PBMCs were stimulated with SEB. After 48 hours, NAC was added to the cultures and left for an additional 18 hours. Cells were stained with specific mAbs plus GAM/PE and with anti–CD3/PECy5 mAb. NKG2DL expression was analyzed on CD3+CFSElow T cells. The MFI of isotypic control mAb was subtracted from the MFI of NKG2DL. The mean of MFI values of 6 different donors ± SD is shown. Statistical analysis was with the Student paired t test.