Table_1_Pre-COVID-19 Immunity to Common Cold Human Coronaviruses Induces a Recall-Type IgG Response to SARS-CoV-2 Antigens Without Cross-Neutralisation.docx

The capacity of pre-existing immunity to human common coronaviruses (HCoV) to cross-protect against de novo COVID-19is yet unknown. In this work, we studied the sera of 175 COVID-19 patients, 76 healthy donors and 3 intravenous immunoglobulins (IVIG) batches. We found that most COVID-19 patients developed anti-SARS-CoV-2 IgG antibodies before IgM. Moreover, the capacity of their IgGs to react to beta-HCoV, was present in the early sera of most patients before the appearance of anti-SARS-CoV-2 IgG. This implied that a recall-type antibody response was generated. In comparison, the patients that mounted an anti-SARS-COV2 IgM response, prior to IgG responses had lower titres of anti-beta-HCoV IgG antibodies. This indicated that pre-existing immunity to beta-HCoV was conducive to the generation of memory type responses to SARS-COV-2. Finally, we also found that pre-COVID-19-era sera and IVIG cross-reacted with SARS-CoV-2 antigens without neutralising SARS-CoV-2 infectivity in vitro. Put together, these results indicate that whilst pre-existing immunity to HCoV is responsible for recall-type IgG responses to SARS-CoV-2, it does not lead to cross-protection against COVID-19.

人类普通冠状病毒（human common coronaviruses, HCoV）的预存免疫对新发COVID-19的交叉保护能力，目前仍未明确。本研究对175名COVID-19患者、76名健康献血者的血清样本，以及3批静脉注射免疫球蛋白（intravenous immunoglobulins, IVIG）进行了分析。研究发现，多数COVID-19患者体内抗严重急性呼吸综合征冠状病毒2型（SARS-CoV-2）免疫球蛋白G（Immunoglobulin G, IgG）抗体的产生早于免疫球蛋白M（Immunoglobulin M, IgM）抗体。此外，多数患者在血清中出现抗SARS-CoV-2 IgG抗体之前，其IgG抗体就已具备与β属冠状病毒（beta-HCoV）发生反应的能力，这提示机体产生了回忆型抗体应答。相比之下，那些先产生抗SARS-CoV-2 IgM应答、后产生IgG应答的患者，其体内抗β-HCoV IgG抗体的滴度更低，这表明针对β-HCoV的预存免疫有助于机体产生针对SARS-CoV-2的记忆型免疫应答。最后，本研究还发现，COVID-19大流行前采集的血清样本与IVIG均可与SARS-CoV-2抗原发生交叉反应，但无法在体外中和SARS-CoV-2的感染性。综合以上结果可知，尽管针对HCoV的预存免疫可介导机体产生针对SARS-CoV-2的回忆型IgG应答，但该预存免疫并不能实现对COVID-19的交叉保护。