Brandt J, Briddell R A, Srour E F, Leemhuis T B, Hoffman R
Division of Hematology/Oncology, Indiana University School of Medicine, Indianapolis.
Blood. 1992 Feb 1;79(3):634-41.
To test the hypothesis that the c-kit ligand plays an important role in the regulation of early events occurring during human hematopoiesis, we determined the effect of a recombinant form of c-kit ligand, termed mast cell growth factor (MGF), on the high-proliferative potential colony-forming cell (HPP-CFC) and the cell responsible for initiating long-term hematopoiesis in vitro (LTBMIC). MGF alone did not promote HPP-CFC colony formation by CD34+ DR- CD15- marrow cells, but synergistically augmented the ability of a combination of granulocyte-monocyte colony-stimulating factor (GM-CSF) interleukin (IL)-3 and a recombinant GM-CSF/IL-3 fusion protein (FP) to promote the formation of HPP-CFC-derived colonies. MGF had a similarly profound effect on in vitro long-term hematopoiesis. Repeated additions of IL-3, GM-CSF, or FP alone to CD34+ DR- CD15- marrow cells in a stromal cell-free culture system increased cell numbers 10(3)-fold by day 56 of long-term bone marrow culture (LTBMC), while combinations of MGF with IL-3 or FP yielded 10(4)- and 10(5)-fold expansion of cell numbers. Expansion of the number of assayable colony-forming unit-granulocyte-monocyte (CFU-GM) generated during LTBMC was also markedly enhanced when MGF was added in combination with IL-3 or FP. In addition, MGF, IL-3, and FP individually led to a twofold to threefold increase in HPP-CFC numbers after 14 to 21 days of LTBMC. Furthermore, the effects of these cytokines on HPP-CFC expansion during LTBMC were additive. Throughout the LTBMC, cells receiving MGF possessed a higher cloning efficiency than those receiving IL-3, GM-CSF, or FP alone. These data indicate that the c-kit ligand synergistically interacts with a number of cytokines to directly augment the proliferative capacity of primitive human hematopoietic progenitor cells.
为了验证c-kit配体在人类造血过程中发生的早期事件调节中起重要作用这一假说，我们确定了一种重组形式的c-kit配体，即肥大细胞生长因子（MGF），对高增殖潜能集落形成细胞（HPP-CFC）以及体外启动长期造血的细胞（LTBMIC）的影响。单独的MGF不能促进CD34+ DR- CD15-骨髓细胞形成HPP-CFC集落，但能协同增强粒细胞-单核细胞集落刺激因子（GM-CSF）、白细胞介素（IL）-3和重组GM-CSF/IL-3融合蛋白（FP）组合促进HPP-CFC来源集落形成的能力。MGF对体外长期造血也有类似的显著影响。在无基质细胞培养系统中，单独向CD34+ DR- CD15-骨髓细胞重复添加IL-3、GM-CSF或FP，到长期骨髓培养（LTBMC）第56天时细胞数量增加10³倍，而MGF与IL-3或FP组合则使细胞数量分别扩增10⁴倍和10⁵倍。当MGF与IL-3或FP联合添加时，LTBMC期间产生的可检测集落形成单位-粒细胞-单核细胞（CFU-GM）数量的扩增也显著增强。此外，在LTBMC 14至21天后，MGF、IL-3和FP单独作用均使HPP-CFC数量增加两倍至三倍。此外，这些细胞因子在LTBMC期间对HPP-CFC扩增的作用是相加的。在整个LTBMC过程中，接受MGF的细胞比单独接受IL-3、GM-CSF或FP的细胞具有更高的克隆效率。这些数据表明，c-kit配体与多种细胞因子协同相互作用，直接增强原始人类造血祖细胞的增殖能力。
