a soluble form of the high affinity ige receptor, fc-epsilon-ri, circulates in human serum一种可溶性的ige高亲和力受体fc-epsilon-ri,在人类血清中循环.pdfVIP

A Soluble Form of the High Affinity IgE Receptor, Fc- Epsilon-RI, Circulates in Human Serum 1,2 1 1 1 1 Eleonora Dehlink , Barbara Platzer , Alexandra H. Baker , Jessica LaRosa , Michael Pardo , Peter 1 1 ´ 2 1. 1 . Dwyer , Elizabeth H. Yen , Zsolt Szepfalusi , Samuel Nurko , Edda Fiebiger * 1 Division of Gastroenterology and Nutrition, Department of Pediatrics, Harvard Medical School, Children’s Hospital Boston, Boston, Massachusetts, United States of America, 2 Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria Abstract Soluble IgE receptors are potential in vivo modulators of IgE-mediated immune responses and are thus important for our basic understanding of allergic responses. We here characterize a novel soluble version of the IgE-binding alpha-chain of Fc- epsilon-RI (sFceRI), the high affinity receptor for IgE. sFceRI immunoprecipitates as a protein of ,40 kDa and contains an intact IgE-binding site. In human serum, sFceRI is found as a soluble free IgE receptor as well as a complex with IgE. Using a newly established ELISA, we show that serum sFceRI levels correlate with serum IgE in patients with elevated IgE. We also show that serum of individuals with normal IgE levels can be found to contain high levels of sFceRI. After IgE-antigen- mediated crosslinking of surface FceRI, we detect sFceRI in the exosome-depleted, soluble fraction of cell culture supernatants. We further show that sFceRI can block binding of IgE to FceRI expressed at the cell surface. In summary,