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In vitro differentiation of rat peritoneal macrophages into mast cells: an enzymecytochemical study
Abstract:
Under special culture conditions, rat peritoneal mononuclear phagocytes have previously been shown to transform into typical mast cells, based on their histamine contents, the increase of their membrane IgE-receptors, and the development of metachromatic, electron-dense cytoplasmic granules. In the present investigation, the enzyme-cytochemical characteristics of these cells were examined prior to and during culture. The peritoneal macrophages were found to have strong paranuclear activity of nonspecific esterases and acid hydrolases, while they were negative for peroxidase and chloroacetate esterase. During culture, two main changes in enzyme activity were observed within all the cells: (1) Paranuclear activity was lost in favour of granular enzyme activity throughout the cytoplasm, and (2) chloroacetate esterase appeared in cultured cells and developed a strong granular activity. These findings are consistent with the macrophage nature of the seeded cells and their development into mast cells during culture. They give support to the theory that mast cells originate from the monocyte-macrophage lineage.
Insights
Rat macrophages transform into mast cells in culture, showing distinct enzyme activity changes. This supports the theory that mast cells originate from the monocyte-macrophage lineage.
Area of Science:
- Cell Biology
- Immunology
- Histology
Background:
- Rat peritoneal mononuclear phagocytes can differentiate into mast cells under specific culture conditions.
- Previous studies noted changes in histamine content, IgE receptors, and granule development during this transformation.
Purpose of the Study:
- To investigate the enzyme-cytochemical characteristics of rat peritoneal mononuclear phagocytes before and during their transformation into mast cells in culture.
- To elucidate the cellular mechanisms underlying mast cell differentiation from macrophages.
Main Methods:
- Enzyme-cytochemical analysis of peritoneal macrophages.
- Observation of enzyme activity changes during in vitro culture.
- Assessment of nonspecific esterases, acid hydrolases, peroxidase, and chloroacetate esterase.
Main Results:
- Peritoneal macrophages initially exhibited strong paranuclear activity of nonspecific esterases and acid hydrolases, and were negative for peroxidase and chloroacetate esterase.
- During culture, cells lost paranuclear enzyme activity, showing granular activity throughout the cytoplasm.
- Chloroacetate esterase activity emerged and became strongly granular in cultured cells.
Conclusions:
- The observed enzyme activity shifts confirm the macrophage origin of the cultured cells.
- The findings support the differentiation of macrophages into mast cells.
- This study provides evidence for the monocyte-macrophage lineage as the origin of mast cells.