Generation of CD25⁺Foxp3⁺ 2a T cells in CLNs and not in the spleen. (A) Expansion of 2a T cells in the spleen and CLNs of DC-tg Rag2-deficient (DC-tg) or Rag2-deficient (ntg) mice at the indicated time points after transfer. The percentage of divided cells is shown. One representative experiment of 6 is shown. (B) Flow cytometry of CD25 and Foxp3 expression on 2a T cells before transfer. (C) Kinetics of 2a T-cell expansion in spleen, CLNs, and blood of DC-tg Rag2-deficient (DC-tg) or Rag2-deficient control mice (ntg) at the indicated time points after transfer. Bottom right panel: IFN-γ serum levels measured at the indicated days after transfer in DC-tg Rag2-deficient (DC-tg) or Rag2-deficient control mice (ntg). (D) Top panels: kinetics of CD44 and CD25 expression by 2a T cells in spleen and CLNs of DC-tg Rag2-deficient recipient mice at the indicated time points after transfer. Top panels: CD25 and Foxp3 expression by 2a T cells (CD4⁺Vβ14⁺ cells) in CLNs and spleen 3 weeks after transfer in DC-tg Rag2-deficient mice. (C-D) Data are mean ± SEM of 3 independent experiments performed using at least 3 mice per group. **P < .01.