Institute of Medical Virology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, U.S.A.
Cell Rep. 2018 Apr 3;23(1):90-99. doi: 10.1016/j.celrep.2018.03.027.
Immunoglobulin A (IgA) plays an important role in protecting our mucosal surfaces from viral infection, in maintaining a balance with the commensal bacterial flora, and in extending maternal immunity via breast feeding. Here, we report an additional innate immune effector function of human IgA molecules in that we demonstrate that the C-terminal tail unique to IgA molecules interferes with cell-surface attachment of influenza A and other enveloped viruses that use sialic acid as a receptor. This antiviral activity is mediated by sialic acid found in the complex N-linked glycans at position 459. Antiviral activity was observed even in the absence of classical antibody binding via the antigen binding sites. Our data, therefore, show that the C-terminal tail of IgA subtypes provides an innate line of defense against viruses that use sialic acid as a receptor and the role of neuraminidases present on these virions.
免疫球蛋白 A（IgA）在保护我们的黏膜表面免受病毒感染、维持与共生细菌菌群的平衡以及通过母乳喂养延长母体免疫力方面发挥着重要作用。在这里，我们报告了人类 IgA 分子的另一个先天免疫效应功能，即我们证明 IgA 分子所特有的 C 末端尾巴会干扰流感 A 及其他以唾液酸作为受体的包膜病毒与细胞表面的附着。这种抗病毒活性是通过位于 459 位的复杂 N 连接糖基上的唾液酸介导的。即使不存在通过抗原结合位点的经典抗体结合，也能观察到抗病毒活性。因此，我们的数据表明，IgA 亚型的 C 末端尾巴为使用唾液酸作为受体的病毒提供了先天防御，并且还表明了这些病毒粒子上神经氨酸酶的作用。
