- Infections or housing conditions may inhibit the capacity of macrophages to yield elastolytic activity.