CD40 triggering upregulates CD25 specifically on CD14-derived DCs. The CD1a- (upper panels) and CD14- (lower panels) derived DC subsets were obtained as described in Materials and Methods and in the legend to Fig 1. At day 12, DC subsets were recovered and cultured over CD40-L–transfected L cells on control L cells (2 × 10⁴ LCs for 1 × 10⁵ DCs) in the presence of GM-CSF for 4 days. Then cells were processed for staining using anti-CD25–PE, anti-CD86–PE, and isotype match control. A total of 5,000 events were acquired. White histograms show phenotype over control L cells and black histograms show phenotype over CD40-L transfected L cells. Results are representative of three experiments.