High levels of neutrophil extracellular trap (NET) formation or NETosis and autoantibodies are related to poor prognosis and disease severity of COVID-19 patients. Human angiotensin-converting enzyme 2 (ACE2) cross-reactive anti-severe acute respiratory syndrome coronavirus 2 spike protein receptor-binding domain (SARS-CoV-2 RBD) antibodies (CR Abs) have been reported as one of the sources of anti-ACE2 autoantibodies. However, the pathological implications of CR Abs in NET formation remain unknown. In this study, we first assessed the presence of CR Abs in the sera of COVID-19 patients with different severity by serological analysis. Sera and purified IgG from CR Abs positive COVID-19 patients as well as a mouse monoclonal Ab (mAb 127) that can recognize both ACE2 and the RBD were tested for their influence on NETosis and the possible mechanisms involved were studied. An association between CR Abs levels and the severity of COVID-19 in 120 patients was found. The CR Abs-positive sera and IgG from severe COVID-19 patients and mAb 127 significantly activated human leukocytes and triggered NETosis, in the presence of RBD. This NETosis, triggered by the coexistence of CR Abs and RBD, activated thrombus-related cells but was abolished when the interaction between CR Abs and ACE2 or Fc receptors was disrupted. We also revealed that CR Abs-induced NETosis was suppressed in the presence of recombinant ACE2 or the Src family kinase inhibitor, dasatinib. Furthermore, we found that COVID-19 vaccination not only reduced COVID-19 severity but also prevented the production of CR Abs after SARS-CoV-2 infection. Our findings provide possible pathogenic effects of CR Abs in exacerbating COVID-19 by enhancing NETosis, highlighting ACE2 and dasatinib as potential treatments, and supporting the benefit of vaccination in reducing disease severity and CR Abs production in COVID-19 patients.

中文翻译：

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ACE2 交叉反应性抗 SARS-CoV-2 RBD 抗体增强了 COVID-19 患者的 NETosis

高水平的中性粒细胞胞外陷阱（NET）形成或NETosis和自身抗体与COVID-19患者的不良预后和疾病严重程度有关。据报道，人血管紧张素转换酶 2 (ACE2) 交叉反应性抗严重急性呼吸综合征冠状病毒 2 尖峰蛋白受体结合域 (SARS-CoV-2 RBD) 抗体 (CR Abs) 是抗-严重急性呼吸综合征冠状病毒 2 的来源之一。 ACE2 自身抗体。然而，CR Abs 在 NET 形成中的病理学意义仍然未知。在本研究中，我们首先通过血清学分析评估了不同严重程度的COVID-19患者血清中CR抗体的存在情况。测试了 CR Abs 阳性 COVID-19 患者的血清和纯化 IgG 以及可识别 ACE2 和 RBD 的小鼠单克隆抗体 (mAb 127)，以了解它们对 NETosis 的影响，并研究了所涉及的可能机制。在 120 名患者中发现 CR 抗体水平与 COVID-19 严重程度之间存在关联。在存在 RBD 的情况下，来自重症 COVID-19 患者的 CR Abs 阳性血清和 IgG 以及 mAb 127 显着激活人类白细胞并引发 NETosis。这种由 CR Ab 和 RBD 共存引发的 NETosis 激活了血栓相关细胞，但当 CR Ab 与 ACE2 或 Fc 受体之间的相互作用被破坏时，NETosis 被消除。我们还发现，在存在重组 ACE2 或 Src 家族激酶抑制剂达沙替尼的情况下，CR Abs 诱导的 NETosis 受到抑制。此外，我们发现 COVID-19 疫苗接种不仅可以降低 COVID-19 的严重程度，还可以阻止 SARS-CoV-2 感染后 CR 抗体的产生。我们的研究结果提供了 CR Abs 通过增强 NETosis 加剧 COVID-19 的可能致病作用，强调 ACE2 和达沙替尼作为潜在的治疗方法，并支持疫苗接种在降低 COVID-19 患者疾病严重程度和 CR Abs 产生方面的益处。