Gotze K S, Ramirez M, Tabor K, Small D, Matthews W, Civin C I
Division of Pediatric Oncology, Department of Oncology, Johns Hopkins University School of Medicine, Baltimore MD 21287-5001, USA.
Blood. 1998 Mar 15;91(6):1947-58.
We generated monoclonal antibodies against the human Flt3 receptor and used them to study the characteristics of normal human bone marrow cells resolved based on Flt3 expression. Human CD34+ or CD34+lin- marrow cells were sorted into two populations: cells expressing high levels of Flt3 receptor (Flt3high) and cells with little or no expression of Flt3 receptor (Flt3low). Flt3 receptor was detected on a subset of CD34+CD38- marrow cells, as well as on CD34+CD19+ B lymphoid progenitors and CD34+CD14+CD64+ monocytic precursors. Flt3 receptor was also present on more mature CD34-CD14+ monocytes. In colony-forming assays, Flt3high cells gave rise mainly to colony-forming unit-granulocyte-macrophage (CFU-GM) colonies, whereas Flt3low cells produced mostly burst-forming unit-erythroid colonies. There was no difference in the number of multilineage CFU-Mix colonies between the two cell fractions. Cell cycle analysis showed that a large number of the Flt3low cells were in the G0 phase of the cell cycle, whereas Flt3high cells were predominantly in G1. Cell numbers in the suspension cultures initiated with Flt3high cells were maintained in the presence of Flt3 ligand (FL) alone, and increased in response to FL plus kit ligand (KL). In contrast, cell numbers in the suspension cultures started with Flt3low cells did not increase in the presence of FL, or FL plus KL. Upregulation of Flt3 receptor on Flt3low cells was not detected during suspension culture. CD14+ monocytes were the major cell type generated from CD34+lin-Flt3high cells in liquid suspension culture, whereas cells generated from CD34+lin-Flt3low cells were mainly CD71+GlycA+ erythroid cells. These results show clear functional differences between CD34+Flt3high and CD34+Flt3low cells and may have implications concerning the in vitro expansion of human hematopoietic progenitor cells.
我们制备了针对人Flt3受体的单克隆抗体，并利用它们来研究基于Flt3表达分离的正常人骨髓细胞的特性。将人CD34+或CD34+lin-骨髓细胞分为两个群体：表达高水平Flt3受体的细胞（Flt3high）和几乎不表达或不表达Flt3受体的细胞（Flt3low）。在一部分CD34+CD38-骨髓细胞以及CD34+CD19+B淋巴细胞祖细胞和CD34+CD14+CD64+单核细胞前体上检测到了Flt3受体。Flt3受体也存在于更成熟的CD34-CD14+单核细胞上。在集落形成试验中，Flt3high细胞主要产生集落形成单位-粒细胞-巨噬细胞（CFU-GM）集落，而Flt3low细胞大多产生爆式红系集落形成单位集落。两个细胞组分之间的多谱系CFU-Mix集落数量没有差异。细胞周期分析表明，大量Flt3low细胞处于细胞周期的G0期，而Flt3high细胞主要处于G1期。以Flt3high细胞起始的悬浮培养物中的细胞数量在仅存在Flt3配体（FL）时保持稳定，并在FL加kit配体（KL）的刺激下增加。相反，以Flt3low细胞起始的悬浮培养物中的细胞数量在存在FL或FL加KL时没有增加。在悬浮培养过程中未检测到Flt3low细胞上Flt3受体的上调。在液体悬浮培养中，CD14+单核细胞是由CD34+lin-Flt3high细胞产生的主要细胞类型，而由CD34+lin-Flt3low细胞产生的细胞主要是CD71+GlycA+红系细胞。这些结果显示了CD34+Flt3high和CD34+Flt3low细胞之间明显的功能差异，可能对人造血祖细胞的体外扩增具有重要意义。
