Induction of hBD-2 promoter activity by proinflammatory cytokine IL-1β in A549 cells. A549 cells were transfected with the luciferase plasmid containing hBD-2 promoter for 20 h and stimulated with the indicated concentrations of IL-1 β for 6 h. The cells were harvested and assayed for luciferase activity as described in Methods. Luciferase activities were expressed as a fold-activation relative to the un-stimulated control. Values are mean ± SD of five independent experiments. *, P < 0.0001.