Costimulatory blockade with anti-CD154 or anti-CD152 mAb potentiates conditioning. NOD mice were pretreated with anti-CD154 (□), anti-CD152 mAb (▴), or the combination of both mAbs (○) and conditioned with decreasing doses of TBI and transplanted with 30 × 10⁶ B10.BR BMC 4-6 hours after TBI. indicates no mAb. The percentage of recipients that engrafted at each TBI dose is shown for each preconditioning approach. n = at least 8 animals per group.