FITC dextran and HRP uptake by the two DC subpopulations are mediated through mannose receptors. (A and B) The experiments were performed on day-6 CD1a precursors by double color fluorescence (A) and on day-11 CD14-derived DCs (B). Cells were pulsed for 15 minutes at 37°C with 0.1 mg/mL FITC dextran in the presence of medium, 10% supernatant MoAb anti-mannose receptor (anti-MR), 50% supernatant MoAb anti-MR, or 1 mg/mL mannan. (C) Cells were processed at day 6 for double staining using anti-MR shown by PE-conjugated antimouse Ig. Then, after saturation in 5% mouse serum, cells were stained with anti-CD14–FITC or anti-CD1a–FITC. A total of 20,000 events were acquired. Histograms show PE staining gated on CD1a⁺ cells (left) or on CD14⁺ cells (right). (D) CD1a- and CD14-derived DC subsets, obtained as described in Materials and Methods and in the legend to Fig 1, were processed at day 11 for single staining using anti-MR shown by PE-conjugated antimouse Ig. A total of 5,000 events were acquired. White histograms represent isotype matched control. Results of each panel are representative of three experiments or more.