CD4⁺CD25⁺ cells suppress the responses of CD4⁺CD25⁻ cells in coculture.

(A-B) CD4⁺CD25⁻ cells (▪) or CD4⁺CD25⁺ (■) (1 × 10⁴cells/well) or coculture of both CD4⁺CD25⁺ and CD4⁺CD25⁻ cells (▨) (total 2 × 10⁴ cells/well) were stimulated in the presence of irradiated autologous ACs (1 × 10⁴ cells/well) with PHA (2 μg/mL, A) in the absence or presence of IL-2 (10 U/mL); soluble anti-CD3 for 3 days (B). Proliferation was measured by³H-thymidine incorporation.(C,D) Production of IL-2 (C) and IFN-γ (D) in coculture of CD4⁺CD25⁻(1 × 10⁴) and CD4⁺CD25⁻ cells (░) or CD4⁺CD25⁺ (1 × 10⁴) cells (▨) in response to PHA (2 μg/mL) in the presence of autologous ACs (2 × 10⁴) for 72 hours. (E) The proliferative responses of CD4⁺CD25⁻ cells (1 × 10⁴) to PHA (2 μg/mL) and autologous ACs (2 × 10⁴) in the presence of various numbers of CD4⁺CD25⁺ cells.