Induction of BM engraftment with CD4, CD8 and CD40L mAbs. (A) CBA mice were treated with three doses of 1 mg of non-depleting CD4, CD8 and CD40L mAbs on days -28, -26, -24, 0, 2 and 4 in relation to the day of BMT (day 0). (B) The level of hematopoietic chimerism was determined among peripheral blood mononuclear cells of CBA mice, transplanted with different numbers of B10 BM, by flow cytometry. CBA mice not subjected to BMT were used as a control group. Results are from day 120 following BMT. Difference from the control group is statistically significant in animals transplanted with 1×107 cells or more (p < 0.02). (C) The mice were transplanted with donor type (B10) skin grafts 50 days following BMT. Grafts survived indefinitely in animals where mixed chimerism had been established, being the difference between animals transplanted with 1×107 BM cells or more, and animals transplanted with 1×106 or 5×106 BM cells statistically significant (p < 0.02).