Figure 3.

CD4⁺ CD25^high T cells suppress polyclonally stimulated CD4⁺ CD25⁻ and Vδ2⁺ T cells. Fluorescence-activated cell sorted CD4⁺ CD25⁻ (a) and Vδ2⁺ T cells (b) (2.5 × 10⁴ cells/well) were stimulated with plate-bound anti-CD3 monoclonal antibody (10 μg/ml) and interleukin-2 (25 U/ml) in the presence or absence of CD4⁺ CD25^high regulatory T cells (Tregs) in a 1 : 1 effector to suppressor ratio. Tregs were also stimulated without effector cells. Cell culture supernatants were harvested on day 5 and interferon-γ (IFN-γ) was determined by enzyme-linked immunosorbent assay. Shown are mean values ± SEM of three independent experiments. (c) Percentage suppression of IFN-γ production was determined as follows: (IFN-γ in cultures with CD4⁺ CD25^high)/(IFN-γ in cultures without CD4⁺ CD25^high) × 100. Means ± SEM of three independent experiments are shown.