Figure 3

T _reg cells are susceptible to cytokine deprivation apoptosis in vivo. (a) Frequency of CD4⁺ Foxp3⁺ (upper panels) or CD25⁺Foxp3⁺ (lower panels) in splenocytes isolated from WT, Bcl-2 tg mice ex vivo. (b) Splenocytes of WT or Bim^-/- mice showing the frequency of CD4⁺ Foxp3⁺ (upper panel) or CD25⁺Foxp3⁺ (lower panel) T_reg cells ex vivo (c) Mean percentage of T_reg cells in spleens of WT (grey bar) or Bim^-/- mice (solid black bar) (n = 3–5, n = number of mice). Data represent two independent experiments. (d) Viability of T_con or T_reg cells from WT or Bim^-/- mice stimulated for 3 days with soluble anti-CD3 and anti-CD28. Cytokines were added at indicated 20 ng/ml concentrations in cultures at the beginning of stimulation. Percentage of events in the PI^neg and FSC^high live gates are shown. Histograms of CFSE dilution of live T_resp cells (e) and level of apoptosis in T_resp cells (f) from WT mice co-cultured with T_con cells or T_reg cells from WT (upper panels) or Bim^-/- (lower panels) mice. (g) Dot plots showing Foxp3 expression and CFSE dilution in live T_resp cells co-cultured with WT (upper panels) or BIM^-/- (lower panels) T_con or T_reg cells stimulated as in 'd' for 4 days in the presence or absence of IL-7 (20 ng/ml).