Rottem M, Goff J P, Albert J P, Metcalfe D D
Mast Cell Physiology Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892.
J Immunol. 1993 Nov 1;151(9):4950-63.
Stem cell factor (SCF) is known to alter the proteoglycans, proteases, and cytokines synthesized by mast cells and to activate basophils. To determine whether SCF could also effect the ultrastructural characteristics of basophils and mast cells, we examined the ultrastructure of these Fc epsilon RI+ cells over 42 days in IL-3-dependent murine bone marrow-derived cell cultures in the presence or absence of SCF. Initial experiments revealed that the addition of SCF to IL-3-dependent cells enhanced their proliferative rate without influencing the percentage of Fc epsilon RI+ or metachromatic cells. We next isolated the Fc epsilon RI+ cells using flow cytometry. Light microscopy of these cells revealed mixed cultures of both immature and mature mast cells and basophils with mature mast cells predominating by 3 wk. One hundred to 150 Fc epsilon RI+ cells were then photographed by electron microscopy at 3, 10, 21, and in some cases, 42 days of culture, and the ultrastructure of each cells was evaluated by morphometry. Each cell was scored as a mast cell or basophil using standard criteria. Analysis of this data revealed that SCF in the presence of IL-3 promoted the development of mast cells, although a significant number of basophils were noted at day 21 but were absent by day 42. When bone marrow cells cultured in IL-3 + SCF were compared with cells cultured in IL-3 alone, a significant decrease in cell and nuclear size and granule number and size was noted in both mast cells and basophils cultured in IL-3 + SCF, and basophils and mast cells under these conditions most resemble their in vivo counterparts. Thus, SCF in the presence of IL-3 increases the ratio of mast cells to basophils and alters the ultrastructural characteristics of mast cells and basophils toward a more mature phenotype.
已知干细胞因子（SCF）可改变肥大细胞合成的蛋白聚糖、蛋白酶和细胞因子，并激活嗜碱性粒细胞。为了确定SCF是否也会影响嗜碱性粒细胞和肥大细胞的超微结构特征，我们在有或无SCF存在的情况下，对依赖白细胞介素-3（IL-3）的小鼠骨髓来源细胞培养物中的这些FcεRI⁺细胞进行了42天的超微结构检查。初步实验表明，向依赖IL-3的细胞中添加SCF可提高其增殖速率，而不影响FcεRI⁺或异染性细胞的百分比。接下来，我们使用流式细胞术分离出FcεRI⁺细胞。这些细胞的光学显微镜检查显示，培养物中既有未成熟的肥大细胞和嗜碱性粒细胞，也有成熟的肥大细胞和嗜碱性粒细胞，到3周时成熟肥大细胞占主导。然后在培养3天、10天、21天（在某些情况下为42天）时，通过电子显微镜对100至150个FcεRI⁺细胞进行拍照，并通过形态计量学评估每个细胞的超微结构。使用标准标准将每个细胞分类为肥大细胞或嗜碱性粒细胞。对这些数据的分析表明，在IL-3存在的情况下，SCF促进了肥大细胞的发育，尽管在第21天观察到大量嗜碱性粒细胞，但在第42天时已不存在。当将在IL-3 + SCF中培养的骨髓细胞与仅在IL-3中培养的细胞进行比较时，发现IL-3 + SCF中培养的肥大细胞和嗜碱性粒细胞的细胞和细胞核大小以及颗粒数量和大小均显著减小，并且在这些条件下的嗜碱性粒细胞和肥大细胞与它们的体内对应物最为相似。因此，在IL-3存在的情况下，SCF增加了肥大细胞与嗜碱性粒细胞的比例，并使肥大细胞和嗜碱性粒细胞的超微结构特征朝着更成熟的表型改变。
