High resolution linear epitope mapping of the receptor binding domain of SARS-CoV-2 spike protein in COVID-19 mRNA vaccine recipients.

Nitahara, Y.; Nakagama, Y.; Kaku, N.; Candray, K.; Michimuko, Y.; Tshibangu-Kabamba, E.; Kaneko, A.; Yamamoto, H.; Mizobata, Y.; Kakeya, H.; Yasugi, M.; Kido, Y.

The prompt rollout of the coronavirus disease (COVID-19) messenger RNA (mRNA) vaccine facilitated population immunity, which shall become more dominant than natural infection-induced immunity. At the beginning of the vaccine era, the initial epitope profile in naive individuals will be the first step to build an optimal host defense system towards vaccine-based population immunity. In this study, the high-resolution linear epitope profiles between Pfizer-BioNTech COVID-19 mRNA vaccine recipients and COVID-19 patients were delineated by using microarrays mapped with overlapping peptides of the receptor binding domain (RBD) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein. The vaccine-induced antibodies targeting RBD had broader distribution across the RBD than that induced by the natural infection. The relatively lower neutralizing antibody titers observed in vaccine-induced sera could attribute to less efficient epitope selection and maturation of the vaccine-induced humoral immunity compared to the infection-induced. Furthermore, additional mutation panel assays showed that the vaccine-induced rich epitope variety targeting the RBD may aid antibodies to escape rapid viral evolution, which could grant an advantage to the vaccine immunity.