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[Formation of endogenous pyrogen by mononuclear phagocytes]
Abstract:
Incubation of alveolar macrophages of rabbits and peritoneal macrophages of the abdominal cavity washing of albino mice does not lead to endogenous pyrogen release. Peritoneal macrophages obtained after peritoneal administration to mice of thioglycollate, glycogen or heterologous blood cells do not discharge pyrogen either during incubation without additional stimulation. Macrophages isolated after intraperitoneal administration of heterologous blood cells do not exhibit pyrogenic activity possibly because of a long period of time elapsed after phagocytosis of foreign agents. The triggering of pyrogen formation by macrophages can be effected by means of in vitro phagocytosis of corpuscular particles: staphylococci or heterologous blood cells.
Insights
Macrophages do not release pyrogen (fever-inducing substance) spontaneously. However, in vitro phagocytosis of particles like bacteria or foreign blood cells can trigger pyrogen formation in these immune cells.
Area of Science:
- Immunology
- Cell Biology
Background:
- Macrophages are key immune cells involved in host defense.
- Endogenous pyrogens play a role in fever regulation.
Purpose of the Study:
- To investigate the conditions under which macrophages release endogenous pyrogens.
- To determine if in vivo-primed macrophages exhibit spontaneous pyrogen release.
Main Methods:
- Incubation of rabbit alveolar and mouse peritoneal macrophages.
- Stimulation of macrophages with various agents in vivo and in vitro.
- Assay for endogenous pyrogen release.
Main Results:
- Unstimulated macrophages, regardless of prior in vivo exposure (except for recent heterologous blood cell administration), did not release pyrogen.
- In vitro phagocytosis of staphylococci or heterologous blood cells triggered pyrogen release from macrophages.
- A time delay after in vivo phagocytosis may reduce pyrogenic activity.
Conclusions:
- Macrophages require specific in vitro stimulation, such as phagocytosis, to release endogenous pyrogens.
- The pyrogenic potential of macrophages is dependent on the nature and timing of stimulation.