Figure 3. Mapping the immunodominant epitopes of the SARS-CoV-2
RBD protein by Pepscan analysis against antisera from COVID-19 patients
and identification of the immunodominant peptide. (A) Sera of
COVID-19 patients (n = 66) and healthy blood donors (n=23) were
subjected to 5 pools (A to E) of overlapping peptides. Each pool
containing three 20-mer adjacent peptides that covers the entire RBD
domain of S protein. The reactivity of sera with the overlapping peptide
pools from RBD protein was determined by ELISA. (B)Identification of the immunodominant epitope among ”pool E” peptides
from RBD protein. Individual peptides (P181-200, P196-215, and P204-223)
of the positive peptide pool of RBD (pool E) were screened with plasma
samples from 25 COVID-19 patients having the highest reactivity with
this pool to determine the most reactive peptide. The solid lines
represent mean values ± SD, P<0.001 (***),P<0.0001 (****). RBD:
Receptor binding domain; P: Patients; NI: Normal individuals.