Uptake of soluble material and particles by CD1a⁻ and CD1a⁺ monocyte-derived dendritic cells. Monocyte-derived moDCs collected at day 5 of culture were incubated in the presence of fluorescein-labeled exogenous compounds and particles at 37°C, and internalization by CD1a⁻ (thin line) and CD1a⁺ cells (bold line) was measured by flow cytometry. Control samples were treated similarly at +4°C (dashed lines). (A) Pinocytosis of Lucifer yellow and (B) uptake of FITC-labeled soluble dextran were measured after 1-hour incubation at 37°C. (C) The uptake of DiI-labeled oxLDL and (D) acLDL was measured after 4 hours. (E) Internalization of FITC-labeled paraformaldehyde-fixed E coli was measured after 8 hours. (F) Phagocytosis of YG-fluorescent carboxylate-modified latex beads was measured after 8 hours. Histograms (E-F) were normalized to equal numbers of nonphagocytic CD1a⁺ and CD1a⁻ cells. Typical experiments of 3 are documented.