Fig. 1.

Sensitivity of pDCs and conventional DCs to oxidative stress. (A) Effect of exposure to H₂O₂ on the viability of pDCs and conventional DCs. Cells were treated with increasing concentrations of H₂O₂ for 24 h. In control experiments, cells were pretreated with an antioxidant, N-acetylcysteine, for 1 h and then cotreated with H₂O₂. After treatments, cells were stained with 7-AAD and the proportion of 7-AAD-negative (living) cells was assessed by flow cytometry. Percentages of viable cells are displayed. Data are presented as means ± SE of three individual experiments. **P<0.01, ***P<0.001 vs untreated control cells, ^###P<0.001 vs cells pretreated with N-acetylcysteine. (B) Exposure to low-dose H₂O₂ (0.01 µM) increases intracellular ROS levels in pDCs, but not in conventional DCs. Cells were loaded with redox-sensitive H₂DCFDA and treated with H₂O₂ for 2 h. Changes in intracellular DCF fluorescence were determined by flow cytometry. Results are representative of three independent experiments. (C) Consumption of H₂O₂ in cell culture medium of pDCs and conventional DCs. Cells were treated with 0.01 µM H₂O₂ and samples were withdrawn from the supernatant every 5 min to assay H₂O₂ content. To measure H₂O₂ levels, cell-free supernatant samples were mixed with H₂DCFDA and fluorescence intensity was assessed by fluorimetry. Data are presented as means ± SE of three individual experiments. NAC, N-acetylcysteine; cDC, conventional DCs.