Embregts Carmen W E, Verstrepen Babs, Langermans Jan A M, Böszörményi Kinga P, Sikkema Reina S, de Vries Rory D, Hoffmann Donata, Wernike Kerstin, Smit Lidwien A M, Zhao Shan, Rockx Barry, Koopmans Marion P G, Haagmans Bart L, Kuiken Thijs, GeurtsvanKessel Corine H
Department of Viroscience, Erasmus Medical Center, Rotterdam, the Netherlands.
Biomedical Primate Research Centre, Rijswijk, the Netherlands.
One Health. 2021 Dec;13:100313. doi: 10.1016/j.onehlt.2021.100313. Epub 2021 Aug 21.
Assays to measure SARS-CoV-2-specific neutralizing antibodies are important to monitor seroprevalence, to study asymptomatic infections and to reveal (intermediate) hosts. A recently developed assay, the surrogate virus-neutralization test (sVNT) is a quick and commercially available alternative to the "gold standard" virus neutralization assay using authentic virus, and does not require processing at BSL-3 level. The assay relies on the inhibition of binding of the receptor binding domain (RBD) on the spike (S) protein to human angiotensin-converting enzyme 2 (hACE2) by antibodies present in sera. As the sVNT does not require species- or isotype-specific conjugates, it can be similarly used for antibody detection in human and animal sera. In this study, we used 298 sera from PCR-confirmed COVID-19 patients and 151 sera from patients confirmed with other coronavirus or other (respiratory) infections, to evaluate the performance of the sVNT. To analyze the use of the assay in a One Health setting, we studied the presence of RBD-binding antibodies in 154 sera from nine animal species (cynomolgus and rhesus macaques, ferrets, rabbits, hamsters, cats, cattle, mink and dromedary camels). The sVNT showed a moderate to high sensitivity and a high specificity using sera from confirmed COVID-19 patients (91.3% and 100%, respectively) and animal sera (93.9% and 100%), however it lacked sensitivity to detect low titers. Significant correlations were found between the sVNT outcomes and PRNT and the Wantai total Ig and IgM ELISAs. While species-specific validation will be essential, our results show that the sVNT holds promise in detecting RBD-binding antibodies in multiple species.
检测严重急性呼吸综合征冠状病毒2（SARS-CoV-2）特异性中和抗体对于监测血清流行率、研究无症状感染以及揭示（中间）宿主至关重要。最近开发的一种检测方法，即替代病毒中和试验（sVNT），是一种快速且可商业化获得的替代方法，可替代使用活病毒的“金标准”病毒中和试验，并且不需要在生物安全3级水平进行处理。该检测方法依赖于血清中存在的抗体抑制刺突（S）蛋白上的受体结合域（RBD）与人血管紧张素转换酶2（hACE2）的结合。由于sVNT不需要物种或亚型特异性结合物，因此它同样可用于检测人和动物血清中的抗体。在本研究中，我们使用了298份经聚合酶链反应（PCR）确诊的新冠肺炎患者的血清以及151份确诊感染其他冠状病毒或其他（呼吸道）感染的患者的血清，以评估sVNT的性能。为了分析该检测方法在“同一个健康”背景下的应用，我们研究了来自9种动物（食蟹猴和恒河猴、雪貂、兔子、仓鼠、猫、牛、水貂和单峰骆驼）的154份血清中RBD结合抗体的存在情况。使用确诊新冠肺炎患者的血清（分别为91.3%和100%）和动物血清（93.9%和100%）时，sVNT显示出中等至高灵敏度和高特异性，然而它在检测低滴度抗体时缺乏灵敏度。在sVNT结果与微量中和试验（PRNT）以及万泰总免疫球蛋白（Ig）和IgM酶联免疫吸附测定（ELISA）之间发现了显著相关性。虽然物种特异性验证至关重要，但我们的结果表明，sVNT在检测多种物种中的RBD结合抗体方面具有前景。
