Reisbach G, Bartke I, Kempkes B, Kostka G, Ellwart J, Birner A, Thalmeier K, Mailhammer R, Bornkamm G W, Ullrich A
GSF-Institute of Experimental Hematology, Munich, Germany.
Exp Hematol. 1993 Jan;21(1):74-9.
Human cord blood or bone marrow cells expressing the CD34 surface antigen include a population of pluripotent progenitors. We identified and isolated a subpopulation of cells coexpressing CD34 and c-kit, a transmembrane receptor with tyrosine kinase activity. Novel monoclonal antibodies (16A6, 14A3, 3D6) directed against the extracellular domain of c-kit were used for immunofluorescence labeling and sorting of low-density mononuclear cells (MNCs) from umbilical cord blood and bone marrow. The frequency of c-kit-labeled MNCs from cord blood (mean 5.0% +/- 2.1%, n = 16) was similar to that from adult bone marrow (mean 3.7% +/- 1.3%, n = 4). On average, 1.4% of CD34-positive cells were recorded in cord blood and 2.1% in bone marrow MNCs. Roughly 60% of CD34-positive cells coexpressed c-kit. The ability of CD34+/c-kit+ cells to form multilineage colonies (CFU-GEMM) was assayed after sorting with an antibody that did not show any significant effect on c-kit ligand (RL) or granulocyte/macrophage colony-stimulating factor (GM-CSF)-induced colony formation. For CD34+/c-kit+ cells, we found a 20- to 50-fold enrichment as against total MNCs, and a 2-fold enrichment if compared with the CD34+/c-kit-population. To study expression of c-kit in lymphocytic precursors, monoclonal anti-CD7 or anti-CD10 antibodies were used simultaneously. In contrast to CD34-expressing cells, however, no consistent double-labeled subpopulation of lymphocytic cells was detected. Furthermore, coexpression of CD38 (73% +/- 14%, n = 4) or CD33 (29% +/- 12%, n = 5) on a majority of c-kit-positive cells showed their lineage commitment to erythropoiesis and granulocytopoiesis.
表达CD34表面抗原的人脐带血或骨髓细胞包含一群多能祖细胞。我们鉴定并分离出了共表达CD34和c-kit的细胞亚群，c-kit是一种具有酪氨酸激酶活性的跨膜受体。针对c-kit胞外结构域的新型单克隆抗体（16A6、14A3、3D6）用于对来自脐带血和骨髓的低密度单核细胞（MNC）进行免疫荧光标记和分选。来自脐带血的c-kit标记的MNC频率（平均5.0%±2.1%，n = 16）与来自成人骨髓的频率（平均3.7%±1.3%，n = 4）相似。平均而言，脐带血中记录到1.4%的CD34阳性细胞，骨髓MNC中为2.1%。大约60%的CD34阳性细胞共表达c-kit。在用对c-kit配体（RL）或粒细胞/巨噬细胞集落刺激因子（GM-CSF）诱导的集落形成没有任何显著影响的抗体进行分选后，检测了CD34+/c-kit+细胞形成多谱系集落（CFU-GEMM）的能力。对于CD34+/c-kit+细胞，我们发现相对于总MNC有20至50倍的富集，与CD34+/c-kit-群体相比有2倍的富集。为了研究c-kit在淋巴细胞前体中的表达，同时使用了单克隆抗CD7或抗CD10抗体。然而，与表达CD34的细胞不同，未检测到一致的淋巴细胞双标记亚群。此外，大多数c-kit阳性细胞上CD38（73%±14%，n = 4）或CD33（29%±12%，n = 5）的共表达表明它们向红细胞生成和粒细胞生成的谱系定向。
