ABSTRACT
There is an ongoing need of developing sensitive and specific methods for the determination of SARS-CoV-2 seroconversion. For this purpose, we have developed a multiplexed flow cytometric bead array (C19BA) that allows the identification of IgG and IgM antibodies against three immunogenic proteins simultaneously: the spike receptor-binding domain (RBD), the spike protein subunit 1 (S1) and the nucleoprotein (N). Using different cohorts of samples collected before and after the pandemic, we show that this assay is more sensitive than ELISA. The combination of three viral antigens allows for the interrogation of full seroconversion. Importantly, we have detected N-reactive antibodies in COVID-19-negative individuals. Here we present a novel immunoassay that is easily implemented and has superior potential to detect low antibody titers compared to current gold standard serology methods.
Competing Interest Statement
The authors have declared no competing interest.
Funding Statement
Support was provided by the Severo Ochoa Excellence Accreditation from MCIU (SEV-2016-0644) and the SPRI I+D COVID-19 fund (Gobierno Vasco). OM-JMM and NGAA acknowledge the Agencia Estatal de Investigacion (Spain) for grants CTQ2015-68756-R, RTI2018-101269-B-I00 and RTI2018-095700-B-I00, respectively. AP has received funding from the European Research Council (ERC) grant agreement number 804236 (Horizon 2020), and the FERO Foundation.
Author Declarations
I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.
Yes
The details of the IRB/oversight body that provided approval or exemption for the research described are given below:
All serum samples were provided by the Basque Biobank (www.biobancovasco.org) after approval from the corresponding ethics committee (CEIC-E 20-26, 1-2016). All participants in the study provided informed consent and were anonymized.
All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.
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Data Availability
All the data of this work are included within the manuscript.