FIG. 3.

The 5′-flanking region of the ICAM-1 gene confers RSV responsiveness in A549 cells. A549 cells were transfected with pBH5000 and infected with RSV (multiplicity of infection, 1) for the indicated times, and then cell lysates were harvested for measurement of luciferase and β-Gal activities. ICAM-1 gene activation (measured as luciferase reporter gene activity) is significantly increased in A549 cells transfected with pBH5000 at all time points after RSV infection. However, luciferase activity is greatest at the 6-h time point, compared to the 2-h and 24-h time points. Results are the average of six replicate samples. Luciferase activity is normalized to the β-Gal activity of that sample in order to correct for transfection efficiency. Results are representative of two separate experiments. Error bars represent standard deviations. ∗∗, P is <0.01 compared to uninfected controls; †, P is <0.01 compared to 6-h RSV-infected cells.