Published in:
01-05-2021 | SARS-CoV-2 | Original Article
Development and evaluation of a serological test for diagnosis of COVID-19 with selected recombinant spike proteins
Authors:
Pingping Zhang, Qi Gao, Tang Wang, Yuehua Ke, Fei Mo, Ruizhong Jia, Wanbing Liu, Lei Liu, Shangen Zheng, Yuzhen Liu, Luping Li, Yao Wang, Lei Xu, Kun Hao, Wei Min, Xiaoli Liu, Ruifu Yang, Shiyue Li, Changqing Lin, Yong Zhao
Published in:
European Journal of Clinical Microbiology & Infectious Diseases
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Issue 5/2021
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Abstract
Serological test is a valuable diagnostic tool for coronavirus disease 2019 (COVID-19). However, considerable improvements to these tests are needed, especially in the detection sensitivity. In this study, six recombinant nucleocapsid and spike proteins of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were prepared and evaluated, including three prokaryotic expression nucleocapsid proteins (rN, rN1, rN2) and three eukaryotic expression spike proteins (rS1, rS-RBD, rS-RBD-mFc). The recombinant proteins with the highest ELISA titers (rS1 and rS-RBD-mFc) were selected to develop a double-antigen sandwich colloidal gold immunochromatography assay (GICA) to detect total antibodies against SARS-CoV-2. The clinical evaluation results showed that the sensitivity and specificity of GICA were 92.09% (419/455) and 99.44% (706/710), respectively. Moreover, a significant number (65.63%, 21/32) of COVID-19 patients with undetectable viral RNA were correctly diagnosed by the GICA method. In conclusion, the eukaryotic expression spike proteins (rS1 and rS-RBD-mFc) are more suitable than the prokaryotic expression nucleocapsid proteins for serological diagnosis of SARS-CoV-2. The proposed GICA for detection of total antibodies could be a powerful complement to the current RNA tests for COVID-19.