Establishment of sample panel for detection of SARS-CoV-2 antigen and its application in development and quality evaluation of colllidal gold test cassettes

ABSTRACT

Objective To establish a sample panel for detection of severe acute respiratory symptom coronavirus 2 (SARS-CoV-2) antigen and apply to the development and quality evaluation of SARS-CoV-2 antigen colloidal gold test cassettes. Methods A sample panel for detection of SARS-CoV-2 antigen was established using 12 kinds of bulks of inactivated non-SARS-CoV-2 vaccine as negative controls, while two batches (Bl and B2) of bulks of inactivated SARS-CoV-2 vaccine (Bl, B2) and one batch (SI) of inactivated SARS-CoV-2 culture as positive controls. Bl was used as a positive control to evaluate the colloidal gold test cassettes from four manufacturers (A, B, C and D), and to monitor the development process of cassette from manufacturer A to improve its sensitivity. The negative sample panel was used to evaluate the specificity of colloidal gold test cassettes from five manufacturers (A, C, E, F and G), while positive sample panel (B2, SI and recombinant N protein) to evaluate the sensitivity. Inactivated SARS-CoV-2 culture SI was deter-mined with the commercial SARS-CoV-2 nucleic acid detection kit, and the result was compared with that by the colloidal gold test cassette from manufacturer A. Results N protein was determined as the main epitope of SARS-CoV-2 antigen by evaluation with positive control. The colloidal gold test cassettes from manufacturer A showed a sensitivity of 1 2 x 103to B1. The colloidal gold test cassettes from five manufacturers showed no cross reactions with inactivated non-SARS-CoV-2 vaccines, indicating a high specificity. The sensitivity of colloidal gold test cassette from manufacturer A was 106to B2 and 1 2 x 107to S1. However, the sensitivities of colloidal gold test cassettes from manufacturers E, F and were more than 1 103to B2 and 1 104- 1 105to SI, and that from manufacturer C was 1 104to B2 and 1 106to SI. The sensitivity of colloidal gold test cassette from manufacturer A was 100 pg/mL, while those from the other four manufacturers were 10 pg/mL, to recombinant N protein. The sensitivity of commercial nucleic acid detection kit to SI was 1 107, which was equal to that of colloidal gold test cassette from manufacturer A (1 2 x 107). Conclusion A sample panel for detection of SARS-CoV-2 antigen was successfully established, which showed high specificity and sensitivity, and might be used for the development and quality evaluation of SARS-CoV-2 antigen colloidal gold test cassettes. Copyright © 2022 Changchun Institute of Biological Products. All rights reserved.