Figure 2.

Purification and functional characterization of CD4⁺ CD25^high Foxp3⁺ T cells. (a) Peripheral blood mononuclear cells (PBMC) were labelled with anti-CD4 and anti-CD25 monoclonal antibodies and purified by fluorescence-activated cell sorting based on the level of CD25 expression. CD25^high gate was drawn around the events with > 10² mean fluorescence on the CD25 axis. Foxp3 expression was determined by intracellular staining in the sorted populations. (b) Flow-sorted CD4⁺ CD25⁻ and CD4⁺ CD25^high T cells were stimulated with plate-bound anti-CD3 monoclonal antibody plus interleukin-2. Interferon-γ (IFN-γ) was measured by enzyme-linked immunosorbent assay in 5-day culture supernatants. One representative experiment of three is shown.