Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia.
Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia.
J Clin Virol. 2021 Jun;139:104820. doi: 10.1016/j.jcv.2021.104820. Epub 2021 Apr 10.
Neutralization tests (NT) are the gold standard for detecting and quantifying anti-SARS-CoV-2 neutralizing antibodies (NAb), but their complexity restricts them to research settings or reference laboratories. Antibodies against S protein receptor binding domain (RBD) have been shown to confer a neutralizing activity against SARS-CoV-2. Assays quantitatively measuring anti-S1-RBD-SARS-CoV-2 antibodies could be of great value for NAb screening of potential donors for convalescent-phase plasma therapy, assessing natural or vaccine-induced immunity, stratifying individuals for vaccine receipt, and documenting vaccine response.
Elecsys Anti-SARS-CoV-2 S (Elecsys-S), a high-throughput automated electrochemiluminescence double-antigen sandwich immunoassay for quantitative measurement of pan-anti-S1-RBD-SARS-CoV-2 antibodies, was evaluated against NT on 357 patients with PCR-confirmed SARS-CoV-2 infection. NT was performed in a BSL-3 laboratory using a Slovenian SARS-CoV-2 isolate; the NT titer ≥1:20 was considered positive.
Elecsys-S detected pan-anti-S1-RBD-SARS-CoV-2 antibodies in 352/357 (98.6 %) samples. NAb were identified by NT in 257/357 (72 %) samples. The Elecsys-S/NT agreement was moderate (Cohen's kappa 0.56). High NT titer antibodies (≥1:160) were detected in 106/357 (30 %) samples. Elecsys-S's pan-anti-S1-RBD-SARS-CoV-2 antibody concentrations correlated with individual NT titer categories (the lowest concentrations were identified in NT-negative samples and the highest in samples with NT titer 1:1,280), and the Elecsys-S cutoff value for reasonable prediction of NAb generated after natural infection was established (133 BAU/mL).
Although NT should remain the gold standard for assessing candidates for convalescent-phase plasma donors, selected commercial anti-SARS-CoV-2 assays with optimized cutoff, like Elecsys-S, could be used for rapid, automated, and large-scale screening of individuals with clinically relevant NAb levels as suitable donors.
中和试验（NT）是检测和定量抗 SARS-CoV-2 中和抗体（NAb）的金标准，但由于其复杂性，限制了其在研究环境或参考实验室中的应用。针对 S 蛋白受体结合域（RBD）的抗体已被证明具有针对 SARS-CoV-2 的中和活性。定量测量抗 S1-RBD-SARS-CoV-2 抗体的测定法对于恢复期血浆疗法的潜在供体的 NAb 筛选、评估自然或疫苗诱导的免疫、为疫苗接种个体分层以及记录疫苗反应具有重要价值。
Elecsys Anti-SARS-CoV-2 S（Elecsys-S）是一种高通量自动化电化学发光双抗原夹心免疫分析法，用于定量测量 pan-anti-S1-RBD-SARS-CoV-2 抗体，对 357 名经 PCR 确认的 SARS-CoV-2 感染患者的 NT 进行了评估。NT 在 BSL-3 实验室中使用斯洛文尼亚 SARS-CoV-2 分离株进行；NT 滴度≥1:20 被认为是阳性。
Elecsys-S 在 357 个样本中的 352 个（98.6%）样本中检测到 pan-anti-S1-RBD-SARS-CoV-2 抗体。在 357 个样本中有 257 个（72%）样本通过 NT 识别出 NAb。Elecsys-S/NT 的一致性为中度（Cohen's kappa 0.56）。在 106 个（30%）样本中检测到高 NT 滴度抗体（≥1:160）。Elecsys-S 的 pan-anti-S1-RBD-SARS-CoV-2 抗体浓度与个体 NT 滴度类别相关（NT 阴性样本的浓度最低，NT 滴度 1:1,280 的样本的浓度最高），并且确定了用于预测自然感染后产生的 NAb 的 Elecsys-S 截断值（133 BAU/mL）。
尽管 NT 仍然是评估恢复期血浆供体候选人的金标准，但像 Elecsys-S 这样的具有优化截断值的选定商业抗 SARS-CoV-2 测定法可以用于快速、自动化和大规模筛选具有临床相关 NAb 水平的个体，作为合适的供体。
