Induction and recruitment of autologous regulatory T cells by DC. (Left panel) CD4⁺CD25^neg T cells were isolated via magnetic bead-based techniques and stimulated once with autologous DCs (at a ratio of 1:10), which were matured for 24 hours as indicated. After 10 days, cells were harvested and CD4, CD25, and FoxP3 expression was analyzed by flow cytometry. For detection of intracellular FoxP3, cells were permeabilized with 0.1% saponin. (Right panel) Secretion of CCL-22 by immature DCs and DCs that were matured as indicated was determined after 24 hours by ELISA. Supernatant equivalent to CCL-22 produced by 10⁵ DCs was used to determine chemotaxis of isolated CD4⁺CD25⁺ T cells over 3 hours in transwell assays (3 μm pore size).