AUTHOR=Frans Glynis , Dillaerts Doreen , Dehaemers Tom , Van Elslande Jan , De Leeuw Jonas , Boon Lise , Maes Wim , Callewaert Nico , Calcoen Bas , Ancheva Lina , Cockx Maaike , Geukens Nick , Arat Kusay , Derua Rita , Vermeersch Pieter , Carpentier Sebastien Christian , Bossuyt Xavier TITLE=Complementarity determining regions in SARS-CoV-2 hybrid immunity JOURNAL=Frontiers in Immunology VOLUME=14 YEAR=2023 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2023.1050037 DOI=10.3389/fimmu.2023.1050037 ISSN=1664-3224 ABSTRACT=

Pre-vaccination SARS-CoV-2 infection can boost protection elicited by COVID-19 vaccination and post-vaccination breakthrough SARS-CoV-2 infection can boost existing immunity conferred by COVID-19 vaccination. Such ‘hybrid immunity’ is effective against SARS-CoV-2 variants. In order to understand ‘hybrid immunity’ at the molecular level we studied the complementarity determining regions (CDR) of anti-RBD (receptor binding domain) antibodies isolated from individuals with ‘hybrid immunity’ as well as from ‘naive’ (not SARS-CoV-2 infected) vaccinated individuals. CDR analysis was done by liquid chromatography/mass spectrometry-mass spectrometry. Principal component analysis and partial least square differential analysis showed that COVID-19 vaccinated people share CDR profiles and that pre-vaccination SARS-CoV-2 infection or breakthrough infection further shape the CDR profile, with a CDR profile in hybrid immunity that clustered away from the CDR profile in vaccinated people without infection. Thus, our results show a CDR profile in hybrid immunity that is distinct from the vaccination-induced CDR profile.