TNF-α mediates fucoidan-induced maturation of blood DCs. (A) After PBDCs (10⁶) were treated with or without fucoidan, LPS, or TNF-α for 24 hours, the supernatant of the cultures was collected, and the concentrations of cytokines were measured by ELISA. (B) iMDDCs were treated with SR-A siRNA as in Figure 3A and then incubated with or without fucoidan (50 μg/mL) or LPS (1 μg/mL). After 24 hours, TNF-α secretion was measured by ELISA. (C) PBDCs were incubated with or without 5 μg/mL anti–SR-A Ab for 1 hour, then further cultured in the presence or absence of fucoidan for 24 hours. (D) CD11c⁺ mDCs were purified from lin⁻BDCA⁺ cells using a cell sorter and treated with or without fucoidan or LPS as in Figure 2B. After 24 hours, TNF-α secretion was measured by ELISA. (E) PBDCs and iMDDCs were then pretreated with neutralizing Ab against TNF-α (1 μg) for 1 hour, then further incubated in the presence of fucoidan or TNF-α for 24 hours. The results shown represent the mean ± SD of 3 independent experiments. *P < .01; n.d. indicates not determined.