FITC-dextran endocytosis by AC-derived and CD34⁺AC-derived DCs. DCs obtained from ACs in the presence of GM-CSF and IL-4 without (A) or with (B) TNF-α or from CD34⁺ progenitors in the presence of GM-CSF, IL-4, TNF-α and SCF (C) were incubated for various lengths of time in medium containing 1 mg/mL of FITC-dextran and analyzed on a FACScan apparatus after extensive washings. Solid lines, background uptake at 4°C; dotted lines, 7 minutes at 37°C, broken lines, 15 minutes at 37°C; bold lines, 30 minutes at 37°C. The data are representative of four experiments.