Watt S M, Gilmore D J, Davis J M, Clark M R, Waldmann H
Imperial Cancer Research Fund, Medical Oncology Unit, London, UK.
Mol Cell Probes. 1987 Dec;1(4):297-326. doi: 10.1016/0890-8508(87)90013-2.
Within the last decade, major advances have been made in the analysis of cell-surface marker expression on haemopoietic progenitor cells as a result of the development of multiparameter cell sorting and monoclonal antibody techniques. Although some controversy exists with regard to the actual identification of the stem cell, markers specific for CFU-s and for particular subsets of progenitor cells have not yet been identified. An analysis of cell-surface markers on haemopoietic progenitor cells is complicated by at least three factors. First, it appears that, in mice, the clonal assays do not adequately identify the haemopoietic stem cell. Complete repopulation of all haemopoietic cell compartments in vivo over an extended period of time appears to be the only reliable method for identifying such a cell. Secondly cell-surface marker distribution on haemopoietic progenitors from normal tissues may be indicative of the cycling status of cells. Thus, expression of markers on progenitors from bone marrow or foetal liver which have been perturbed by drugs or viruses may merely reflect a change in their cycling status following drug or viral insult. Thirdly, substantial loss of cells occurs during the purification of particular cell types. For most cell separation procedures, only a minor proportion of the progenitor cells of interest are recovered and these may not be representative of the progenitor population as a whole. During differentiation to mature cells, antigenic determinants present on early progenitor cells may either be progressively lost or amplified. This differential expression of cell-surface molecules has provided a useful tool for the substantial enrichment of haemopoietic subsets, particularly CFU-E and CFU-s. To date, however, most early haemopoietic progenitor cells detected by in vitro CFC assays (day 8 CFC) cannot be completely segregated from one another. The ability to distinguish between such progenitors during the early stages of lineage commitment would provide a more detailed understanding of the relationship between lymphoid precursors, myeloid precursors and stem cells, and would lead to significant advances in developmental biology. Separation of cells at different stages of differentiation within a given lineage would provide an opportunity for studying regulatory mechanisms involved in gene expression in normal cell populations.
在过去十年中，由于多参数细胞分选和单克隆抗体技术的发展，造血祖细胞表面标志物表达分析取得了重大进展。尽管在干细胞的实际鉴定方面存在一些争议，但尚未鉴定出CFU-s和特定祖细胞亚群的特异性标志物。造血祖细胞表面标志物的分析至少受到三个因素的影响。首先，在小鼠中，克隆分析似乎不能充分鉴定造血干细胞。在体内长时间完全重建所有造血细胞区室似乎是鉴定这种细胞的唯一可靠方法。其次，正常组织中造血祖细胞的细胞表面标志物分布可能表明细胞的循环状态。因此，受到药物或病毒干扰的骨髓或胎肝祖细胞上标志物的表达可能仅仅反映了药物或病毒损伤后其循环状态的变化。第三，在特定细胞类型的纯化过程中会发生大量细胞损失。对于大多数细胞分离程序，仅回收了一小部分感兴趣的祖细胞，而这些细胞可能不代表整个祖细胞群体。在分化为成熟细胞的过程中，早期祖细胞上存在的抗原决定簇可能会逐渐丢失或扩增。细胞表面分子的这种差异表达为大量富集造血亚群，特别是CFU-E和CFU-s，提供了一种有用的工具。然而，迄今为止，通过体外CFC分析（第8天CFC）检测到的大多数早期造血祖细胞彼此之间无法完全分离。在谱系定向的早期阶段区分这些祖细胞的能力将提供对淋巴样前体、髓样前体和干细胞之间关系的更详细理解，并将导致发育生物学的重大进展。在给定谱系内不同分化阶段分离细胞将为研究正常细胞群体中基因表达所涉及的调节机制提供机会。
