Fig. 2. Temperature dependence of Lck, CD3 and TfR distribution. Jurkat T cells were fixed at the indicated temperatures and stained with anti-Lck, anti-CD3 or anti-TfR followed by FITC-conjugated secondary antibodies. (A) Single confocal equatorial sections show fluorescence in the fluorescein channel. Arrowheads indicate plasma membrane regions with very low fluorescence intensities in cells with a patchy distribution of fluorophore. Images are typical for the respective populations. Scale bars: 5 µm. (B) Perimeter traces of the cells shown in A. The plasma membrane was manually marked with sequential points and adjacent points were then joined by line segments to delineate the membrane. The fluorescence intensities around the membrane were copied into a one dimensional image. The x and y axes show the intensity range and total intensity, respectively. (C) Accumulative intensity distribution histograms for populations of cells; n=10/11.