Raghavan M, Bjorkman P J
Division of Biology, Howard Hughes Medical Institute, California Institute of Technology, Pasadena 91125, USA.
Annu Rev Cell Dev Biol. 1996;12:181-220. doi: 10.1146/annurev.cellbio.12.1.181.
Receptors for the Fc domain of immunoglobulins play an important role in immune defense. There are two well-defined functional classes of mammalian receptors. One class of receptors transports immunoglobulins across epithelial tissues to their main sites of action. This class includes the neonatal Fc receptor (FcRn), which transports immunoglobulin G (IgG), and the polymeric immunoglobulin receptor (pIgR), which transports immunoglobulin A (IgA) and immunoglobulin M (IgM). Another class of receptors present on the surfaces of effector cells triggers various biological responses upon binding antibody-antigen complexes. Of these, the IgG receptors (Fc gamma R) and immunoglobulin E (IgE) receptors (Fc epsilon R) are the best characterized. The biological responses elicited include antibody-dependent, cell-mediated cytotoxicity, phagocytosis, release of inflammatory mediators, and regulation of lymphocyte proliferation and differentiation. We summarize the current knowledge of the structures and functions of FcRn, pIgR, and the Fc gamma R and Fc epsilon RI proteins, concentrating on the interactions of the extracellular portions of these receptors with immunoglobulins.
免疫球蛋白Fc结构域的受体在免疫防御中发挥着重要作用。哺乳动物受体有两种明确的功能类别。一类受体将免疫球蛋白跨上皮组织转运到其主要作用部位。这类受体包括转运免疫球蛋白G（IgG）的新生儿Fc受体（FcRn），以及转运免疫球蛋白A（IgA）和免疫球蛋白M（IgM）的聚合免疫球蛋白受体（pIgR）。另一类存在于效应细胞表面的受体在结合抗体-抗原复合物后触发各种生物学反应。其中，IgG受体（FcγR）和免疫球蛋白E（IgE）受体（FcεR）的特征最为明确。引发的生物学反应包括抗体依赖性细胞介导的细胞毒性、吞噬作用、炎症介质释放以及淋巴细胞增殖和分化的调节。我们总结了目前关于FcRn、pIgR以及FcγR和FcεRI蛋白的结构和功能的知识，重点关注这些受体细胞外部分与免疫球蛋白的相互作用。
