Yanagihara Y, Kajiwara K, Ikizawa K, Koshio T, Okumura K, Ra C
Clinical Research Center for Allergy, National Sagamihara Hospital, Kanagawa, Japan.
J Clin Invest. 1994 Nov;94(5):2162-5. doi: 10.1172/JCI117574.
A recombinant soluble form of the alpha subunit of the human high-affinity receptor for IgE (rsFc epsilon RI alpha), one of the potent IgE-binding molecules, was tested for its ability to regulate IL-4-induced IgE synthesis by human lymphocytes. Addition of rsFc epsilon RI alpha to cultures induced a dose-dependent inhibition of the T cell-dependent and independent synthesis of IgE. The suppression of IgE synthesis was observed at the protein and the mRNA levels, and it was IgE class specific. By flow cytometry, specific binding of rsFc epsilon RI alpha was detected on surface IgE-bearing B cells as well as on U266 cells, and it was completely blocked by preincubation with IgE. rsFc epsilon RI alpha bound to the cell surface IgE could be effectively dissociated not only by a large excess of IgE, but also by an anti-rsFc epsilon RI alpha mAb that competes with IgE for the binding to rsFc epsilon RI alpha. This mAb abolished the rsFc epsilon RI alpha-mediated suppression of IgE synthesis. These data suggest that rsFc epsilon RI alpha may have a function in selectively suppressing IgE synthesis through its interaction with the membrane-bound form of IgE.
人IgE高亲和力受体α亚基的重组可溶性形式（rsFcεRIα）是一种有效的IgE结合分子，对其调节人淋巴细胞IL-4诱导的IgE合成的能力进行了测试。向培养物中添加rsFcεRIα可诱导对T细胞依赖性和非依赖性IgE合成的剂量依赖性抑制。在蛋白质和mRNA水平均观察到IgE合成的抑制，且具有IgE类别特异性。通过流式细胞术，在表面带有IgE的B细胞以及U266细胞上检测到rsFcεRIα的特异性结合，并且预先与IgE孵育可完全阻断这种结合。与细胞表面IgE结合的rsFcεRIα不仅可被大量过量的IgE有效解离，还可被与IgE竞争结合rsFcεRIα的抗rsFcεRIα单克隆抗体有效解离。这种单克隆抗体消除了rsFcεRIα介导的IgE合成抑制。这些数据表明，rsFcεRIα可能通过与膜结合形式的IgE相互作用，在选择性抑制IgE合成中发挥作用。
