Viertlboeck Birgit C, Schweinsberg Sonja, Hanczaruk Matthias A, Schmitt Ramona, Du Pasquier Louis, Herberg Friedrich W, Göbel Thomas W
Institute for Animal Physiology, University of Munich, 80539 Munich, Germany.
Proc Natl Acad Sci U S A. 2007 Jul 10;104(28):11718-23. doi: 10.1073/pnas.0702011104. Epub 2007 Jul 2.
Fc receptors are key players of the immune system that link the fine specificity of immunoglobulins and innate effector responses. Here, we describe a nonmammalian Fcgamma receptor, CHIR-AB1, a member of the leukocyte receptor complex, that binds IgY with high affinity with its single Ig domain. It is expressed on immature and mature B lymphocytes, monocytes, macrophages, and natural killer cells and harbors motifs of activating and inhibitory Fc receptors. In the absence of FcepsilonRIgamma, CHIR-AB1 can be expressed on B cells but cross-linking does not induce intracellular calcium release. In contrast, cells expressing CHIR-AB1 and FcepsilonRIgamma are triggered to release intracellular calcium upon stimulation with heat-aggregated IgY. CHIR-AB1 thus represents a primordial Fc receptor that combines features of different mammalian counterparts.
Fc受体是免疫系统的关键参与者,它们将免疫球蛋白的精细特异性与先天性效应反应联系起来。在此,我们描述了一种非哺乳动物的Fcγ受体CHIR-AB1,它是白细胞受体复合物的成员,通过其单个Ig结构域与IgY高亲和力结合。它在未成熟和成熟的B淋巴细胞、单核细胞、巨噬细胞和自然杀伤细胞上表达,并具有激活型和抑制型Fc受体的基序。在缺乏FcεRIγ的情况下,CHIR-AB1可以在B细胞上表达,但交联不会诱导细胞内钙释放。相反,在用热聚集的IgY刺激时,表达CHIR-AB1和FcεRIγ的细胞会被触发释放细胞内钙。因此,CHIR-AB1代表了一种原始的Fc受体,它结合了不同哺乳动物对应物的特征。