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Some biochemical and functional characteristics of macrophages activated by Tetrahymena pyriformis
Abstract:
Phagocytosis, enzyme activities and capacity to release hydrogen peroxide (H2O2) and superoxide anion (O2-) of peritoneal macrophages from mice inoculated with Tetrahymena pyriformis, a free-living ciliate, were examined in comparison with resident and BCG-activated macrophages. Fc receptor-mediated phagocytosis of sheep erythrocytes was markedly increased in Tetrahymena-activated macrophages to the same level as that seen in BCG-activated ones. Tetrahymena-activated macrophages showed an increased level of acid phosphatase (lysosomal enzyme) and a reduced level of alkaline phosphodiesterase I (plasma membrane ectoenzyme) as compared with resident macrophages. Similar changes in the activities of the two enzymes were also observed in BCG-activated macrophages. Both Tetrahymena- and BCG-activated macrophages exhibited more enhanced capacity to release H2O2 and O2- than resident macrophages when stimulated with phorbol myristate acetate. In the macrophages from mice inoculated with varying doses of Tetrahymena, a significant correlation was observed between the increased capacity of H2O2 and O2- release as observed in the present study, and the enhanced toxoplasmacidal activity as observed in a previous study, in a dose-dependent fashion.
Insights
Tetrahymena pyriformis activates mouse macrophages, enhancing their phagocytosis and release of hydrogen peroxide (H2O2) and superoxide anion (O2-). This immune response mirrors BCG activation, suggesting Tetrahymena as a potential immunomodulator.
Area of Science:
- Immunology
- Cell Biology
- Parasitology
Background:
- Peritoneal macrophages play a crucial role in innate immunity.
- Activation of macrophages enhances their microbicidal functions.
- Tetrahymena pyriformis is a free-living ciliate with potential immunomodulatory properties.
Purpose of the Study:
- To investigate the effects of Tetrahymena pyriformis inoculation on mouse peritoneal macrophage functions.
- To compare Tetrahymena-activated macrophages with resident and BCG-activated macrophages.
- To assess phagocytosis, enzyme activities, and reactive oxygen species production.
Main Methods:
- Peritoneal macrophages were isolated from mice inoculated with Tetrahymena pyriformis.
- Phagocytosis of sheep erythrocytes via Fc receptors was measured.
- Activities of acid phosphatase and alkaline phosphodiesterase I were assayed.
- Hydrogen peroxide (H2O2) and superoxide anion (O2-) release were quantified after stimulation.
Main Results:
- Tetrahymena-activated macrophages exhibited significantly increased Fc receptor-mediated phagocytosis, comparable to BCG-activated macrophages.
- Lysosomal enzyme (acid phosphatase) activity increased, while plasma membrane ectoenzyme (alkaline phosphodiesterase I) activity decreased in Tetrahymena-activated macrophages.
- Both Tetrahymena- and BCG-activated macrophages showed enhanced release of H2O2 and O2- upon stimulation.
- A dose-dependent correlation was found between enhanced reactive oxygen species release and previously observed toxoplasmacidal activity.
Conclusions:
- Tetrahymena pyriformis effectively activates peritoneal macrophages, enhancing their phagocytic capacity and microbicidal functions.
- The observed changes in enzyme activities and reactive oxygen species production are similar to those induced by BCG activation.
- Tetrahymena pyriformis demonstrates potential as an immunomodulatory agent, influencing macrophage responses in a dose-dependent manner.