Endocytosis of FITC-dextran by THP-1 cells and THP-1 DCs. (A) Treated DCs were incubated with FITC-dextran for 1 h at 37°C and then washed for four times. Increase shift in fluorescence intensity (x-axis) was compared with the control, the one without FITC-dextran. The result was from one representative experiment of three independent repeats. (B) The increase in fluorescence intensity was calculated when compared with that of THP-1 cells alone after normalized with the background fluorescence, which was from the parallel experiments performed for all cells at 4°C. The results represented the mean ± SD from three independent experiments. ** p < 0.01 versus that of THP-1 cells.