Cigarette smoke extract treatment caused NF-κB RelA/p65 nuclear translocation in primary human small airway epithelial cells. Primary human small airway epithelial cells were grown in 8-well chamber slides and were exposed for 20 min. to CSE (1.0%) prepared from 1R3F research grade cigarettes. TNF-α (10 ng/ml) was used as a positive. After treatment period, the cells were incubated with NF-κB RelA/p65 antibody and were visualized under fluorescent microscope. Cigarette smoke extract and TNF-α treatments caused nuclear translocation of NF-κB RelA/p65.