Comparison of levels of GM1 and cholesterol in the plasma membrane of splenic T cells and T-cell lines. Splenic T cells, EL4, and T28 cell lines were stained with FITC-CTxB that binds to GM1 or with filipin (12.5 μg/mL) that binds to cholesterol and analyzed by flow cytometer. The machine setting for the fluorescence detection was the same for all the cell types to allow direct comparison of the expression levels. Open histograms show fluorescence of unstained cells and filled histograms show those of stained cells. The results are representative of 3 independent experiments.