Abstract: Objective To explore the effect of α- galactosyleramide( α-GalCer ) on immune reconstitution under acute graft-versus-host disease (aGVHD). Methods BALB/c mice were transplanted wit hallogeneic C57BL/6 bone marrow cells and splenocytes (both 1×10⁷)after receiving lethal total-body irradiation. α-GalCer (100 ug/kg) or vehicle (dimethylsulfoxide) was administered intraperitoneally immediately after transplantation. The effects of α-GalCer on immune reconstitution,proliferation of T cells and B cells, hematopoiesis,and thymic microenvironment were assessed. Results The α-GalCer group exhibited higher percentages of CD3⁺,CD4⁺, CD8⁺, B220⁺, CD40⁺, and CD86⁺cells compared with the vehicle group . The number of colony forming unit per 1000 CD34⁺ cells in the α-GalCer group was higher than in the vehicle group ( P=0.0012).In vitro proliferation assays showed that the α-GalCer group had higher percentages of CD3⁺, CD4⁺, CD8⁺,and B220⁺ cells compared with the vehicle group. As for the results of in vivo proliferation assays, the numbers of CD3⁺, CD4⁺, CD8⁺, and B220⁺cells were higher in the α-GalCer group than in the normal group ,especially the number of B220⁺ cells ( P=0.007).Significant difference was not found in thymocyte count between the α-GalCer group and the vehicle group, nor in the percentages of CD3⁺, CD4⁺, and CD8⁺ cells.Conclusion Administration of α-GalCer after allogeneic bone marrow transplantation may promote immune reconstitution in the presence of aGVHD.

Key words: immune reconstitution, α-galactosyleramide, bone marrow transplantation