Figure 5.

Visualization of liposome-mediated uptake of OVA by BM-DCs. (a) confocal microscopy images from a single confocal plane (0·7 μm) acquired through the centre of cells stimulated for 1 hr at 37° with 5 μg/ml OVA-AlexaFluor488 (green) with or without DDA liposomes. Cells were costained with CD11c-PE (red). The control shown is unstimulated cells. In the middle image the cell indicated with the blue arrow has been magnified and the colours adjusted to reveal the presence of internalized OVA. (b) As in (a) but shown is only cells stimulated with OVA adsorbed to DDA liposomes at 37° in the presence of Cytochalasin D or cells stimulated at 4°. (c) Distribution of OVA acquisition by CD11c⁺ cells stimulated with OVA and DDA liposomes for 1 hr at 4° (black line) or at 37° in the absence (shaded light grey area) or presence of Cytochalasin D (dark grey line) as determined by flow cytometry. (d) Confocal microscopy maximum intensity projection showing vesicular distribution of OVA after 1 hr of stimulation with DDA-adsorbed OVA-fluorescein (green) in a cell subsequently allowed to adhere for another 75 min and then stained for F-actin (red). The image has been overlaid with the corresponding transmission photomicrograph. Scale bars represent 10 μm. Data are representative of two to five experiments.