人胎盘造血干/祖细胞及淋巴细胞亚群表型的研究

目的　探讨人胎盘组织中是否含有造血干 祖细胞 (HSPC) ,并分析其淋巴细胞亚群的表型特征。方法　将新鲜胎盘制成单个细胞悬液 ,用流式细胞仪分析其有核细胞中HSPC、淋巴细胞及其亚群的表型特征 ,并用流式细胞术 (FCM)或MiniMACS分选胎盘CD34 细胞。结果　胎盘CD34 细胞百分率是脐带血的 8.8倍 ,CD34 CD38- 细胞和CD34 CD38 细胞百分率分别为脐带血的 4 .6倍和 11.9倍 ;FCM分选胎盘CD34 细胞的回收率和纯度分别为 (6 3.0 5± 10 .14 ) %和 (86 .39± 11.2 7) % ;胎盘中的淋巴细胞总数、T细胞 (CD3 CD2 )、B细胞 (CD1 9 )、Th(CD3 CD4 )细胞及Th Ts比值均明显低于脐带血 ,而CD8 CD2 8- T抑制细胞则明显高于脐带血。结论　人胎盘富含HSPC ,在胎儿期具有重要的造血功能 ,可望成为HSPC移植的重要资源。CD8 CD2 8- T抑制细胞可能在胎 母免疫耐受中起重要作用。

Hematopoietic stem/progenitor cells and phenotypes of lymphocyte subpopulations in human placenta

OBJECTIVE: To study whether human placenta contains hematopoietic stem/progenitor cells (HSPCs), and analyze phenotypes of lymphocyte subpopulations in the placenta. METHODS: Nucleated cells from fresh human placenta were analyzed for phenotypes of HSPCs and lymphocyte subpopulations by flow cytometry (FCM). And CD(34)(+) cells were sorted from human placenta nucleated cells by FCM or MiniMACS. RESULTS: (1) CD(34)(+) cells, CD(34)(+)/CD(38)(+) cells, and CD(34)(+)/CD(38)(-) cells from a human placenta were 8.8, 4.6 and 11.9 times higher than those from umbilical cord blood (UCB), respectively. (2) The yields and purity of CD(34)(+) cells isolated from human placenta by FCM sorting system were (63.05 +/- 10.14)% and (86.39 +/- 11.27)%, respectively. (3) Lymphocytes, T cells (CD(3)(+)/CD(2)(+)), B cells (CD(19)(+)), Th cells (CD(3)(+), CD(4)(+)), and Th/Ts ratio in the placenta tissue were apparently lower than those in the UCB, while the CD(8)(+)/CD(28)(-) T suppressor cells were higher in the placenta than in the UCB. CONCLUSIONS: Human placenta is rich in HSPCs, and has important hematopoietic function in ontogeny. It is probable that human placenta would be graft resource for HSPCs transplantation. CD(8)(+)/CD(28)(-) T suppressor cells might play an important role in feto-maternal immunologic tolerance.