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Brush-border membrane alkaline phosphatase activity in mouse Peyer's patch follicle-associated enterocytes
D Brown1, D Cremaschi, P S James
1AFRC Institute of Animal Physiology and Genetics Research, Babraham, Cambridge.
Insights
Researchers identified three enterocyte types in mouse Peyer's patches using alkaline phosphatase activity. Reduced enzyme activity and Cl- conductance can mark poorly differentiated enterocytes for better identification.
Area of Science:
- Gastroenterology
- Cell Biology
- Immunology
Background:
- Peyer's patches are crucial for gut immunity.
- Follicle-associated epithelium (FAE) contains specialized cells, including M cells.
- Enterocyte differentiation in FAE is not fully understood.
Purpose of the Study:
- To characterize enterocyte populations in mouse Peyer's patch FAE.
- To identify differentiation markers for FAE enterocytes.
Main Methods:
- Quantitative cytochemistry to measure alkaline phosphatase (AP) activity.
- Direct absorbance measurements on the luminal surface of enterocytes.
- Analysis of M cells and other enterocyte populations.
Main Results:
- Three enterocyte types were identified based on AP activity.
- M cells showed negligible AP activity (6 +/- 2 units).
- Two enterocyte populations had significantly different AP activities (20 +/- 2 and 30 +/- 3 units).
- M cells constituted a minimum of 3.2 +/- 1% of FAE cells.
- Reduced AP activity and brush-border membrane Cl- conductance correlate with poorly differentiated enterocytes.
Conclusions:
- Alkaline phosphatase activity is a key differentiator for FAE enterocytes.
- Reduced AP activity and Cl- conductance can identify poorly differentiated enterocytes.
- This aids in understanding FAE cell populations and their functions.
Abstract:
1. Using a new method of quantitative cytochemistry to determine alkaline phosphatase activity, it was possible to identify M cells and distinguish two further types of enterocytes present in mouse Peyer's patch follicle-associated epithelial tissue. 2. A quantitative description of these three cell types was provided by making direct absorbance measurements of enzyme reaction product on the luminal surface of individual follicle-associated enterocytes. M cells having a negligible alkaline phosphatase activity had a mean absorbance of 6 +/- 2 arbitrary units. The other two populations of enterocytes had overlapping but significantly different mean absorbances of 20 +/- 2 and 30 +/- 3 arbitrary units. 3. M cells accounted for 3.2 +/- 1% of the total number of cells present in the apical part of the follicle-associated epithelium. This percentage is a minimum value describing an extreme example of cells having M cell-like characteristics. The remaining epithelial cells were divided equally between those having high and low alkaline phosphatase activities in their brush-border membranes. A small percentage of cells having low alkaline phosphatase activities could perform M cell functions. 4. Results obtained suggest that reduced alkaline phosphatase activity and brush-border membrane Cl- conductance can both be used as differentiation markers to identify a large population of poorly differentiated enterocytes present in mouse follicle-associated epithelial tissue.