Effect of LPS on IRF-3 activation in NB-1 cells. NB-1 cells were cultured with LPS at 100 ng/ml for various time as indicated. Cell extracts were analyzed with immunoblotting using an antibody to phosphorylated form of IRF-3 (pIRF-3) (A) or total IRF-3 (B). U937 cells were used as a positive control. Equal loading is shown using anti-actin antibody. A typical experimental result of three independent experiments is shown.