Okada S, Nakauchi H, Nagayoshi K, Nishikawa S, Nishikawa S, Miura Y, Suda T
Department of Medicine, Jichi Medical School, Tochigi-ken, Japan.
Blood. 1991 Oct 1;78(7):1706-12.
The proto-oncogene c-kit encodes a transmembrane tyrosine kinase receptor for stem cell factor (SCF). The c-kit/SCF signal is expected to have an important role in hematopoiesis. A monoclonal antibody (ACK-2) against the murine c-kit molecule was prepared. Flow cytometric analysis showed that the bone marrow cells that expressed the c-kit molecule (approximately 5%) were B220(B)-, TER119(erythroid)-, Thy1negative-low, and WGA+. A small number of Mac-1(macrophage)+ or Gr-1(granulocyte)+ cells were c-kit-low positive. Colony-forming unit in culture (CFU-C) and day-8 and day-12 CFU-spleen (CFU-S) existed exclusively in the c-kit-positive fraction. About 20% of the Lin(lineage)-c-kit+ cells were rhodamine-123low and this fraction contained more day-12 CFU-S than day-8 CFU-S. On the basis of these findings, murine hematopoietic stem cells were enriched with normal bone marrow cells. One of two and one of four Thy-1lowLin-WGA+c-kit+ cells were CFU-C and CFU-S, respectively. Long-term repopulating ability was investigated using B6/Ly5 congenic mice. Eight and 25 weeks after transplantation of Lin-c-kit+ cells, donor-derived cells were found in the bone marrow, spleen, thymus, and peripheral blood. In peripheral blood, T cells, B cells, and granulocyte-macrophages were derived from donor cells. Injection of ACK-2 into the irradiated mice after bone marrow transplantation decreased the numbers of day-8 and day-12 CFU-S in a dose-dependent manner. Day-8 spleen colony formation was completely suppressed by the injection of 100 micrograms ACK-2, but a small number of day-12 colonies were spared. Our data show that the c-kit molecule is expressed in primitive stem cells and plays an essential role in the early stages of hematopoiesis.
原癌基因c-kit编码一种干细胞因子（SCF）的跨膜酪氨酸激酶受体。预计c-kit/SCF信号在造血过程中起重要作用。制备了一种针对小鼠c-kit分子的单克隆抗体（ACK-2）。流式细胞术分析显示，表达c-kit分子的骨髓细胞（约5%）为B220（B）阴性、TER119（红细胞）阴性、Thy1阴性低表达且WGA阳性。少数Mac-1（巨噬细胞）阳性或Gr-1（粒细胞）阳性细胞为c-kit低阳性。培养集落形成单位（CFU-C）以及第8天和第12天的脾集落形成单位（CFU-S）仅存在于c-kit阳性部分。约20%的Lin（谱系）阴性c-kit阳性细胞罗丹明-123低表达，且该部分含有的第12天CFU-S比第8天CFU-S更多。基于这些发现，用正常骨髓细胞富集了小鼠造血干细胞。两个Thy-1低表达Lin阴性WGA阳性c-kit阳性细胞中有一个是CFU-C，四个中有一个是CFU-S。使用B6/Ly5同基因小鼠研究长期重建能力。移植Lin-c-kit阳性细胞8周和25周后，在骨髓、脾脏、胸腺和外周血中发现了供体来源的细胞。在外周血中，T细胞、B细胞和粒细胞-巨噬细胞均来源于供体细胞。骨髓移植后向受照射小鼠注射ACK-2以剂量依赖方式降低了第8天和第12天CFU-S的数量。注射100微克ACK-2可完全抑制第8天脾集落形成，但仍有少数第12天的集落存活。我们的数据表明，c-kit分子在原始干细胞中表达，在造血早期起关键作用。
