Regulatory function of CD4⁺CD25⁺ Foxp3⁺ T_R cells generated in vivo by antigenic peptide-pulsed DC_regs.Rag2^−/−KJ1–26⁺ T cells were adoptively transferred with OVA_323-339 peptide/DC_regs into BALB/c mice. After 8 days, KJ1–26⁺CD25⁻ T cells and KJ1–26⁺CD25⁺ T cells were isolated from the recipient mice. Subsequently, Rag2^−/−KJ1–26⁺ T cells, KJ1–26⁺CD25⁻ T cells, or KJ1–26⁺CD25⁺ T cells (5 × 10⁴) obtained from Rag2^+/+DO11.10 BALB/c mice and the mice that received adoptive transfers were cultured with the irradiated syngeneic APCs (5 × 10⁴) in the presence of anti-CD3 mAb (10 μg/mL) (A) or OVA_323-339 peptide (1 μM) (B) for 3 days, and the proliferative response was measured. In another experiment, Rag2^−/−KJ1–26⁺ T cells (5 × 10⁴) were cultured with the irradiated syngeneic APCs (5 × 10⁴) in combination with anti-CD3 mAb (10 μg/mL) (A) or OVA_323-339 peptide (1 μM) (B) in the presence or absence of KJ1–26⁺CD25⁻ T cells and KJ1–26⁺CD25⁺ T cells (5 × 10⁴) for 3 days, and the proliferative response was measured. The error bars indicate SD. *P < .01 compared with Rag2^−/−KJ1–26⁺ T cells by Student paired t test. Results of 3 replicated experiments were pooled.