Poly I:C stimulation of RA synovial fibroblasts but not DCs activates nuclear translocation of IRF-3. (A) Human DCs and (B) RA-SFs were either left unstimulated (Un) or stimulated with poly I:C (20 μg/mL) and LPS (100 ng/mL), and the nuclear fractions were examined for nuclear IRF-3 and topoisomerase by Western blotting. Representatives of 3 independent experiments per cell type are shown.