Analysis of FoxP3, IFN-γ, IL-2 and Ki-67 expression in CD4+ cells from anti-CD3 activated human PBMC. Freshly isolated PBMC on day 0 (a–c) were incubated in the absence (d–f) or presence of soluble anti-CD3 at 100 (g–i), 5 and 1000 ng/ml (data not shown). Cells were stained for CD4 and FoxP3, as well as IFN-γ (a, d, g), IL-2 (b, e, h) or Ki-67 (c, f, i). Numbers in quadrants indicate the per cent of CD4 T cells. Data are representative of three separate experiments. IFN-γ, interferon-γ; IL-2, interleukin-2; PBMC, peripheral blood mononuclear cells.