NK-cell tolerance after treatment with anti-CD40L mAb and 10⁸ donor BMCs is donor-specific. C57BL/6 mice were treated with anti-CD40L mAb in combination with 10⁸ BALB/c BMCs (n = 5) at day 0. At day 28 these mice were given injections of differentially CFSE-labeled MHC-mismatched, C3H/J-derived third-party splenocytes and BALB/c splenocytes; peripheral-blood samples were collected 3 hours, 3 days, and 8 days later for FACS analysis. Survival of the highly CFSE⁺ third-party cells was calculated using the intermediate CFSE⁺ donor cells as internal control cells. Three hours after the infusion of the CFSE-labeled splenocytes, no detectable elimination of the CFSE-labeled third-party cells was observed. Three days later 88.7% ± 6.5% of the third-party cells were eliminated and 8 days later 98.4% ± 1.4% of the cells were eliminated. These elimination kinetics were similar compared to anti-CD40L mAb-treated C57BL/6 mice (data not shown). The displayed dot plots are representative of each time point.