Figure 1. Kinetics of ICAM-1 reduction on KB cells treated with purified gingipains. (A) KB cells were treated with the given concentrations of purified HRgpA, RgpB, and Kgp for the period indicated at 37°C. After being washed with PBS, the cells were stained with anti-ICAM-1 mAb or matched-isotype mAb and analyzed by flow cytometry. (B) Representative FACS profile of ICAM-1 expression on KB cells after treatment with 1 and 0.3 µmol/L HRgpA for 1 hr at 37°C. Isotype-matched IgG1 was used as a control. (C) KB cells were treated with the given concentrations of HLE for 1 hr at 37°C, and then stained with anti-ICAM-1 mAb or matched-isotype mAb and analyzed by flow cytometry. Representative findings of three independent experiments are expressed as the mean of the MFI (% of control). *P < 0.05 and **P < 0.01 vs. respective untreated cells at each time point.