人肥大细胞的IgE依赖性组胺和类胰蛋白酶分泌

目的　利用人结肠组织的肥大细胞和肥大细胞激活的体外研究系统评价人肥大细胞释放类胰蛋白酶和组胺的能力及其机制。方法　经酶悬浮的人结肠肥大细胞与抗IgE抗体共同培养后记录浓度相关曲线和时间关系曲线。类胰蛋白酶用酶联免疫吸附试验的方法测量 ,而组胺则由一种以玻璃纤维为基础的荧光比色法测量。结果　抗IgE抗体可引起浓度相关性的组胺和类胰蛋白酶释放 ,最大组胺和类胰蛋白酶分泌量分别比基础分泌量超出 2 .7和 2 .5倍以上。抗IgE抗体的作用从加样后 10s开始 ,6min后达高峰并至少持续 15min。百日咳毒素和代谢抑制剂能够分别抑制抗IgE抗体引起的组胺和类胰蛋白酶释放。百日咳毒素还能够减少自发性类胰蛋白酶释放。结论　人结肠肥大细胞在受到抗IgE抗体刺激时具有平行释放类胰蛋白酶和组胺的能力 ,这个过程与肥大细胞膜G蛋白偶联受体的激活有关 ,并消耗能量。肥大细胞自发性释放组胺和类胰蛋白酶的功能可能是通过不同的机制实现的。

IgE-dependent histamine and tryptase release from human mast cells

Objective To examine the tryptase and histamine release ability of human mast cells in parallel and its potential mechanisms. Methods Enzymatically dispersed cells from human colons were co-incultured with anti-IgE, and both concentration-dependent and time course studies were performed. Tryptase release was determined by a sandwich ELISA and histamine was measured using a glass fiber-based fluorometry. Results Anti-IgE was able to induce a concentration-dependent release of histamine and tryptase from enzymatically dispersed human colon mast cells following 15 min incubation. The maximums of induced histamine and tryptase release were approximately 2.7 fold and 2.5 fold the levels of spontaneous release, respectively. The time course studies revealed that the action of anti-IgE on mast cells started at 10 second, peaked at 6 min, and lasted at least 15 min following incubation. Up to 71% histamine and 72% tryptase release induced by anti-IgE were inhibited by pretreatment of mast cells with pertussis toxin. The metabolic inhibitors were able to completely abolish the cell response to anti-IgE when they were incubated with mast cells. Moreover, pertussis toxin was able to inhibit spontaneous tryptase release from colon mast cells. Conclusion Human colon mast cells are able to release tryptase and histamine in response to anti-IgE. The process seems to be associated with the activation of a G-protein coupled receptor on the membrane of mast cells, and requires cell energy supply. Spontaneous release of histamine and tryptase from mast cells might works in different mechanisms.