人胸腺和脐血造血干/祖细胞联合移植对裸鼠T细胞免疫功能影响

Influence of transplantation with human thymus tissue and cord blood hemotopoietic stem/progenitor cells on T cell immune function

目的:建立人胸腺和脐血造血干/祖细胞联合移植裸鼠动物模型,探讨胸腺对造血干细胞发育分化的机制。方法:实验组为人胸腺与脐血CD34+细胞联合移植,对照组只给予人脐血CD34+细胞移植,通过观察裸鼠移植胸腺CD3、HLA-DR的表达、人源CD3+细胞在小鼠脾脏的表达、裸鼠血液CD3+、CD4+、CD8+和CD4+CD25+细胞的百分比,以及联合移植裸鼠对移植肿瘤的排斥能力,判断联合移植对裸鼠免疫功能的影响。结果:移植胸腺在裸鼠肾被膜下存活,表达CD3和HLA-DR分子;裸鼠脾脏中检测到人源CD3+T细胞呈点块状分布;裸鼠血液中CD3+、CD4+、CD8+、CD4+CD25+细胞均增高,与对照组比较差异有统计学意义(P<0.05);联合移植组能抵抗肿瘤细胞的生长,单独脐血造血干/祖细胞移植组不能抑制肿瘤生长。结论:裸鼠移植人胸腺能促进人脐血造血干/祖细胞向T细胞分化、促进免疫功能重建。

Objective To establish nude mice model by transplantation with human thymus tissue and cord blood hemotopoietic stem/progenitor cells for studying the effect of the thymus on the differentiation of cord blood stem cells.Methods The experimental group received thymus and umbilical CD34＋ transplantation,and control group received umbilical CD34＋ transplantation.The immune effect of combined transplantation nude mice was studied by observing the expressions of CD3 and HLA-DR in spleen and transplanted thymus.The percentages of CD3＋ cells,CD4＋cells,CD8＋cells and CD4＋CD25＋ cells and the rejection to tumor were observed.Results The transplanted thymus survived in renal capsule,expressing CD3 and HLA-DR.CD3＋T showed spot-like distribution in nude mice spleen.The levels of CD3＋,CD4＋,CD8＋ and CD4＋CD25＋cells raised up,which were significantly different from those in control group.The combined transplantation could prevent tumor cell from growing,and the single transplantation could not.Conclusion The human thymus in nude mice may promote the umbilical hematopoietic stem/progenitor cells differentiation to T cell and promote the immune function reconstruction.