Abstract: To establish a mouse model of nonmyeloablative bone marrow transplantation, we used fe-male C57BL/6 （H-2b） mice as recipients and male BALB/c （H-2d） mice as donors.The re-cipients received Cyclophosphamide （200mg/kg） and total body irradiation （5 Gy）.This regime is nonmyeloablative On the 36th day after transplantation，we detected the Y chromosome specific gene in bone marrow cells of recipients mice. We found that engraftment of allogeneic hematopoietic stem cells can be established under the nonmyeloablative pretreatment regime.We also found that the number of hematopoietic stem cells is very important for the success rate of making model.The rate of engraftment is 80% （8/10） when the recipients mice were given 2 × 10⁷ bone marrow cells.

Key words: Nonmyeloablative, Bone marrow transplantation, Mouse