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An ultrastructural study of peritoneal mononuclear phagocytes from Corynebacterium parvum-injected mice
Abstract:
Peritoneal mononuclear phagocytes harvested from mice 24 h after i.p. injection of C. parvum displayed hypertrophy of the Golgi and smooth endoplasmic reticulum complex with attendant increase in lysosome production. The ingested bacilli were identified within phagolysosomes, within which large myelin figures accumulated. In addition to heterophagic vacuoles, autophagosomes and lipid droplets were observed. These latter two inclusions may reflect a direct or indirect cytopathic effect of C. parvum on the phagocytes.
Insights
Corynebacterium parvum infection causes significant cellular changes in mouse peritoneal phagocytes, including organelle enlargement and increased lysosome production. These alterations suggest a potential cytopathic effect of C. parvum on these immune cells.
Area of Science:
- Immunology
- Cell Biology
- Microbiology
Background:
- Peritoneal mononuclear phagocytes play a crucial role in immune responses.
- Understanding cellular responses to microbial infections is vital for developing therapeutic strategies.
- Corynebacterium parvum (C. parvum) is known to modulate the host immune system.
Purpose of the Study:
- To investigate the ultrastructural changes in peritoneal mononuclear phagocytes following C. parvum infection.
- To identify the intracellular fate of ingested C. parvum within phagocytes.
- To explore potential cytopathic effects of C. parvum on phagocyte cellular machinery.
Main Methods:
- Peritoneal mononuclear phagocytes were harvested from mice 24 hours after intraperitoneal (i.p.) injection of C. parvum.
- Transmission electron microscopy was employed to examine the ultrastructure of these phagocytes.
- Analysis focused on organelle morphology, phagolysosome contents, and other intracellular inclusions.
Main Results:
- Phagocytes exhibited hypertrophy of the Golgi apparatus and smooth endoplasmic reticulum.
- Increased lysosome production was observed, with ingested C. parvum located within phagolysosomes.
- Accumulation of large myelin figures, autophagosomes, and lipid droplets within phagocytes were noted.
Conclusions:
- C. parvum infection induces significant ultrastructural alterations in peritoneal mononuclear phagocytes.
- The presence of myelin figures, autophagosomes, and lipid droplets suggests a potential cytopathic effect of C. parvum.
- These findings provide insights into the host-pathogen interactions at the cellular level.