The SARS-CoV-2 spike glycoprotein has 22 potential N-linked glycosylation sites per monomer that are highly conserved among diverse variants, but how individual glycans affect virus entry and neutralization of Omicron variants has not been extensively characterized. Here we compared the effects of specific glycan deletions or modifications in the Omicron BA.1 and D614G spikes on spike expression, processing, and incorporation into pseudoviruses, as well as on virus infectivity and neutralization by therapeutic antibodies. We found that loss of potential glycans at spike residues N717 and N801 each conferred a loss of pseudovirus infectivity for Omicron but not for D614G or Delta variants. This decrease in infectivity correlated with decreased spike processing and incorporation into Omicron pseudoviruses. Oligomannose-enriched Omicron pseudoviruses generated in GnTI- cells or in the presence of kifunensine were non-infectious, whereas D614G or Delta pseudoviruses generated under similar conditions remained infectious. Similarly, growth of live (authentic) SARS-CoV-2 in the presence of kifunensine resulted in a greater reduction of titers for the BA.1.1 variant than Delta or D614G variants relative to their respective, untreated controls. Finally, we found that loss of some N-glycans, including N343 and N234, increased the maximum percent neutralization by the class 3 S309 monoclonal antibody against D614G but not BA.1 variants, while these glycan deletions altered the neutralization potency of the class 1 COV2-2196 and Etesevimab monoclonal antibodies without affecting maximum percent neutralization. The maximum neutralization by some antibodies also varied with the glycan composition, with oligomannose-enriched pseudoviruses conferring the highest percent neutralization. These results highlight differences in the interactions between glycans and residues among SARS-CoV-2 variants that can affect spike expression, virus infectivity, and susceptibility of variants to antibody neutralization.

中文翻译：

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与 Omicron SARS-CoV-2 变体相比，N-聚糖修饰对祖先的尖峰表达、病毒感染性和中和敏感性的影响。

SARS-CoV-2 刺突糖蛋白每个单体有 22 个潜在的 N 连接糖基化位点，这些位点在不同变体中高度保守，但单个聚糖如何影响病毒进入和中和 Omicron 变体尚未得到广泛表征。在这里，我们比较了 Omicron BA.1 和 D614G 刺突中特定聚糖缺失或修饰对刺突表达、加工和掺入假病毒的影响，以及对病毒感染性和治疗性抗体中和的影响。我们发现，刺突残基 N717 和 N801 处潜在聚糖的丢失都会导致 Omicron 假病毒感染性丧失，但 D614G 或 Delta 变体则不会。感染性的降低与尖峰加工和掺入 Omicron 假病毒的减少相关。在 GnTI-细胞中或在 kifunensine 存在下生成的富含寡甘露糖的 Omicron 假病毒是非感染性的，而在类似条件下生成的 D614G 或 Delta 假病毒仍然具有感染性。同样，在 kifunensine 存在的情况下，活的（真正的）SARS-CoV-2 的生长导致 BA.1.1 变体的滴度比 Delta 或 D614G 变体相对于各自的未处理对照有更大的降低。最后，我们发现一些 N-聚糖（包括 N343 和 N234）的丢失增加了 3 类 S309 单克隆抗体针对 D614G 的最大中和百分比，但不会增加针对 BA.1 变体的最大中和百分比，而这些聚糖缺失改变了 1 类单克隆抗体的中和效力。 COV2-2196 和 Etesevimab 单克隆抗体不影响最大中和百分比。一些抗体的最大中和也随聚糖组成而变化，富含寡甘露糖的假病毒具有最高的中和百分比。这些结果强调了 SARS-CoV-2 变体之间聚糖和残基之间相互作用的差异，这些差异可能影响尖峰表达、病毒感染性以及变体对抗体中和的敏感性。