IGE BINDING AND CD38 EXPRESSION ON BASOPHIL SURFACE DURING INFANCY AND THEIR FUNCTIONAL RELEVANCE

外周血嗜碱性粒细胞表面表达FcepsilonRI。然而，其表达的调控机制在很大程度上是未知的。特别是，还没有关于FcepsilonRI在儿童时期循环中的嗜碱性粒细胞上表达的报道。在这项研究中，我们评估了新生儿和不同年龄段的儿童嗜碱性粒细胞表面的IgE结合和FcepsilonRI的表达。此外，还检测了单体IgE对FcepsilonRI的调节作用。此外，用抗IgE单抗建立了一种灵敏的酶联免疫吸附试验测定血清IgE浓度。变态反应组中嗜碱粒细胞结合的IgE显著高于正常对照组。这一差异在较年轻的年龄组中更为突出。表面结合的IgE与血清IgE浓度有很好的相关性。血清Ig E水平在100 ng/m l左右迅速升高，当血清Ig E>300 ng/m l时达到平台期，新生儿脐血中未检测到Ige结合细胞。然而，当细胞与过量的单体IgE孵育较短时间时，可迅速诱导其与IgE结合。随着孵育时间的延长，IgE结合能力进一步增强。嗜碱性粒细胞表面FcepsilonRI的表达与血清IgE水平也有很好的相关性，新生儿嗜碱性粒细胞表面FcepsilonRI的表达相对较低，但与IgE共同孵育后，其表达水平上调，这种上调依赖于新生蛋白的合成。在新生儿外周血中观察到FcepsilonRI mRNA合成的组成性合成，加入IgE后其合成水平没有明显增加，表明表面IgE受体表达的调节可能是通过转录以外的机制来实现的。

Peripheral blood basophils express FcepsilonRI on the surface. The regulatory mechanism of its expression is, however, largely unknown. In particular, there has been no report regarding the FcepsilonRI expression on circulating basophils during childhood. In this study, we evaluated IgE binding and FcepsilonRI expression on basophil surface in neonates and in children of various age groups. Furthermore, the regulation of FcepsilonRI by monomeric IgE was examined. In addition, serum IgE concentration was determined by a sensitive ELISA assay using anti-IgE monoclonal antibodies. Basophil-bound IgE was significantly high among allergics than normal controls. The difference was more prominent among younger age groups. The surface-bound IgE correlated very well with serum IgE concentrations. The level increased rapidly around 100 ng/ml of IgE and it reached a plateau when serum IgE was higher than 300 ng/ml. IgE-binding cell was undetectable within neonatal cord blood. However, IgE binding was induced rapidly when the cells were incubated with excess monomeric IgE for short period. Longer incubation resulted in further potentiation of IgE binding. FcepsilonRI expression on basophil surface also correlated well with serum IgE.FcepsilonRI expression on neonatal basophils was relatively low, but the level was upregulated when these cells were incubated with IgE.The enhancement was dependent on de novo protein synthesis. Constitutive synthesis of FcepsilonRI mRNA synthesis was observed in neonatal blood and the level was not significantly increased after the addition of IgE,indicating that a mechanism other than mRNA transcription is involved in the regulation of surface IgE receptor expression.