Fernandez Z, de Arruda Rodrigues R, Torres JM, Marcon GEB, de Castro Ferreira E, de Souza VF, Sarti EFB, Bertolli GF, Araujo D, Demarchi LHF, Lichs G, Zardin MU, Gonçalves CCM, Cuenca V, Favacho A, Guilhermino J, Dos Santos LR, de Araujo FR, Silva MR. Development and validity assessment of ELISA test with recombinant chimeric protein of SARS-CoV-2.
J Immunol Methods 2023;
519:113489. [PMID:
37179011 PMCID:
PMC10174469 DOI:
10.1016/j.jim.2023.113489]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 04/07/2023] [Accepted: 05/09/2023] [Indexed: 05/15/2023]
Abstract
Serological tests developed for COVID-19 diagnostic are based on antibodies specific for SARS-CoV-2 antigens. Most of the antigens consist of a fragment or a whole amino acid sequence of the nucleocapsid or spike proteins. We evaluated a chimeric recombinant protein as an antigen in an ELISA test, using the most conserved and hydrophilic portions of the S1-subunit of the S and Nucleocapsid (N) proteins. These proteins, individually, indicated a suitable sensitivity of 93.6 and 100% and a specificity of 94.5 and 91.3%, respectively. However, our study with the chimera containing S1 and N proteins of SARS-CoV-2 suggested that the recombinant protein could better balance both the sensitivity (95.7%) and the specificity (95.5%) of the serological assay when comparing with the ELISA test using the antigens N and S1, individually. Accordingly, the chimera showed a high area under the ROC curve of 0.98 (CI 95% 0.958-1). Thus, our chimeric approach could be used to assess the natural exposure against SARS-CoV-2 virus over time, however, other tests will be necessary to better understand the behaviour of the chimera in samples from people with different vaccination doses and/or infected with different variants of the virus.
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