The recent outbreak of a novel Coronavirus (SARS-CoV-2) and its rapid spread across the continents has generated an urgent need for assays to detect the neutralising activity of human sera or human monoclonal antibodies against SARS-CoV-2 spike protein and to evaluate the serological immunity in humans. Since the accessibility of live virus microneutralisation (MN) assays with SARS-CoV-2 is limited and requires enhanced bio-containment, the approach based on “pseudotyping” can be considered a useful complement to other serological assays. After fully characterising lentiviral pseudotypes bearing the SARS-CoV-2 spike protein, we employed them in pseudotype-based neutralisation assays in order to profile the neutralising activity of human serum samples from an Italian sero-epidemiological study. The results obtained with pseudotype-based neutralisation assays mirrored those obtained when the same panel of sera was tested against the wild type virus, showing an evident convergence of the pseudotype-based neutralisation and MN results. The overall results lead to the conclusion that the pseudotype-based neutralisation assay is a valid alternative to using the wild-type strain, and although this system needs to be optimised and standardised, it can not only complement the classical serological methods, but also allows serological assessments to be made when other methods cannot be employed, especially in a human pandemic context.

中文翻译：

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SARS-CoV-2慢病毒假型的表征以及基于假型的中和测定与基于活病毒的微量中和测定之间的相关性。

最近爆​​发的新型冠状病毒（SARS-CoV-2）及其在各大洲的迅速传播，迫切需要进行检测人类血清或人类抗SARS-CoV-2尖峰蛋白单克隆抗体的中和活性的检测方法。评估人类的血清免疫性。由于利用SARS-CoV-2进行活病毒微中和（MN）分析的可访问性受到限制，并且需要增强的生物封闭性，因此基于“伪分型”的方法可被视为对其他血清学分析的有用补充。在充分表征携带SARS-CoV-2穗蛋白的慢病毒假型后，我们将其用于基于假型的中和测定中，以分析来自意大利血清流行病学研究的人血清样品的中和活性。使用基于假型的中和测定获得的结果与当针对野生型病毒测试同一组血清时获得的结果相似，显示了基于假型的中和和MN结果的明显收敛。总体结果得出以下结论：基于假型的中和测定是使用野生型菌株的有效替代方法，尽管该系统需要进行优化和标准化，但它不仅可以补充经典的血清学方法，而且可以当无法采用其他方法时，尤其是在人类大流行的情况下，应进行血清学评估。