Dual ELISA using SARS-CoV-2 nucleocapsid protein produced in E. coli and CHO cells reveals epitope masking by N-glycosylation

• DOI: 10.1016/j.bbrc.2020.11.060
• Publication Date: 2020-11-20T20:36:33Z
• Authors: Airi Rump; Robert Risti; Mai-Ly Kristal; Jekaterina Reut; Vitali Syritski; Aivar Lookene; Sirje Ruutel Boud...
• Keywords: Coronavirus

Spike and nucleocapsid proteins of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2-SP, SARS-CoV-2-NP) are the main immunogenic targets for antibodies. We herein demonstrate that the glycosylation of SARS-CoV-2-NP masks some of its antibody epitopes. In many cases, this can lead to false-negative serological tests. Deglycosylation of SARS-CoV-2-NP significantly increased the number of positive tests. The glycosylation pattern analysis of this protein revealed that the putative N-linked glycosylation sites, at the amino acid positions 48 and 270, co-located with two of the main immunodominant B cell epitopes.