Linear epitopes of SARS-CoV-2 spike protein elicit neutralizing antibodies in COVID-19 patients

COVID-19 is caused by SARS-CoV-2. 1 , 2 By July 25, 2020, globally, 15,672,841 diagnosed cases and 638,352 deaths were reported ( https://coronavirus.jhu.edu/map.html ). 3 High titers of Spike protein (S protein)-specific antibodies are found in the blood of COVID-19 patients, especially IgG for both SARS-CoV 4 and SARS-CoV-2. 5 , 6 Because of the central role that S protein plays in the entry of the virus into the host cell, S1 and, more specifically, the RBD (receptor-binding domain) is the most targeted region for the development of COVID-19 therapeutic antibodies 7 , 8 and vaccines. 9 It is known that in addition to the RBD, other areas/epitopes of S protein may also elicit neutralizing antibodies. 10 However, antibody responses to full-length S protein have not been investigated at epitope resolution, and the capability of linear epitopes to elicit neutralizing antibodies has still not been explored.