Abstract
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-RBDN318-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-RBDN318-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-RBDN318-V510. Attachment of the antigens to the ELISA surface using a layer of anti-histidine antibodies gave equivalent resolution for both S-RBDN318-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-RBDN318-V510 may represent a cost-effective alternative to the use of structurally more complex antigens in serological COVID-19 testing.
Highlights
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causal agent of the coronavirus disease 19 (COVID-19), has infected more than 95 million people [1], at the time of this writing
We selected the region of the S-receptorbinding domain (RBD) between the residues N318 and V510 of the consensus sequence of the S protein of SARS-CoV-2
We further studied the usefulness of these two enzyme-linked immunoassays (ELISAs) versions by testing 50 samples from convalescent patients diagnosed as COVID-19 (+) by RT-qPCR
Summary
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causal agent of the coronavirus disease 19 (COVID-19), has infected more than 95 million people [1], at the time of this writing. Never before in contemporary history has humankind faced an infectious disease at this scale In response to this unprecedented challenge, a vast number of methods to screen for SARS-CoV-2 infection have been proposed [2]. These diagnostic methods are based on the identification of SARS-CoV-2 antigens, the amplification of SARSCoV-2 nucleic acids [3,4], or the detection of anti-SARS-CoV-2 antibodies [5]. The methods based on the detection of anti-SARS-CoV-2 antibodies in blood (or serological methods) are poorly suited for diagnosis of infection during the first two weeks [11] They are precisely suitable for evaluating the immune reaction to SARS-CoV-2 infection in a subject (whether symptomatic or asymptomatic) after 14 days of infection
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
