反向骨髓移植诱导异种造血嵌合体的研究

Study on the induction of xenogeneic (rat-mouse) hematopoietic chimerism by reverse bone marrow transplantation

目的 应用大鼠 小鼠骨髓移植模型 ,探讨反向骨髓移植诱导特异性免疫耐受的作用机制。方法 首先诱导形成嵌合体SD大鼠 ,再将此嵌合体大鼠的骨髓反向移植给Balb c小鼠 ,监测存活率 ,GVHD发病率 ,做混合淋巴细胞培养 ,检测脾细胞增殖及TNF α、INF γ与IL 4产量 ,监测移植后小鼠嵌合率的变化。结果 对照组小鼠观察期间出现严重GVHD表现 ,反向移植组小鼠仅出现轻度GVHD ,生存期明显延长 ,TNF α与INF γ产量明显降低 ,而IL 4升高 ,移植后嵌合率较稳定 ,与对照组相比有显著性差异。结论 有受者嵌合体的骨髓移植可以减轻急性GVHD 。

Objective To explore the role of reverse bone marrow transplantation (BMT) in induction of specific xenogeneic immune tolerance. Methods The rat model of BALB/c→SD xenogeneic chimera was established, and then the lethally irradiated BALB/c mice received 4×10 7 bone marrow cells from the chimera rats. Survival rate was monitored daily and GVHD clinical score was measured weekly. Recipient splenic cells were stimulated in mixed lymphocyte culture (MLC) with xenoantigen at day 14, then TNF-α, INF-γ, and IL-4 production in culture supernatants were measured by ELISA. Donor cell engraftment was determined by examining percentage of rat origin cells in periphe- ral blood at day 30, 60, and 90. Results The morbidity and mortality of acute GVHD were significantly reduced, and the survival time was obviously prolonged. Splenic cells showed a great increase in IL-4 production with a simultaneous decrease in INF-γ and TNF-α production, and the serum cytokine levels were consistent with the experiment in vitro. More stable xenogeneic chime- rism over 90 d was achieved via reverse BMT. Conclusion The result shows that reverse bone marrow transplantation alleviates acute GVHD and induces long-term xenogeneic chime- rism by inhibiting type 1 cytokine production and polarizing donor T lymphocytes toward type 2.