Hofstaetter T, Guthöhrlein G, Kanzy E J, Zilg H, Seiler F R
Behring Inst Mitt. 1984 Nov(76):75-87.
The interaction of IgG with Fc gamma receptors on human PMN was studied by investigating the capacity of IgG and some of its fragments to mediate and inhibit, respectively, binding of immune complexes to these receptors and the subsequent activation of the cells. Fragments included Fab/Fc which is monovalent but contains the complete Fc region, Facb (divalent, C gamma 3 domains removed), Fc, pFc' (a C gamma 3 dimer) and a peptide corresponding to the greater part of one C gamma 2 domain (amino acids 278 through 333) including the carbohydrate side chains. F(ab')2 and Fab served as controls. The results indicate that human IgG interacts with human PMN Fc receptors predominantly through its C gamma 2 domains, while binding of rabbit IgG involves additional sites in C gamma 3. The C gamma 2 binding site on human IgG appears to be located between those for C1 and protein A and to contain lysine residues. For its correct exposure the C gamma 2 domains must be kept in the native conformation, in which both the hinge disulfide bridges and the carbohydrate moieties are involved. A role of the sugars in the actual binding, on the other hand, can be excluded.
通过研究IgG及其一些片段分别介导和抑制免疫复合物与这些受体结合以及随后细胞激活的能力，对人多形核白细胞（PMN）上IgG与Fcγ受体的相互作用进行了研究。片段包括单价但含有完整Fc区域的Fab/Fc、Facb（二价，Cγ3结构域去除）、Fc、pFc'（Cγ3二聚体）以及对应于一个Cγ2结构域大部分（氨基酸278至333）包括碳水化合物侧链的肽。F(ab')2和Fab用作对照。结果表明，人IgG主要通过其Cγ2结构域与人PMN Fc受体相互作用，而兔IgG的结合涉及Cγ3中的其他位点。人IgG上的Cγ2结合位点似乎位于C1和蛋白A的结合位点之间，并且含有赖氨酸残基。为了使其正确暴露，Cγ2结构域必须保持天然构象，其中铰链二硫键和碳水化合物部分都参与其中。另一方面，可以排除糖在实际结合中的作用。
