Treg cells inhibit the cytokine expression after polyclonal and antigen-specific stimulation of CD8⁺ T cells. (A) Representative dot plots of CD8⁺ T cells secreting IFN-γ and IL-2 after overnight stimulation with coated anti-CD3 (left panels) or CEF (right panels) in the presence of CD4⁺CD25⁻ T (top row) or Treg cells (bottom row). The percentage of cytokine-expressing CD8⁺ T cells is indicated. (B,C) Pooled data showing the percentage of CD8⁺ T cells secreting IFN-γ or IL-2 after overnight stimulation with anti-CD3 (n = 7 donors; B) or CEF (n = 6 donors; C) in the presence of CD4⁺CD25⁻ T cells (open symbols) or Treg cells (filled symbols). The P values were calculated using a paired Student t test. The mean values are depicted with horizontal bars.