Omicron is the evolutionarily most distinct SARS-CoV-2 variant of concern (VOC) to date. We report that Omicron BA.1 breakthrough infection in BNT162b2-vaccinated individuals resulted in strong neutralizing activity against Omicron BA.1, BA.2 and previous SARS-CoV-2 VOCs, but not against the Omicron sublineages BA.4 and BA.5. BA.1 breakthrough infection induced a robust recall response, primarily expanding B MEM cells against epitopes shared broadly amongst variants, rather than inducing BA.1-specific B cells. The vaccination-imprinted B MEM cell pool had sufficient plasticity to be remodeled by heterologous SARS-CoV-2 spike glycoprotein exposure. While selective amplification of B MEM cells recognizing shared epitopes allows for effective neutralization of most variants that evade previously established immunity, susceptibility to escape by variants that acquire alterations at hitherto conserved sites may be heightened.

中文翻译：

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Omicron BA.1 突破性感染驱动针对保守表位的交叉变体中和和记忆 B 细胞形成

Omicron 是迄今为止进化上最独特的 SARS-CoV-2 关注变体 (VOC)。我们报告说，Omicron BA.1 在 BNT162b2 疫苗接种个体中的突破性感染导致了对 Omicron BA.1、BA.2 和以前的 SARS-CoV-2 VOC 的强烈中和活性，但对 Omicron 亚系 BA.4 和 BA.5 没有影响. BA.1 突破性感染引起强烈的回忆反应，主要是扩大 B记忆体针对表位的细胞在变体之间广泛共享，而不是诱导 BA.1 特异性 B 细胞。疫苗印迹 B记忆体细胞池具有足够的可塑性，可以通过暴露于异源 SARS-CoV-2 刺突糖蛋白进行重塑。B 的选择性扩增记忆体识别共享表位的细胞可以有效中和大多数逃避先前建立的免疫力的变体，可能会增加在迄今保守位点获得改变的变体逃脱的易感性。