Effect of different cytokines on the suppressive activity of the Treg clone CD4⁺CD25⁺ no. 8 on the proliferation of Th1 or Th2 cells. T-cell blasts from 8 Th1 and 9 Th2 clones were stimulated for 5 days with 10⁵ allogeneic-irradiated T-cell–depleted PBMNCs with or without 3 different concentrations of T-cell blasts (target–regulatory cell ratio 1:1, 2:1, and 4:1) from the autologous Treg clone CD4⁺CD25⁺ no.8, in the absence (medium) or the presence of rIL-2 (10 U/mL), rIL-4 (2 ng/mL), rIL-7 (1 ng/mL), rIL-9 (2 ng/mL), or rIL-15 (7 ng/mL). Results are expressed as mean values (+ SD) of percentage of inhibition of proliferation obtained in triplicate cultures of the 8 Th1 and the 9 Th2 clones. ^*P < .01.