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Studies on the interactions of immunostimulated macrophages and Yersinia enterocolitica O:8
E Ivanova1, I Yanchev, H Najdenski
1Institute of Microbiology, Bulgarian Academy of Sciences, Sofia. eivanova@microbio.bas.bg
Abstract:
Immunological and electron microscopy investigations of the phagocytic and killing activities of peritoneal macrophages from rats and mice against Yersinia enterocolitica serotype O:8 cells were performed. The effect of in vivo application of cytoplasmic membranes (CM) from the stable Escherichia coli WF+ L-form on macrophage activity was also studied. It was established that rat macrophages more actively phagocytosed the plasmidless pYV(-) Y. enterocolitica cells, compared to the plasmid-bearing pYV(+) Y. enterocolitica cells. The killing ability against both variants of the Y. enterocolitica strain was significantly enhanced in macrophages from CM-treated rats after 2 h, 4 h, and 24 h incubation. The CM treatment enhanced the phagocytic activity of the macrophages. The in vitro interaction of normal and immunostimulated rat macrophages with both pYV(+) and pYV(-) variants of Y. enterocolitica did not lead to any additional apoptotic and necrotic changes in macrophages compared to control macrophages, which were cultivated without Y. enterocolitica. Electron-microscopic investigation showed that mouse macrophages eliminated Y. enterocolitica pYV(+) cells in vivo after 24 h. No engulfed or digested bacterial cells were observed. Activation of cell surfaces and vacuolization of macrophage cytoplasm, both of CM-treated non-infected and infected mice, were observed. The experimental results showed that Y. enterocolitica pYV(+) cells could be eliminated by peritoneal macrophages.
Insights
Cytoplasmic membranes (CM) from Escherichia coli enhanced macrophage activity against Yersinia enterocolitica. Macrophages showed increased phagocytosis and killing of bacteria, with no added toxicity, indicating potential therapeutic benefits.
Area of Science:
- Immunology
- Microbiology
- Cell Biology
Background:
- Peritoneal macrophages play a crucial role in the immune response against bacterial infections.
- Yersinia enterocolitica is a pathogen that can cause various infections.
- Understanding macrophage-host interactions is vital for developing new therapeutic strategies.
Purpose of the Study:
- To investigate the phagocytic and killing activities of rat and mouse peritoneal macrophages against Yersinia enterocolitica serotype O:8.
- To evaluate the effect of in vivo application of cytoplasmic membranes (CM) from Escherichia coli on macrophage activity.
- To assess the impact of CM treatment on macrophage apoptosis and necrosis.
Main Methods:
- Immunological assays to measure phagocytic and killing activities of macrophages.
- Electron microscopy to visualize macrophage-bacteria interactions in vivo.
- In vitro cell culture to study macrophage responses to Y. enterocolitica and CM treatment.
Main Results:
- Rat macrophages exhibited higher phagocytosis of plasmidless Y. enterocolitica compared to plasmid-bearing strains.
- CM treatment significantly enhanced macrophage killing ability against both Y. enterocolitica variants.
- Electron microscopy revealed elimination of Y. enterocolitica by mouse macrophages in vivo, with observed cell surface activation and vacuolization in CM-treated macrophages.
Conclusions:
- In vivo application of Escherichia coli cytoplasmic membranes effectively enhances peritoneal macrophage activity against Yersinia enterocolitica.
- CM treatment boosts both phagocytic and bactericidal functions of macrophages without inducing significant cellular damage.
- These findings suggest that CM could be a potential immunomodulatory agent for combating Yersinia enterocolitica infections.