Figure 3. Preferential reduction of ICAM-1 on oral epithelial cells by Rgp, and effect of serum on the ICAM-1 proteolysis. (A) KB cells were treated with or without 0.3 µmol/L HRgpA for 1 hr at 37°C. After being washed with PBS, cells were stained with anti-ICAM-1, CD29, CD48, CD49b, CD49e, CD58, CD13, and MHC class I or matched-isotype mAb and analyzed by flow cytometry. (B) KB cells were treated with 0.3 µmol/L HRgpA for 1 hr in the presence or absence of 3 µmol/L FPR-cmk or 3 µmol/L Z-FK-cmk, or treated with 1 µmol/L HRgpA for 1 hr in the presence or absence of the indicated concentrations of freshly isolated human serum. After a wash with PBS, the expression of ICAM-1 was 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 control.