Figure 5. Gating strategy. The plots present the strategy used for identifying perforin-expressing cells as a typical example of the overall gating strategy. The left panel shows the selection of cells most likely to represent lymphocytes based on their size (x-axis) and granularity (y-axis); the middle panel shows the selection of CD4⁺ and CD8⁺ T cell populations based on the expression of the CD3 receptor (y-axis) and on the absence or presence, respectively, of the CD8 receptor (x-axis); the right panel shows the selection of the CD4⁺(CD8^-)perforin⁺ cells out of the total CD4⁺(CD8^-) cells based on the expression of perforin (x-axis) plotted against side scatter (y-axis) for improved visualization.