Establishment of a nonmyeloablative allogeneic peripheral blood stem cell transplantation model in mice and its related study

Objective To explore the effect of different types of infusion of allogeneic hematopoietic stem cells transplantation(HSCT) combined with donor lymphocytes infusion(DLI) on chimerism rate and incidence of graft-versushost disease(GVHD).Methods Female C57BL/6 mice(H-2b,B6) as recipients received total body irradiation(TBI),followed by the tail vein infusion(VI) or intra-bone marrow infusion(IBM) of allogeneic hematopoietic stem cells(3×107) transplantation(allo-HSCT) from mobilized male BALB/c with granulocyte-colony stimulating factor(rhG-CSF) and DLI(5×106),cyclophosphamide(200 mg/kg) was injected intraperitoneally two days later.Results Mixed chimeras was detected in all groups on day 7.The rate of mixed chimeras of IV-PBSCT-DLI group was much higher than the others.The GVHD was presented in the group of transplantation by VI,in which the IV-PBSCT-DLI group was more significant.However,there was no GVHD in the group which was transplanted by IBM.CD4+CD25+ obviously declined in IV-PBSCT-DLI group while rose in the IBM-PBSCT or IBM-PBSCT-DLI group.Conclusion Mixed-chimerism can be achieved by using a nonmyeloablative TBI and CTX-based conditioning regimen in combination with infusion of peripheral blood stem cells mobilized by rhG-CSF in fully H-2-mismatched recipient mice.DLI evidently promotes the donor chimers and the incidence of GVHD is reduced remarkably.Additionally,the mechanism involved in this process is probably associated with the changes of T-cell sub-group.