Lack of endocytic activity in CD8α⁺ s-DCs from ICSBP^–/– mice. WT and ICSBP^–/– s-DCs were incubated for 40 minutes at 37°C with 2 mg/mL DX-FITC (A) or 0.3 mg/mL OVA-FITC (B), washed in cold PBS, and placed on a microscope slide. Cells were then stained with biotin-conjugated anti-CD8α mAb followed by labeling with streptavidin–Alexa 594. Slides were then fixed in cold acetone and analyzed by CLSM. Several cells for each labeling condition were analyzed and representative images are shown. Scale bars correspond to 5 μm. Images were observed through a 63 ×/1.40 PLApo oil-immersion objective lens.