During the coronavirus disease-2019 (COVID-19) pandemic, severe acute respiratory syndrome-related coronavirus-2 (SARS-CoV-2) has led to the infection of millions of people and has claimed hundreds of thousands of lives. The entry of the virus into cells depends on the receptor-binding domain (RBD) of the spike (S) protein of SARS-CoV-2. Although there is currently no vaccine, it is likely that antibodies will be essential for protection. However, little is known about the human antibody response to SARS-CoV-2 1 – 5 . Here we report on 149 COVID-19-convalescent individuals. Plasma samples collected an average of 39 days after the onset of symptoms had variable half-maximal pseudovirus neutralizing titres; titres were less than 50 in 33% of samples, below 1,000 in 79% of samples and only 1% of samples had titres above 5,000. Antibody sequencing revealed the expansion of clones of RBD-specific memory B cells that expressed closely related antibodies in different individuals. Despite low plasma titres, antibodies to three distinct epitopes on the RBD neutralized the virus with half-maximal inhibitory concentrations (IC 50 values) as low as 2 ng ml −1 . In conclusion, most convalescent plasma samples obtained from individuals who recover from COVID-19 do not contain high levels of neutralizing activity. Nevertheless, rare but recurring RBD-specific antibodies with potent antiviral activity were found in all individuals tested, suggesting that a vaccine designed to elicit such antibodies could be broadly effective. Although rare, antibodies against the receptor-binding domain of SARS-CoV-2 that showed potent antiviral activity were obtained from all tested convalescent individuals, suggesting that a vaccine designed to elicit such antibodies could be broadly effective.

中文翻译：

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恢复期个体对 SARS-CoV-2 的聚合抗体反应

在 2019 年冠状病毒病 (COVID-19) 大流行期间，严重急性呼吸系统综合症相关的冠状病毒 2 (SARS-CoV-2) 已导致数百万人感染并夺去了数十万人的生命。病毒进入细胞取决于 SARS-CoV-2 的刺突 (S) 蛋白的受体结合域 (RBD)。尽管目前还没有疫苗，但抗体可能对保护至关重要。然而，人类对 SARS-CoV-2 1-5 的抗体反应知之甚少。在这里，我们报告了 149 名 COVID-19 康复者。在症状出现后平均 39 天采集的血浆样本具有可变的半最大假病毒中和滴度；33% 的样品滴度低于 50，79% 的样品滴度低于 1,000，只有 1% 的样品滴度高于 5,000。抗体测序揭示了 RBD 特异性记忆 B 细胞克隆的扩增，这些细胞在不同个体中表达密切相关的抗体。尽管血浆滴度低，但针对 RBD 上三个不同表位的抗体以低至 2 ng ml -1 的半数最大抑制浓度（IC 50 值）中和了病毒。总之，从 COVID-19 康复者身上获得的大多数恢复期血浆样本不含有高水平的中和活性。然而，在所有测试的个体中都发现了具有强效抗病毒活性的罕见但反复出现的 RBD 特异性抗体，这表明旨在引发此类抗体的疫苗可能具有广泛的有效性。虽然很少见，