Figure 6. Mapping of the immunodominant epitopes on the SARS-CoV-2 NP protein by Pepscan analysis against antisera from COVID-19 patients and identification of the immunodominant epitope. (A)Sera of COVID-19 patients (n = 66) and healthy blood donors (n=23) were subjected to 9 pools (F to N) of overlapping peptides that cover the entire NP protein sequence. The reactivity of sera with the overlapping peptide pool that covers the entire sequences of the NP protein was determined by ELISA. (B) Identification of the immunodominant epitope among ”pool I” peptides from NP protein. Individual peptides (P136-155, P151-170 and P166-185) of the positive peptide pool on NP protein was screened with plasma samples from 25 COVID-19 patients to determine the most reactive peptide. The solid lines represent mean values ± SD, P<0.001 (***),P<0.0001 (****). NP: Nucleocapsid; P: Patients; NI: Normal individuals.