Biased N-Glycosylation Site Distribution and Acquisition across the Antibody V Region during B Cell Maturation
Biased N-Glycosylation Site Distribution and Acquisition across the Antibody V Region during B Cell Maturation
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DOI：
10.4049/jimmunol.1801622
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发表时间：
2019-04-15
影响因子：
4.4
通讯作者：
Rispens, Theo
中科院分区：
文献类型：
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作者：
Koers, Jana;Derksen, Ninotska I. L.;Rispens, Theo
Ab可在Ag特异性B细胞应答期间在其V区获得N-连接聚糖。其中，这些N-连接聚糖可影响Ag结合和Ab稳定性。此外，升高的N-连接糖基化与几种B细胞相关的病理学相关。关于V区糖基化在B细胞发育的不同阶段的模式的基本知识是稀缺的。本研究的目的是建立在幼稚和记忆B细胞亚群的Ab V区域的N-糖基化位点的模式。我们分析了通过下一代测序获得的12名健康人、8名重症肌无力患者和6名系统性红斑狼疮患者外周血和骨髓B细胞Ab V区域内N-糖基化位点的分布和获得。N-糖基化位点聚集在H和L链的CDR和DE环周围，健康供体和患者的频率相似。除H链的CDR 3外，未发现针对获得N-糖基化位点的总体选择偏倚的证据。有趣的是，与IgG 1或伊加相比，IgE和IgG 4亚群获得Fab聚糖的倾向高2倍。当表达为rmAb时，38个非胚系N-糖基化位点中的35个（92%）被占据。这些结果指向在B细胞的亲和力成熟期间N-糖基化位点获取的差异选择压力，其取决于V区域内的位置并且是同种型和亚类依赖性的。升高的Fab糖基化代表T（H）2样IgG 4/IgE应答的另一个标志。
Abs can acquire N-linked glycans in their V regions during Ag-specific B cell responses. Among others, these N-linked glycans can affect Ag binding and Ab stability. Elevated N-linked glycosylation has furthermore been associated with several B cell-associated pathologies. Basic knowledge about patterns of V region glycosylation at different stages of B cell development is scarce. The aim of the current study is to establish patterns of N-glycosylation sites in Ab V regions of naive and memory B cell subsets. We analyzed the distribution and acquisition of N-glycosylation sites within Ab V regions of peripheral blood and bone marrow B cells of 12 healthy individuals, eight myasthenia gravis patients, and six systemic lupus erythematosus patients, obtained by next-generation sequencing. N-glycosylation sites are clustered around CDRs and the DE loop for both H and L chains, with similar frequencies for healthy donors and patients. No evidence was found for an overall selection bias against acquiring an N-glycosylation site, except for the CDR3 of the H chain. Interestingly, both IgE and IgG4 subsets have a 2-fold higher propensity to acquire Fab glycans compared with IgG1 or IgA. When expressed as rmAb, 35 out of 38 (92%) nongermline N-glycosylation sites became occupied. These results point toward a differential selection pressure of N-glycosylation site acquisition during affinity maturation of B cells, which depends on the location within the V region and is isotype and subclass dependent. Elevated Fab glycosylation represents an additional hallmark of T(H)2-like IgG4/IgE responses.