Differential uptake of FITC dextran by CD1a- and CD14-derived DCs during maturation. Cord blood CD34⁺ HPCs were cultured in the presence of GM-CSF plus TNFα. After 5 to 6 days, cells were collected and half were processed for double staining, using anti-CD14–PE and anti-CD1a–FITC, and FACS-sorted into CD14⁺CD1a⁻. Half of the cells were processed for double staining, using anti-CD14–FITC and anti-CD1a–PE, and FACS-sorted into CD14⁻CD1a⁺. Using this procedure, the sorted populations were labeled with PE, thus, avoiding interferences with FITC dextran. Sorted cells were seeded in the presence of GM-CSF plus TNFα (1 to 2 × 10⁵ cells/mL) for 6 to 7 additional days with last medium changes being performed at day 10. At the indicated time points, cells were processed for FITC dextran uptake. Cells were incubated in medium containing 0.1 mg/mL FITC dextran at 37°C for 15 minutes, washed with cold medium, and analyzed on a FACScan. For days 4 and 6, FITC dextran uptake was performed on total populations by double color fluorescence using anti-CD1a–PE or anti-CD14–PE. The same parameters of the FACScan were used during the kinetic. Results are representative of three independent experiments.