Recipient B6-wt (Thy1.2) mice were conditioned with either a single 8.0-Gy TBI dose (day −1) or 4 daily 2.0-Gy TBI doses (days −4, −3, −2, and −1). On day 0, all recipients received 5 × 106 B6-Thy1.1 TCD-BM. One month posttransplant, spleen and lymph nodes cells were harvested and analyzed for Foxp3+ cells of donor (Thy1.1+) and host (Thy1.1−) origin. (A) Representative Foxp3 phenotype of the CD4+CD25+ T cells and percentage of donor versus host cells in spleen (8.0 Gy: 25.0 vs 69.3; 2.0 Gy × 4: 21.5 vs 65.6) and lymph node (8.0 Gy: 22.2 vs 69.9; 2.0 Gy × 4: 23.1 vs 68.4). (B) Individual analysis of spleen and lymph nodes for the total percentage of the CD4+Foxp3+ T cells in 8.0 Gy vs 2.0 Gy × 4 recipients and the percentage of this population, which are of host origin; N = 4/group.
