Figure 5.

CD28^−/− recipients do not develop chimerism with anti-CD154 and allogeneic BMT. Blocking anti-CD28 mAb does not impair the establishment of chimerism in WT recipients. (A) All animals received 3 Gy TBI on day 0, anti-CD8 mAb on day − 1, and 20 × 10⁶ B10.A BMCs. In contrast to 100% (5 of 5) of WT recipients, only 1 of 5 CD28^−/− recipient mice developed chimerism when treated with anti-CD154 and CD8-depleting mAb. None of 5 CD28^−/− mice receiving CD8-depleting mAb alone developed chimerism. (B) In WT recipients of anti-CD154 and CD8-depleting mAb, 8 of 10 mice that also received anti-CD28 developed lasting chimerism (> 30 weeks after BMT), similar to mice that received only anti-CD154 (8 of 9).