非清髓性预处理联合髓腔内骨髓细胞输注诱导免疫耐受的实验研究

目的本研究通过非清髓性预处理方案联合髓腔内骨髓移植建立异基因小鼠免疫耐受模型,并探讨其诱导耐受的机理.方法受鼠C57BL/6(B6)于第0天接受60Coγ射线全身照射(TBI,550-cGy),4 h内输注雄性BALB/C(H2d)小鼠来源的骨髓细胞,2 d后腹腔注射环磷酰胺(CTX,200 mg·kg-1).通过皮肤移植、混合淋巴细胞反应(mixed lymphocyte reaction, MLR)检测耐受状态,并应用体外过继转移实验、IL 2逆转实验等探讨免疫耐受机制.结果经骨髓移植的B6小鼠对BALB/C小鼠的皮肤移植物平均存活时间超过300d,较空白组明显延长(P＜0.001);MLR结果证明B6小鼠获得供体特异性耐受,该耐受可以被IL 2逆转且可被过继转移;所有受鼠均未出现GVHD表现.结论非清髓预处理联合髓腔内骨髓移植可以有效诱导异基因小鼠的免疫耐受.

Durable immune tolerance induced by a nonmyeloablative conditioning approach combined with intra-bone marrow injection of allogeneic bone marrow cells

To explore the effect and mechanisms of immune tolerance induced by total body irradiation(TBI)+cyclophosphamide(CTX) regimen combined with intra-bone marrow (IBM)injection of allogeneic bone marrow cells (BMCs).Methods Recipient mice C57BL/6(B6) received TBI 550cGy (60Co γ-ray) followed by IBM injection of BMCs from BALB/c, CTX were given 200 mg·kg-1 intraperitoneally (i.p.)2 days following bone marrow transplantation (BMT). On day 7 skin grafting was performed and the mean survival time(MST)was observed. The tolerance mechanisms were investigated through mixed lymphocyte reaction(MLR), IL-2 reverse test, adoptive transfer assay.Results The MST of donor-type skin allografts in group treated with TBI+CTX+IBM-BMT was significantly longer compared with control group (P<0.001). The MLR demonstrated that the immune response of recipient mice was donor-specifically inhibited. Suppressive activity in the spleens of tolerant B6 mice was observed in adoptive transfer assay in vitro. IL 2 reverse test showed that clonal anergy was involved in the development of immune tolerance, and no signs of graft-versus-host disease(GVHD) were observed. Conclusion A stable donor-specific tolerance status can be achieved using a nonmyeloablative conditioning regimen combined with IBM-BMT.