Molecular heterogeneity of Fc alpha receptors detected by receptor-specific monoclonal antibodies.
Molecular heterogeneity of Fc alpha receptors detected by receptor-specific monoclonal antibodies.
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DOI：
10.4049/jimmunol.148.6.1764
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发表时间：
1992-03
影响因子：
4.4
通讯作者：
R. C. Monteiro;Max D. Cooper;Hiromi Kubagawa
中科院分区：
文献类型：
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作者：
R. C. Monteiro;Max D. Cooper;Hiromi Kubagawa
从人单核细胞系中分离Fc α受体（Fc α R），并用于产生4种具有受体特异性的mAb。抗体用于鉴定表达Fc α R的白色血细胞的类型和受体分子的分子异质性。非多态性表位，以外的Fc α-结合位点，仅在血细胞的粒细胞和单核细胞/巨噬细胞谱系。通过抗体和伊加配体鉴定的分子是相对分子质量为55至75 kDa的糖蛋白。然而，一种抗体检测到Fc α R分子亚群，其特征在于相对有限的大小异质性。通过去除N-连接寡糖后分离出离散的32-和36-kDa分子种类，并通过至少部分Fc α R分子上存在O-连接碳水化合物部分的证据，揭示了复杂的糖基化模式。在生物合成研究中，所有四种抗Fc α R抗体和伊加配体结合衣霉素处理细胞中存在的单个32 kDa核心蛋白，并且特殊抗体再次识别未处理细胞中具有相对受限糖基化的分子。因此，这些抗体和天然伊加配体提供了用于确定Fc α R在系统性伊加抗体应答中的复杂结构和功能的互补试剂。
Fc alpha receptors (Fc alpha R) were isolated from a human monocytic cell line and used to raise four mAb with receptor specificity. The antibodies were used to identify the types of white blood cells that express Fc alpha R and the molecular heterogeneity of the receptor molecules. Nonpolymorphic epitopes, outside of the Fc alpha-binding site, were recognized only on blood cells of granulocyte and monocyte/macrophage lineages. The molecules identified, both by the antibodies and by the IgA ligand, were glycoproteins ranging in relative molecular mass from 55 to 75 kDa. However, one antibody detected a subpopulation of Fc alpha R molecules characterized by relatively restricted size heterogeneity. A complex glycosylation pattern was revealed by the resolution of discrete 32- and 36-kDa molecular species after removal of N-linked oligosaccharides and by evidence for O-linked carbohydrate moieties on at least a portion of the Fc alpha R molecules. In biosynthetic studies, all four anti-Fc alpha R antibodies and the IgA ligand bound a single 32-kDa core protein present in tunicamycin-treated cells, and the exceptional antibody again recognized molecules with relatively restricted glycosylation in the nontreated cells. These antibodies and native IgA ligands thus provide complementary reagents for definition of the complex structure and function of Fc alpha R in systemic IgA antibody responses.