CD80/86 expression is not required on donor BMCs for the induction of mixed chimerism in mice treated with anti-CD154. B6 WT and CD80/86^−/− mice were used as bone marrow donors into B10.S recipient mice that received anti-CD8, 3 Gy TBI, and anti-CD154. In both groups, all of the mice (7 of 7 for each group) developed long-term mixed chimerism (> 10 weeks) in all lineages. Donor chimerism (mean ± SD shown) was detected in CD4, CD8, B-cell, monocyte, and granulocyte lineages by FCM analysis for more than 13 weeks after BMT.