Figure 8. Reactivity of peptides within S2 framework domain of SARS-CoV-2 spike protein against antisera from COVID-19 patients. Sera of COVID-19 patients (n = 66) and healthy blood donors (n=23) were subjected to 3 peptide fragments (FE-18, FI-22, and CK-16) from S2 domain of spike protein. The solid lines represent mean values ± SD, P<0.0001 (****). P: Patients; NI: Normal individuals.