FIG. 3.

HIV-1 protease inhibitors block the LPS activation of IL-6 promoter. HMEC were transiently transfected with IL-6 promoter luciferase and β-galactosidase cDNA as described in Materials and Methods. Cells were treated with nelfinavir, saquinavir, ritonavir, or indinavir for 1 h prior to stimulation with LPS (50 ng/ml) for 5 h. IL-6 promoter activation was assessed by measuring the luciferase activity with a Promega luciferase assay kit and a luminometer. β-Galactosidase colorimetric assays were performed to normalize for transfection efficiency. LPS-induced IL-6 promoter activation is reported as 100%. The results are expressed as percentages of luciferase activity for three or more independent experiments and are reported as means ± SD. *, P < 0.05.