荷兰阿姆斯特丹大学Gestur Vidarsson小组发现，岩藻糖基化IgG与COVID-19严重程度相关。相关论文于2020年12月23日在线发表在《科学》杂志上。

研究人员发现，岩藻糖基化的IgG（约占人类总IgG的6％）是针对包膜病毒而形成的，但通常不针对其他抗原。这可介导更强的Fc受体（FcγRIIIa）反应，但也会放大细胞因子风暴和免疫产生的病理。重症COVID-19患者，而非轻症患者，具有较高水平的SARS-CoV-2岩藻糖基化IgG抗体，从而放大了促炎性细胞因子的释放和急性期反应。因此，抗体糖基化在包膜病毒（包括COVID-19）的免疫反应中起关键作用。

据了解，IgG抗体对于防御入侵的病原体至关重要。IgG功能必需的IgG-Fc尾巴中高度保守的N-连接聚糖在人体内显示出可变的组成。岩藻糖基化的IgG变体通过FcγRIIIa增强了活性，并已用于抗癌治疗性抗体中。

附：英文原文

Title: Afucosylated IgG characterizes enveloped viral responses and correlates with COVID-19 severity

Author: Mads Delbo Larsen, Erik L. de Graaf, Myrthe E. Sonneveld, H. Rosina Plomp, Jan Nouta, Willianne Hoepel, Hung-Jen Chen, Federica Linty, Remco Visser, Maximilian Brinkhaus, Toni uti, Steven W. de Taeye, Arthur E. H. Bentlage, Suvi Toivonen, Carolien A. M. Koeleman, Susanna Sainio, Neeltje A. Kootstra, Philip J.M. Brouwer, Chiara Elisabeth Geyer, Ninotska I. L. Derksen, Gertjan Wolbink, Menno de Winther, Rogier W. Sanders, Marit J. van Gils, Sanne de Bruin, Alexander P. J. Vlaar, Amsterdam UMC COVID- biobank study group, Theo Rispens, Jeroen den Dunnen, Hans L. Zaaijer, Manfred Wuhrer, C. Ellen van der Schoot, Gestur Vidarsson

Issue&Volume: 2020/12/23

Abstract: IgG antibodies are crucial for protection against invading pathogens. A highly conserved N-linked glycan within the IgG-Fc tail, essential for IgG function, shows variable composition in humans. Afucosylated IgG variants are already used in anti-cancer therapeutic antibodies for their elevated activity through Fc receptors (FcγRIIIa). Here, we report that afucosylated IgG (~6% of total IgG in humans) are specifically formed against enveloped viruses but generally not against other antigens. This mediates stronger FcγRIIIa responses, but also amplifies brewing cytokine storms and immune-mediated pathologies. Critically ill COVID-19 patients, but not those with mild symptoms, had high levels of afucosylated IgG antibodies against SARS-CoV-2, amplifying pro-inflammatory cytokine release and acute phase responses. Thus, antibody glycosylation plays a critical role in immune responses to enveloped viruses, including COVID-19.

DOI: 10.1126/science.abc8378

Source: https://science.sciencemag.org/content/early/2020/12/22/science.abc8378