NO reduces the LPS-induced release of IL-12p70 without affecting DC maturation. (A-B) Intracellular expression of DC-LAMP and surface expression of CD83 and CD86 (A) and CD54 (B) in DCs matured for 24 hours with 0.3 μg/mL LPS only (bold open histograms) or plus 100 μM NOR4 (open histograms). iDCs treated for 24 hours in medium only are represented by filled histograms. Isotype controls are indicated by dotted histograms. Data shown are representative of more than 10 independent experiments for DC-LAMP, CD83, and CD86 and 3 experiments for CD54. (C) iDCs were stimulated or not (□) for 24 hours with LPS (0.3 μg/mL) in the presence () or absence (▪) of graded doses of NOR4 (25, 50, 100 μM) or the vehicle control DMSO (). Supernatants were collected and analyzed for IL-12p70 and IL-6 by ELISA. ^*P < .001 compared with control LPS-treated DCs (▪), unpaired Student t test. Data are from 1 representative experiment of 9 independent experiments performed using cells from different donors. A statistical analysis of the 9 experiments using the paired t test gave a value of P = .01, confirming that the inhibition of IL-12p70 production by NOR4 is statistically significant