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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel betacoronavirus causing Coronavirus disease 2019 (COVID-19). B cell receptors (BCRs) are expressed at the surface of the B cell and are secreted as soluble antibodies. These antibodies can block viral infection by neutralizing the virus, are critical for resolution of SARS-CoV-2 infection and may be correlates of protection for COVID-19 vaccines. We have previously shown that SARS-CoV-2 immunization elicits a robust antibody response that is significantly higher in individuals who recovered from COVID-19. Moreover, recovered individuals had slower antibody decay in their levels seven months after vaccination. Here, we sequenced the BCR repertoire of individuals undergoing vaccination by SARS-CoV-2 mRNA vaccine (Pfizer, BNT162b2) with (seropositive) or without (seronegative) previous laboratory confirmed COVID-19 infection. We identified genetic differences in the BCR repertoire between groups including V gene usage, CD3R length, percentage of somatic hypermutation, and clonotype diversity. We then focused our analyses to vaccine-expanded clonotypes in both groups to further analyze the differences in BCR repertoire on candidate SARS-CoV-2-specific clonotypes. We determined the frequency of pre-existing clones present after infection that were engaged by the vaccine in the seropositive group. Moreover, in both groups we identified clonotypes that were shared among individuals that could be a result of convergent evolution. Defining the characteristics and evolution of the BCR repertoire during vaccination of individuals with different histories of viral infection will aid in understanding SARS-CoV-2 humoral response dynamics.
Fraley, Elizabeth; Khanal, Santosh; LeMaster, Cas; Pierce, Stephen; Pastinen, Tomi; and Bradley, Todd, "B Cell Receptor Repertoire Dynamics And Convergent Evolution Following Sars-Cov-2 Vaccination" (2022). Research at Children's Mercy Month 2022. 14.