Antibodies predating infection Immunological memory after infection with seasonal human coronaviruses (hCoVs) may potentially contribute to cross-protection against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Ng et al. report that in a cohort of 350 SARS-CoV-2–uninfected individuals, a small proportion had circulating immunoglobulin G (IgG) antibodies that could cross-react with the S2 subunit of the SARS-CoV-2 spike protein (see the Perspective by Guthmiller and Wilson). By contrast, COVID-19 patients generated IgA, IgG, and IgM antibodies that recognized both the S1 and S2 subunits. The anti-S2 antibodies from SARS-CoV-2–uninfected patients showed specific neutralizing activity against both SARS-CoV-2 and SARS-CoV-2 S pseudotypes. A much higher percentage of SARS-CoV-2–uninfected children and adolescents were positive for these antibodies compared with adults. This pattern may be due to the fact that children and adolescents generally have higher hCoV infection rates and a more diverse antibody repertoire, which may explain the age distribution of COVID-19 susceptibility. Science, this issue p. 1339; see also p. 1272 SARS-CoV-2 neutralizing antibodies can be found in some uninfected individuals—predominantly children and adolescents. Zoonotic introduction of novel coronaviruses may encounter preexisting immunity in humans. Using diverse assays for antibodies recognizing SARS-CoV-2 proteins, we detected preexisting humoral immunity. SARS-CoV-2 spike glycoprotein (S)–reactive antibodies were detectable using a flow cytometry–based method in SARS-CoV-2–uninfected individuals and were particularly prevalent in children and adolescents. They were predominantly of the immunoglobulin G (IgG) class and targeted the S2 subunit. By contrast, SARS-CoV-2 infection induced higher titers of SARS-CoV-2 S–reactive IgG antibodies targeting both the S1 and S2 subunits, and concomitant IgM and IgA antibodies, lasting throughout the observation period. SARS-CoV-2–uninfected donor sera exhibited specific neutralizing activity against SARS-CoV-2 and SARS-CoV-2 S pseudotypes. Distinguishing preexisting and de novo immunity will be critical for our understanding of susceptibility to and the natural course of SARS-CoV-2 infection.

中文翻译：

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人类对 SARS-CoV-2 已有的体液免疫和从头体液免疫


感染前的抗体感染季节性人类冠状病毒（hCoV）后的免疫记忆可能有助于针对严重急性呼吸综合征冠状病毒2（SARS-CoV-2）的交叉保护。吴等人。报告称，在 350 名未感染 SARS-CoV-2 的个体中，一小部分人体内有循环免疫球蛋白 G (IgG) 抗体，可以与 SARS-CoV-2 刺突蛋白的 S2 亚基发生交叉反应（参见古斯米勒和威尔逊）。相比之下，COVID-19 患者产生的 IgA、IgG 和 IgM 抗体可识别 S1 和 S2 亚基。来自未感染 SARS-CoV-2 的患者的抗 S2 抗体对 SARS-CoV-2 和 SARS-CoV-2 S 假型病毒均表现出特异性中和活性。与成人相比，未感染 SARS-CoV-2 的儿童和青少年中这些抗体呈阳性的比例要高得多。这种模式可能是由于儿童和青少年普遍具有较高的 hCoV 感染率和更多样化的抗体库，这可能解释了 COVID-19 易感性的年龄分布。科学，本期第 14 页。第1339章另见 p.第1272章 SARS-CoV-2中和抗体可以在一些未感染的个体（主要是儿童和青少年）中发现。新型冠状病毒的人畜共患传入可能会遇到人类预先存在的免疫力。通过对识别 SARS-CoV-2 蛋白的抗体进行多种检测，我们检测到了预先存在的体液免疫。使用基于流式细胞术的方法可在未感染 SARS-CoV-2 的个体中检测到 SARS-CoV-2 刺突糖蛋白 (S) 反应性抗体，并且在儿童和青少年中尤其普遍。它们主要属于免疫球蛋白 G (IgG) 类，并针对 S2 亚基。 相比之下，SARS-CoV-2 感染诱导了针对 S1 和 S2 亚基的 SARS-CoV-2 S 反应性 IgG 抗体滴度更高，以及伴随的 IgM 和 IgA 抗体，并在整个观察期间持续。 SARS-CoV-2 未感染的供体血清对 SARS-CoV-2 和 SARS-CoV-2 S 假型表现出特异性中和活性。区分预先存在的免疫和新生免疫对于我们了解 SARS-CoV-2 感染的易感性和自然病程至关重要。