CD4⁺/CD25⁺ cells from IL-2–treated patients are not anergic.

(A) Separated CD4⁺/CD25⁺ (black bars) and CD4⁺/CD25⁻ (white bars) subsets from cells of IL-2–treated patients were stimulated with anti-CD3 with or without anti-CD28 (n = 12), PHA (n = 12), TT (n = 7), CMV (n = 10), PWM (n = 11), and IL-2 (n = 8). Geometric means (net cpm), SE bars, andP values for paired comparisons (paired Student ttest) are shown. (B) CD4⁺/CD25⁺ cells from IL-2–treated patients do not suppress TCR-mediated responses of CD4⁺/CD25⁻ cells. In 6 experiments, incremental numbers of CD4⁺/CD25⁺ cells (black solid squares) were added to a fixed number (5 × 10⁴) of CD4⁺/CD25⁻ cells to test for suppression. Addition of equal numbers of CD4⁺/CD25⁻ cells (open circles) was used as a control. Results are expressed as the percentage of the proliferative response of the CD4⁺/CD25⁻ cells cultured alone, and × signs represent the proliferative response of 5 × 10⁴CD4⁺/CD25⁺ cells cultured alone. Mean values with SE bars are shown.