The effects of CCR7 ligands on the endocytosis of FITC-dextran by immature or mature DCs. BC1 cells were incubated with FITC-dextran (Dex) at 1 mg/mL in the presence or absence of CCL19 or CCL21 for the indicated times. Unstimulated BC1 cells were used as immature DCs (iDC). BC1 cells treated with LPS for 24 hours were used as mature DCs (mDC). (A) Time course of endocytosis by immature or mature DCs; each symbol represents the mean ± SE of 3 independent experiments. (B) Time course of endocytosis by mature DCs within 5 minutes; each symbol represents the mean ± SE of 3 independent experiments. (C) Amount of FITC-Dex internalized by mature DCs at 1 minute; data are representative of 3 independent experiments.