PVR expression on activated T cells is associated with progression to the S and G₂/M phases of the cell cycle. (A) CFSE-labeled PBMCs were activated or not with SEB for 3 days and PVR expression was analyzed by gating CD3⁺ T cells. We used CFSE fluorescence intensity to divide T cells into 2 populations: those that had undergone at least one cell division (CFSE^low) and those that had not divided (CFSE^high). The percentage of cells in each quadrant is reported. One representative donor of the 5 tested is shown. (B) Unstimulated or 3-day SEB-stimulated PBMCs were labeled with BrdU for 1 hour and then stained with anti-PVR mAb plus GAM/PE and anti-BrdU/FITC mAb. The percentage of cells in each quadrant is displayed. One representative donor of the 6 tested is shown. (C) PBMCs were stimulated with SEB for 3 days, stained with anti-PVR mAb plus GAM/allophycocyanin followed by anti–CD3/FITC, and then labeled with PI. CD3⁺ T cells were gated in the different phases of the cell cycle according to DNA content, and PVR expression was analyzed. The MFI value of the isotypic control mAb was subtracted from the MFI values of PVR. A summary of the MFI mean value ± SD from 5 donors is shown. Statistical analysis was with the Student paired t test.