Uchibayashi N, Kikutani H, Barsumian E L, Hauptmann R, Schneider F J, Schwendenwein R, Sommergruber W, Spevak W, Maurer-Fogy I, Suemura M
Institute for Molecular and Cellular Biology, Osaka University, Japan.
J Immunol. 1989 Jun 1;142(11):3901-8.
We have undertaken the production of recombinant soluble Fc epsilon receptor II (Fc epsilon RII) as a secretory protein, but not as a cleavage product of membrane-bound receptor. Several plasmid constructs containing soluble receptor sequence were prepared. Only a chimeric gene containing the sequences encoding IL-6 signal peptide and the soluble moiety of Fc epsilon RII could be expressed in Xenopus laevis oocytes and CHO cells, resulting in the secretion of soluble Fc epsilon RII. The recombinant soluble Fc epsilon RII was also produced in the yeast expression system. The NH2-terminal sequence analysis of the chimeric gene product generated by oocytes demonstrated the correct cleavage of IL-6 leader sequence by a signal peptidase. Moreover, most of CHO cell and all of the yeast-derived recombinant molecules were products identical with the native B cell-derived soluble Fc epsilon RII. These recombinant products as well as the natural soluble receptor derived from a human B cell line could bind both human IgE and two different anti-Fc epsilon RII mAb and could competitively inhibit the binding of IgE to Fc epsilon RII-expressing cells. However, the recombinant soluble Fc epsilon RII and highly purified native molecules did not display any B cell growth-promoting activity.
我们已着手生产重组可溶性Fcε受体II（FcεRII），使其作为一种分泌性蛋白，而非膜结合受体的裂解产物。制备了几种含有可溶性受体序列的质粒构建体。只有一个包含编码IL-6信号肽和FcεRII可溶性部分序列的嵌合基因能在非洲爪蟾卵母细胞和CHO细胞中表达，从而分泌出可溶性FcεRII。重组可溶性FcεRII也在酵母表达系统中产生。对卵母细胞产生的嵌合基因产物进行的NH2末端序列分析表明，IL-6前导序列被信号肽正确切割。此外，大多数CHO细胞和所有酵母来源的重组分子都是与天然B细胞来源的可溶性FcεRII相同的产物。这些重组产物以及源自人B细胞系的天然可溶性受体都能与人IgE和两种不同的抗FcεRII单克隆抗体结合，并能竞争性抑制IgE与表达FcεRII的细胞的结合。然而，重组可溶性FcεRII和高度纯化的天然分子均未显示出任何促进B细胞生长的活性。
