CD8⁺ T-cell-depleted IFN-γ^-/- recipients achieve high levels of multilineage donor chimerism following treatment with 3 Gy TBI, anti-CD154 mAb, and BMT. All animals received 3 Gy TBI and 20 × 10⁶ Balb/c IFN-γ^-/- BMCs. (A) Seven of 8 CD8-depleted WT and 8 of 8 IFN-γ^-/- mice treated with anti-CD154 developed lasting chimerism for more than 20 weeks. None of the CD8-depleted IFN-γ^-/- mice receiving BM transplants without MR1 developed lasting chimerism. (B) Mean percentages plus standard deviation of donor-derived B cells in chimeric WT and IFN-γ^-/- recipients at various times after BMT as measured by flow cytometry. Similar results were observed in the CD4, CD8, monocyte, and granulocyte populations (data not shown).