Identification of transcription factor specific for human mast cells

我们研究了IL-9对血清缺失培养的CD34 +脐带血（CB）和外周血（PB）细胞中人肥大细胞发育的影响。在干细胞因子（SCF）刺激下，IL-9明显增强CD34^+ CB细胞的细胞生成。绝大多数SCF+IL-9培养的细胞在4周时胰蛋白酶呈阳性。在甲基纤维素培养的CD34^+ CB细胞中，IL-9增加了与SCF一起生长的肥大细胞集落的数量和大小。此外，在CD34+ CB细胞2周的液体培养中，SCF+IL-9引起肥大细胞集落形成细胞的排他扩增，其水平明显高于SCF单独扩增。克隆细胞培养和RT-PCR分析表明，SCF+IL-9的靶细胞是CD34^+CD38^+ CB细胞，而不是CD34^+CD38^- CB细胞。IL-9既不能增加依赖scf的后代的产生，也不能支持培养6周的肥大细胞的存活。此外，SCF和SCF+IL-9在胰蛋白酶^+细胞的外观和组胺含量方面没有差异。IL-9的添加增加了患有或不患有哮喘儿童CD34^+ PB细胞SCF生长的肥大细胞集落的数量。令人感兴趣的是，哮喘患者的肥大细胞祖细胞对SCF+IL-9的反应比正常对照组更大。综上所述，IL-9似乎是人类肥大细胞祖细胞的scf依赖性生长的有效增强剂，尤其是哮喘患者。接下来，我们研究了IL-6是否通过高亲和IgE受体（FcεRI）与IgE和抗IgE交联引发人肥大细胞组胺分泌的刺激作用。作为靶细胞，我们使用外周血来源的培养肥大细胞，因为它们的FcεRIα表达优于脐带血来源的肥大细胞。与单独用SCF孵育相比，SCF+-IL-6孵育1周增加了培养肥大细胞中ige依赖性释放和细胞内组胺含量。这些增加的幅度高于SCF+IL-4。两因子组合间FcεRIα的表达也有显著差异。在SCF存在的情况下，在fcε - ri与IgE/anti-IgE交联过程中加入IL-6不影响组胺分泌。当SCF、IL-6和IL-4一起使用时，与双因子联合使用相比，培养肥大细胞中抗ige依赖性组胺的释放进一步增加。这些结果表明，在SCF存在下，IL-6可作为人肥大细胞炎症介质的促炎性因子。少

We examined the effects of IL-9 on human mast cell development from CD34^+ cord blood (CB) and peripheral blood (PB) cells in serum-deprived cultures. IL-9 apparently enhanced cell production under stimulation with stem cell factor (SCF) from CD34^+ CB cells. A great majority of the cultured cells grown with SCF+IL-9 became positive for tryptase at 4 wk. In methylcellulose cultures of CD34^+ CB cells, IL-9 increased both the number and size of mast cell colonies grown with SCF. Furthermore, SCF+IL-9 caused an exclusive expansion of mast cell colony-forming cells in 2-wk liquid culture of CD34+ CB cells, at a level markedly greater than for SCF alone. Clonal cell cultures and RT-PCR analysis showed that the target of SCF+IL-9 were the CD34^+CD38^+ CB cells rather than the CD34^+CD38^- CB cells. IL-9 neither augmented the SCF-dependent generation of progeny nor supported the survival of 6-wk cultured mast cells. Moreover, there was no difference in the appearance of tryptase^+ cells and … More histamine content in the cultured cells between SCF and SCF+IL-9. The addition of IL-9 increased numbers of mast cell colonies grown with SCF from CD34^+ PB cells in children with or without asthma. It is of interest that mast cell progenitors of asthmatic patients responded to SCF+IL-9 to a greater extent than those of normal controls. Taken together, IL-9 appears to act as a potent enhancer for the SCF-dependent growth of mast cell progenitors in humans, particularly asthmatic patients.Next, we examined whether IL-6 exerts the stimulatory effects on the secretion of histamine from human mast cells triggered by crosslinking of the high affinity IgE receptor (FcεRI) with IgE and anti-IgE. As target cells, we used peripheral blood-derived cultured mast cells grown with SCF, because they were superior in FcεRIα expression to cord blood-derived mast cells. Incubation with SCF+-IL-6 for 1 week increased the IgE-dependent release as well as intracellular content of histamine in the cultured mast cells, as compared with the values obtained by incubation with SCF alone. The magnitude of these increases was higher than that for priming with SCF+IL-4. A striking difference was also found in the expression of FcεRIα between the two-factor combinations. The addition of IL-6 during FcεRI crosslinking with IgE/anti-IgE in the presence of SCF did not influence histamine secretion. When SCF, IL-6 and IL-4 were used together, a further increase was observed in the anti-IgE-dependent liberation of histamine from the cultured mast cells, compared with the two-factor combinations. These results suggest that IL-6 functions as a secretagogue for the inflammatory mediator of human mast cells in the presence of SCF. Less