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目的 :探讨向SCID小鼠移植甲氧基聚乙二醇 (mPEG)修饰的人脐血单个核细胞时 ,因供体淋巴细胞表面抗原被遮蔽降低了移植物抗宿主病 (GVHD)而不影响其干祖细胞造血功能重建。方法 :(1)用流式细胞仪检测修饰前后人脐血单个核细胞中CD4 + 、CD8+ T细胞及CD4 + /CD8+ T细胞比率的变化。 (2 )观察遮蔽前后 ,人脐血干祖细胞在体外培养形成CFU GM的差异。 (3)将修饰前后的单个核细胞移植到SCID小鼠体内 ,观察GVHD出现的时间和小鼠活存状况。 (4)移植后 7wk左右测定小鼠骨髓中人源CD4 5 + 细胞的含量。结果 :(1)mPEG几乎可完全遮蔽T细胞表面的CD4和CD8抗原。 (2 )修饰前、后的干祖细胞 ,体外培养形成CFU GM的数量没有明显差异。 (3)将修饰的人脐血单个核细胞移植到小鼠体内 ,GVHD出现的时间晚于未修饰组 ,提高了小鼠的活存率。 (4)移植后 4 7d ,活杀小鼠的骨髓细胞中 ,可检测到人的CD4 5 + 细胞。结论 :用mPEG遮蔽供体T细胞表面的CD4、CD8抗原 ,最终减轻了宿主对移植物的免疫应答 ,而干祖细胞增殖、分化的功能未受到明显影响。
OBJECTIVE: To investigate the effect of mGEG-modified human umbilical cord blood mononuclear cells transplanted to SCID mice on graft-versus-host disease (GVHD) by masking donor lymphocyte surface antigen without affecting Its stem and progenitor cells hematopoietic function reconstruction. Methods: (1) The changes of CD4 +, CD8 + T cells and CD4 + / CD8 + T cells in human umbilical cord blood mononuclear cells before and after modification were detected by flow cytometry. (2) To observe the difference of CFU GM cultured human umbilical cord blood stem and progenitor cells before and after shading. (3) The mononuclear cells before and after modification were transplanted into SCID mice to observe the appearance of GVHD and the survival status of mice. (4) Determination of the amount of human CD4 5 + cells in mouse bone marrow after about 7 weeks after transplantation. Results: (1) mPEG almost completely blocked CD4 and CD8 antigens on T cells. (2) There was no significant difference in the number of CFU GM cultured in vitro before and after modification of stem progenitor cells. (3) The modified human umbilical cord blood mononuclear cells transplanted into mice, GVHD appeared later than the unmodified group, improve the survival rate of mice. (4) Human CD4 + cells were detected in bone marrow cells of live mice on day 47 after transplantation. CONCLUSION: Using mPEG to mask the CD4 and CD8 antigens on the surface of donor T cells, the host immune response to the graft is eventually reduced. However, the function of stem and progenitor cells proliferation and differentiation is not significantly affected.