Kirshenbaum A S, Goff J P, Kessler S W, Mican J M, Zsebo K M, Metcalfe D D
Mast Cell Physiology Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892.
J Immunol. 1992 Feb 1;148(3):772-7.
Hemopoietic stem cell factor (SCF), which is the ligand for the proto-oncogene c-kit receptor (allelic with W locus) and the product of Sl locus of the mouse, has recently been cloned. The human homologue has also been cloned, and recombinant protein (human rSCF) expressed and purified to homogeneity. To determine the effect of human rSCF in the presence or absence of human rIL-3 on human bone marrow-derived mast cells and basophils, human CD34+ pluripotent progenitor cells, highly enriched (greater than 99%) from bone marrow mononuclear cells, were cultured over agarose surfaces (interphase cultures) in the presence of human rIL-3, human rIL-3 and increasing concentrations of human rSCF, or human rSCF alone. Over 3 to 4 wk, human rSCF acted synergistically with human rIL-3 at all concentrations, producing a three- to fivefold increase in total, mast cell, and basophil numbers over human rIL-3 alone when used at 100 ng/ml. The percentage of cell types in the human rIL-3 and human rIL-3 plus human rSCF cultures, however, remained the same, with basophils constituting 18 to 35% of the final cultured cells, and mast cells 3% or less of the final cell number. In the presence of human rSCF alone, the combined total percentage of mast cells and basophils was 0 to 1.0%, the majority of cells being macrophages. Mast cells cultured in human rIL-3 plus human rSCF, but not human rIL-3 alone, were berberine sulfate positive, suggesting the presence of heparin proteoglycans within granules. Electron microscopic examination of cultures supplemented with human rIL-3 and rSCF, but not human rIL-3 alone, revealed that after 3 wk in culture, mast cell granules contained tryptase and exhibited scroll, reticular, and homogeneous patterns as seen previously in CD34+/3T3 fibroblast cocultures. Thus, CD34+ cells cultured in the presence of both human rIL-3 and rSCF give rise to cultures containing increased numbers of basophils and mast cells, with the mast cells by ultrastructural studies showing evidence of maturation although the percentages of basophils and mast cells arising in these cultures remained unchanged.
造血干细胞因子（SCF）是原癌基因c-kit受体（与W位点等位）的配体，也是小鼠Sl位点的产物，最近已被克隆。人同源物也已被克隆，并且重组蛋白（人rSCF）已表达并纯化至同质。为了确定在有或无重组人白细胞介素-3（rIL-3）的情况下人rSCF对人骨髓来源的肥大细胞和嗜碱性粒细胞的作用，将从骨髓单个核细胞中高度富集（大于99%）的人CD34+多能祖细胞在琼脂糖表面（间期培养）上培养，培养条件为单独添加人rIL-3、人rIL-3加不同浓度递增的人rSCF或单独添加人rSCF。在3至4周的时间里，人rSCF在所有浓度下均与人rIL-3协同作用，当以100 ng/ml使用时，相对于单独使用人rIL-3，总细胞数、肥大细胞数和嗜碱性粒细胞数增加了三至五倍。然而，在人rIL-3以及人rIL-3加人rSCF培养物中的细胞类型百分比保持不变，嗜碱性粒细胞占最终培养细胞的18%至35%，肥大细胞占最终细胞数的3%或更少。在仅存在人rSCF的情况下，肥大细胞和嗜碱性粒细胞的总百分比为0至1.0%，大多数细胞为巨噬细胞。在人rIL-3加人rSCF中培养的肥大细胞（而非仅在人rIL-3中培养的肥大细胞）对硫酸小檗碱呈阳性反应，表明颗粒内存在肝素蛋白聚糖。对添加了人rIL-3和rSCF（而非仅添加人rIL-3）的培养物进行电子显微镜检查发现，培养3周后，肥大细胞颗粒含有类胰蛋白酶，并呈现出如先前在CD34+/3T3成纤维细胞共培养物中所见的卷轴状、网状和均匀状模式。因此，在人rIL-3和rSCF两者存在的情况下培养的CD34+细胞会产生含有更多嗜碱性粒细胞和肥大细胞的培养物，尽管这些培养物中产生的嗜碱性粒细胞和肥大细胞的百分比保持不变，但通过超微结构研究显示肥大细胞有成熟的迹象。
