Analysis of mannose-receptor–mediated endocytosis during TNF-α–induced maturation of MDDC.

Immature MDDC were cultured for 48 hours in the absence (control) or presence of TNF-α alone (TNF-α) or after pretreatment with either PD98059 (PD and TNF-α) or SB203580 (SB and TNF-α), and endocytic activity was determined by flow cytometry using fluorescein isothiocyanate–dextran. The percentage of positive cells and the MFI (in parentheses) are indicated. In all cases, endocytic activity was also measured at 4°C (left panels) to control for nonspecific fluorescence. Each experiment was done 3 times; a representative experiment is shown.