《自然—免疫學(xué)》上的一篇報(bào)告介紹了在人體骨髓中發(fā)現(xiàn)的一類獨(dú)特細(xì)胞群。該細(xì)胞群可以表達(dá)L-選擇素,，該表達(dá)過程是已知的特定種類白細(xì)胞產(chǎn)生的最早階段,。該細(xì)胞群的發(fā)現(xiàn)將有助我們了解正常血細(xì)胞的發(fā)育并可能找到在引起各類白血病的細(xì)胞不穩(wěn)定發(fā)育中的重要線索。
Gay Crooks等人通過人體干細(xì)胞/祖細(xì)胞移植手段讓免疫缺陷小鼠發(fā)育出血細(xì)胞,，然后對(duì)比觀察人體骨髓細(xì)胞在該小鼠體內(nèi)和培養(yǎng)皿中的發(fā)育情況,。他們發(fā)現(xiàn)骨髓細(xì)胞中產(chǎn)生了一種L-選擇素陽(yáng)性細(xì)胞群，該細(xì)胞群屬于一種發(fā)育中間物,，介于靜止造血干細(xì)胞和一種之前發(fā)現(xiàn)的可促使產(chǎn)生抗體B細(xì)胞形成的細(xì)胞群之間,。雖然該選擇素細(xì)胞群缺少制造血紅細(xì)胞和血小板的功能，但其可以產(chǎn)生各種白細(xì)胞，包括T細(xì)胞和自然殺傷細(xì)胞,。
重要的是,，骨髓中這種新發(fā)現(xiàn)的細(xì)胞群與在新生兒臍帶血中發(fā)現(xiàn)的始祖細(xì)胞是不同的。雖然臍帶血細(xì)胞更容易獲取并具有高度增殖特性,，但其在發(fā)育能力方面有更多限制,，而新發(fā)現(xiàn)的骨髓細(xì)胞則更具有普適性。（生物谷Bioon.com）
doi:10.1038/ni.2405
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PMID:
Lymphoid priming in human bone marrow begins before expression of CD10 with upregulation of L-selectin
Kohn LA, Hao QL, Sasidharan R, Parekh C, Ge S, Zhu Y, Mikkola HK, Crooks GM.
Expression of the cell-surface antigen CD10 has long been used to define the lymphoid commitment of human cells. Here we report a unique lymphoid-primed population in human bone marrow that was generated from hematopoietic stem cells (HSCs) before onset of the expression of CD10 and commitment to the B cell lineage. We identified this subset by high expression of the homing molecule L-selectin (CD62L). CD10(-)CD62L(hi) progenitors had full lymphoid and monocytic potential but lacked erythroid potential. Gene-expression profiling placed the CD10(-)CD62L(hi) population at an intermediate stage of differentiation between HSCs and lineage-negative (Lin(-)) CD34(+)CD10(+) progenitors. CD62L was expressed on immature thymocytes, and its ligands were expressed at the cortico-medullary junction of the thymus, which suggested a possible role for this molecule in homing to the thymus. Our studies identify the earliest stage of lymphoid priming in human bone marrow
