NO enhances LPS-induced expression of CXCR4 and migration toward CXCL12/SDF-1α. iDCs were treated or not for 24 hours with 0.3 μg/mL LPS in the absence or presence of graded doses of NOR4. (A) Surface expression of CXCR4 or CCR7. The mean fluorescence intensity (M) and percentages of positive cells (%) are indicated. (B) Cells treated with medium only (•) or 0.3 μg/mL LPS plus graded doses of NOR4 (▴) were tested for their chemotactic response toward CXCL12 or CCL19. The receptor levels after stimulation with LPS plus graded doses of NOR4 are shown in the inserts; the percentages of cells expressing CXCR4 (▪) and CCR7 (♦) are shown in the top and bottom panels, respectively. Data shown are representative of 3 independent experiments.