Shaikh N, Rivera J, Hewlett B R, Stead R H, Zhu F G, Marshall J S
Department of Pathology, McMaster University, Hamilton, Ontario, Canada.
J Immunol. 1997 Apr 15;158(8):3805-12.
The activation of rodent and human mast cells can occur through the cross-linking of tetrameric IgE receptors each containing single alpha- and beta- and two gamma-subunits. However, the factors that regulate the in vivo expression of Fc epsilonRI are poorly understood. We have examined the expression of the Fc epsilonRI beta-subunit in the Nippostrongylus brasiliensis (Nb)-induced mode l of rat intestinal inflammation. We developed a double-staining technique for mast cell granules (Alcian blue) and the beta-subunit of Fc epsilonRI. The intensity of immunohistochemical staining per mast cell was quantified using an image analysis system. Jejunal and tongue mast cells of Lewis rats were visible by Alcian blue staining before Nb infection, but they expressed very low levels of beta-subunit as assessed by immunohistochemical staining. These levels were increased by day 11 postinfection and reached a maximum at day 14. Since serum IgE levels correlated well with the degree of beta-subunit expression, we investigated whether the observed enhancement of receptor expression might occur through the stabilization of receptor complexes by IgE. Therefore, Lewis rats were treated with myeloma IgE, and beta-subunit expression was examined. In both tongue and jejunal tissue, a significant rise in beta-subunit expression was observed in response to IgE injection, although levels of beta-subunit expression were not as high as those observed in Nb-infected animals. The increase in beta-subunit expression was accompanied by an increase in the amount of mast cell-associated IgE. These observations may have important implications for the regulation of IgE receptor expression during disease.
啮齿动物和人类肥大细胞的激活可通过四聚体IgE受体的交联来实现，每个四聚体IgE受体包含一个α亚基、一个β亚基和两个γ亚基。然而，调节FcεRI体内表达的因素仍知之甚少。我们研究了巴西日圆线虫（Nb）诱导的大鼠肠道炎症模型中FcεRIβ亚基的表达。我们开发了一种用于肥大细胞颗粒（阿尔辛蓝）和FcεRIβ亚基的双重染色技术。使用图像分析系统对每个肥大细胞的免疫组织化学染色强度进行定量。在Nb感染前，通过阿尔辛蓝染色可在Lewis大鼠的空肠和舌部观察到肥大细胞，但通过免疫组织化学染色评估，它们表达的β亚基水平非常低。这些水平在感染后第11天升高，并在第14天达到最高。由于血清IgE水平与β亚基表达程度密切相关，我们研究了观察到的受体表达增强是否可能通过IgE对受体复合物的稳定作用而发生。因此，给Lewis大鼠注射骨髓瘤IgE，并检测β亚基表达。在舌部和空肠组织中，均观察到β亚基表达因IgE注射而显著升高，尽管β亚基表达水平不如在Nb感染动物中观察到的高。β亚基表达的增加伴随着肥大细胞相关IgE量的增加。这些观察结果可能对疾病期间IgE受体表达的调节具有重要意义。
