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Vaccines (Basel)
. 2021 Jan 11;9(1):E35.
doi: 10.3390/vaccines9010035.
SARS-CoV-2 Epitope Mapping on Microarrays Highlights Strong Immune-Response to N Protein Region
Angelo Music? 1 , Roberto Frigerio 1 , Alessandro Mussida 1 , Luisa Barzon 2 , Alessandro Sinigaglia 2 , Silvia Riccetti 2 , Federico Gobbi 3 , Chiara Piubelli 3 , Greta Bergamaschi 1 , Marcella Chiari 1 , Alessandro Gori 1 , Marina Cretich 1
Affiliations
- PMID: 33440622
- DOI: 10.3390/vaccines9010035
Abstract
A workflow for rapid SARS-CoV-2 epitope discovery on peptide microarrays is herein reported. The process started with a proteome-wide screening of immunoreactivity based on the use of a high-density microarray followed by a refinement and validation phase on a restricted panel of probes using microarrays with tailored peptide immobilization through a click-based strategy. Progressively larger, independent cohorts of Covid-19 positive sera were tested in the refinement processes, leading to the identification of immunodominant regions on SARS-CoV-2 spike (S), nucleocapsid (N) protein and Orf1ab polyprotein. A summary study testing 50 serum samples highlighted an epitope of the N protein (region 155-71) providing good diagnostic performance in discriminating Covid-19 positive vs. healthy individuals. Using this epitope, 92% sensitivity and 100% specificity were reached for IgG detection in Covid-19 samples, and no cross-reactivity with common cold coronaviruses was detected. Likewise, IgM immunoreactivity in samples collected within the first month after symptoms onset showed discrimination ability. Overall, epitope 155-171 from N protein represents a promising candidate for further development and rapid implementation in serological tests.
Keywords: Covid-19; SARS-CoV-2; click chemistry; epitope mapping; peptide microarrays; serological test.