Figure 4. Treg-mediated suppression requires Ikaros activity.

A Th1 cells were transfected with a plasmid expressing IK-DN or a control vector and activated in the presence of Tregs (1:1). Percent suppression of IL-2 expression was calculated (mean + s.e.m. from four experiments, t-test, *P < 0.05).

B B6 or B6-IkDN/+ CD4⁺CD25⁻ T cells (Thy1.2⁺) were labeled with CFSE and activated with APC and soluble anti-CD3 in the presence of increasing amounts of CD4⁺CD25⁺ Treg from B6-Thy1.1⁺ mice. After 3 days, suppression of responder cell proliferation was determined by FACS, assessing the degree of inhibition of CFSE dilution (mean ± s.e.m.) from two experiments.

C CD25⁻CD4⁺ T_conv cells from WT or IK-DN B6 mice were transferred into B6-Rag1^−/− mice. Twenty days later, mice received PBS or CD25⁺ CD4⁺ Treg purified from WT donors. Recipients were weighed (mean ± s.e.m.) and observed for symptoms of diarrhea approximately every 2 days (5 mice per group. one-way ANOVA **P < 0.01).

Source data are available online for this figure.