?: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
|