FIG. 6.

Up-regulated IFN-γR expression does not increase STAT-1 activation. HeLa 229 cells cultivated in complete medium, treated with IL-1β (100 ng/ml), or infected with C. psittaci for 12 h were induced with IFN-γ (20 ng/ml) for 4 h. Nuclei were isolated, and phosphorylated STAT-1 levels were assessed by flow cytometric analysis using an anti-STAT-1P Tyr 701 antibody. The results are representative of several independent experiments with similar results (mean fluorescent intensities [MFI] ± standard deviations).