CD8α^– DCs but not CD8α⁺ DCs cross-present intestinal OVA in MLNs. Groups of mice received intravenous (5 mg) or intragastric (100 mg) OVA, and low-density cells were prepared as described in Figure 3. (A) Isolated cells were stained with CD11c and CD8α, and cells in the boxed areas were sorted and used as CD8α⁺ DCs and CD8α^– DCs, respectively. (B-C) CD8α^–CD11c⁺ or CD8α⁺CD11c⁺ cells were sorted by FACS and cocultured with CFSE-labeled OT-1 T cells for 3 days. Then they were analyzed by flow cytometer for their division (B) or [³H] methyl thymidine incorporation (C) after an 18-hour pulse. The percentages of cells that had divided are indicated (B). CPM indicates counts per minute (C). (D-E) CD8α^–CD11c⁺ or CD8α⁺CD11c⁺ cells were sorted by FACS from the spleens or MLNs of naive C57BL/6 mice then pulsed with 500 μg/mL whole OVA for 6 hours (D) or 1 μM K^b-restricted OVA peptide for 1 hour (E). These cells were cocultured with OT-I T cells for 3 days and pulsed with [³H] methyl thymidine for 18 hours then analyzed for tritium incorporation. (C-E) Values represent the mean ± SE. Data are representative of at least 2 experiments.