Lower susceptibility of Th2 than Th1 clones to the suppressive activity of autologous Treg clones. (A) Cytokine profile of 2 Th1 (i-ii) and 2 Th2 (iii-iv) T-cell clones used as target of Treg clones, as assessed by flow cytometry at single cell level. (B) Suppressive effect of T-cell blasts from 3 Treg clones on the proliferative response to allogeneic stimulation of T-cell blasts from the 2 Th1 and the 2 Th2 clones. Results are expressed as percentage of inhibition of proliferation obtained in triplicate cultures. (C) Suppressive effect of the Treg clone CD4⁺CD25⁺ no. 8 on the proliferation of 8 Th1 or 9 Th2 clones at different target–regulatory cell ratios. Results are expressed as mean values (+ SD) of percentage of inhibition of proliferation obtained in triplicate cultures from the 8 Th1 and the 9 Th2 clones. ^**P < .0005; ^*P < .05.