Expression of IL-7Rα differs between T cells specific for various viruses. (A) Dot plots of 2 representative healthy persons in whom T cells with different specificities could be visualized. CD8⁺ T cells (red); virus-specific CD8⁺ T cells (black). Numbers indicate percentages within virus-specific cells in the corresponding quadrants. (B) Percentages of IL-7Rα⁺ cells within virus-specific cells measured in healthy persons with different tetramers. Horizontal lines indicate median values.