Treg cells inhibit the maturation of anti-CD3–stimulated CD8⁺ T cells. (A) Pooled data from 14 donors showing the ratio of M/E CD8⁺ T cells before (▩), and after 48 hours of stimulation of total CD8⁺ T cells with coated anti-CD3 in the presence of CD4⁺CD25⁻ T cells (□) or Treg cells (■). (B) Left panel: M/E ratio resulting from 48 hours of stimulation of sorted M (CD27⁺CD45RA⁻) CD8⁺ T cells with coated anti-CD3 in the presence of CD4⁺CD25⁻ T cells (□) or Treg cells (■). Right panel: E/TE ratio resulting from the stimulation of sorted E (CD27⁻CD45RA⁻) CD8⁺ T cells in the same conditions. Pooled data from 4 donors are shown. (C) Pooled data from 9 donors showing the expression of CD160 before (gray symbols), and after 48 hours of stimulation of total CD8 T cells with coated anti-CD3 in the presence of CD4⁺CD25⁻ T cells (open symbols) or Treg cells (filled symbols) on gated memory (M) and effector (E) CD8⁺ T cells. The P values were calculated using a paired Student t test. The mean values are depicted with horizontal bars.