Massive worldwide serological testing for SARS-CoV-2 is needed to determine the extent of virus exposure in a particular region, the ratio of symptomatic to asymptomatic infected persons, and the duration and extent of immunity after infection. To achieve this, the development and production of reliable and cost-effective SARS-CoV-2 antigens is critical. We report the bacterial production of the peptide S-RBD N318-V510 , which contains the receptor-binding domain of the SARS-CoV-2 spike protein (region of 193 amino acid residues from asparagine-318 to valine-510) of the SARS-CoV-2 spike protein. We purified this peptide using a straightforward approach involving bacterial lysis, his-tag-mediated affinity chromatography, and imidazole-assisted refolding. The antigen performances of S-RBD N318-V510 and a commercial full-length spike protein were compared in ELISAs. In direct ELISAs, where the antigen was directly bound to the ELISA surface, both antigens discriminated sera from non-exposed and exposed individuals. However, the discriminating resolution was better in ELISAs that used the full-spike antigen than the S-RBD N318-V510 . Attachment of the antigens to the ELISA surface using a layer of anti-histidine antibodies gave equivalent resolution for both S-RBD N318-V510 and the full-length spike protein. Results demonstrate that ELISA-functional SARS-CoV-2 antigens can be produced in bacterial cultures, and that S-RBD N318-V510 may represent a cost-effective alternative to the use of structurally more complex antigens in serological COVID-19 testing.
【저자키워드】 COVID-19, SARS-CoV-2, spike, ELISA, Receptor binding domain, Antigen, Serological testing, Escherichia coli, 【초록키워드】 Immunity, antibody, Infection, peptide, virus, Spike protein, COVID-19 testing, Asymptomatic, symptomatic, sera, S-RBD, SARS-CoV-2 antigen, serological, Critical, ELISAs, Bacterial, complex, attachment, full-length spike protein, massive, amino acid residue, bacterial cultures, approach, Result, produced, determine, the receptor-binding domain, individuals, purified, N318-V510, the SARS-CoV-2, 【제목키워드】 Test, S-RBD, Escherichia coli, exposure to, the Spike, N318-V510,