Figure 1

IFNγ modulates release of IL-8 by IL-1β-stimulated A549 cells. (A) A549 cells were incubated as unstimulated control, or stimulated with the indicated concentrations of IL-1β. After 24 h, cell-free supernatants were assayed for IL-8 protein content by ELISA analysis. Data are expressed as mean IL-8 concentrations ± SD (n = 4). **p < 0.01 compared with untreated control. (B) A549 cells were incubated as unstimulated control, stimulated with IL-1β (25 ng/ml), or with IL-1β (25 ng/ml) in combination with the indicated concentrations of IFNγ. After 24 h, cell-free supernatants were assayed for IL-8 content by ELISA analysis. Data are expressed as mean IL-8 concentrations ± SD (n = 8). **p < 0.01 compared with IL-1β alone. (C) A549 cells were incubated as unstimulated control or were stimulated with IL-1β (25 ng/ml). Where indicated, A549 cells were preincubated for 16 h with IFNγ at different concentrations (ranging from 3.1 ng/ml up to 25 ng/ml). IL-1β was added directly thereafter to the cultures without further washing. After the indicated time periods with or without IL-1β stimulation, cell-free supernatants were assayed for IL-8 content by ELISA analysis. Data are expressed as mean IL-8 concentrations ± SD (n = 7). **p < 0.01 (for IFNγ at 3.1 ng/ml) compared with IL-1β alone.