Requirement for the PD-1/PD-L1 pathway for CD8 but not CD4 T-cell tolerance. (A) C57BL/6 or PD-1 KO mice (on a C57BL/6 background), CD8 depleted or not, received 20 to 25 × 106 B10.A BM cells with anti-CD154 and 3 Gy TBI. Incidence of chimerism is shown for the B-cell lineage 6 weeks after BMT and is representative of all lineages analyzed. Multilineage chimerism 6 weeks after BMT is shown in Table S1. One representative experiment of 3 total is shown (n = 5-8 animals/group per experiment). (B) B6 mice, CD8 depleted or not, received 20 to 25 × 106 B10.A BM cells with PD-1 and PD-L1 blocking mAbs, anti–PD-L1 alone, anti–PD-1 alone, or control irrelevant IgG2a and/or IgG2b mAbs, anti-CD154, and 3 Gy TBI. Incidence of chimerism is shown for the B-cell lineage 6 weeks after BMT and is representative of all lineages analyzed. Multilineage chimerism 6 weeks after BMT is shown in Table S2. Incidence of chimerism was similar in control group treated with both irrelevant mAbs or with each irrelevant mAb alone. One representative experiment of 2 in total is shown (n = 5-8 animals/group per experiment).
