Fig. 1.

(A) Monocyte-derived dendritic cells (MoDCs) produce reactive oxygen species (ROS) after incubation with various chemicals including allergens and irritants. Immature MoDCs were incubated for 1 h with sublethal concentration of allergens, such as (a) dinitrochlorobenzene (DNCB), (b) thimerosal (Thim), (c) dinitrofluorobenzene (DNFB) and (d) trinitrobenzene sulfonic acid (TNBS); and irritants, such as (e) benzalkonium chloride (BKC) and (f) sodium dodecyl sulfate (SDS). ROS production was detected by CM-H₂DCFDA assay. (A) Filled line represents control cells without CM-H₂DCFDA staining; dotted line indicates physiologic ROS level in the cells (DCFDA staining only) without treatment; solid line indicates ATP synthase inhibitor (ASI)-treated cells as a positive control; solid thick line indicates ROS level induced by chemicals. Contact allergens DNCB, TNBS, Thim and DNFB increased ROS production 3.8-fold, 2.9-fold, 3.3-fold, and 1.5-fold, respectively, compared to the control. Irritants BKC and SDS induced ROS significantly (2.6-fold and 2.0-fold, respectively). (B) Relative increase of ROS after incubation with various chemicals including allergens and irritants. The relative increase in ROS was calculated by comparing the mean fluorescence intensity (MFI) of CM-H₂DCFDA stained-treatment groups to that of the control group. Of these, the relative increases of ROS production by DNCB, Thim, and DNFB were statistically significant (p-values were 0.031, 0.029, and 0.034, respectively). Of the irritants used, BKC and SDS induced ROS significantly (p-values were 0.028 and 0.013, respectively).