FIGURE 6.

S/T→A(ble)-Foxp3 exhibits enhanced suppressive function in vitro. CD4⁺25⁻ T lymphocytes transduced with wild type or S/T→A(ble) Foxp3 were used as suppressors in a standard in vitro Treg suppression assay against conventional CD4⁺25⁻ T cells labeled with CellTrace to track cell division. Suppressors and effectors were cultured with irradiated wild type APCs and soluble CD3 for 72 h. Proliferation data shown are gated on CD4⁺ lymphocytes. Percentage of suppression was calculated as described previously (16). Data are representative of two separate experiments. Error bars are S.E. for biological replicate cultures. **, p < 0.01, ***, p < 0.001.