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Localization of CD44 (P80) on the external surface of a human astrocytoma cell
N Girgrah1, C A Ackerley, M A Moscarello
1Department of Biochemistry, Hospital for Sick Children, Toronto, Ontario, Canada.
Insights
A novel brain antigen, a glycoprotein, is localized to the membrane of astrocytes and astrocytoma cells. This finding aids in understanding astrocyte cell biology and potential disease markers.
Area of Science:
- Neuroscience
- Cell Biology
- Biochemistry
Background:
- An 80 kDa glycoprotein brain antigen was previously identified using MAb 44D10.
- Initial studies indicated its association with astrocyte membranes in brain tissue.
Purpose of the Study:
- To confirm and detail the membrane localization of this astrocytic glycoprotein.
- To investigate its presence on an astrocytoma cell line.
Main Methods:
- Fluorescence microscopy was employed to visualize antigen localization.
- Electron microscopy with immunogold labeling provided high-resolution ultrastructural details.
- Astrocytoma cell lines were used as a model system.
Main Results:
- The 80 kDa glycoprotein was definitively localized to the membrane of the astrocytoma cell line.
- Immunogold labeling showed heavy concentration along cellular processes.
- Labeling was also observed on smooth cell surfaces and microvilli.
Conclusions:
- The 80 kDa glycoprotein is a cell surface marker of astrocytes and astrocytoma cells.
- Its distribution suggests a role in cell-cell interactions or membrane structure.
- This antigen may serve as a valuable target for diagnostic or therapeutic strategies.
Abstract:
A brain antigen, originally identified by a MAb 44D10, has been shown to be a glycoprotein with an Mr of 80 kDa. Cellular localization studies of sections of brain showed that the antigen was associated with the membrane of astrocytes. In the present study we demonstrate its localization to the membrane of an astrocytoma cell line by fluorescence and electron microscopic immunogold methods. Heavy labelling with immunogold was found along cellular processes. Labelling of the smooth surfaces of cells and the microvilli was also observed.
