AUTHOR=Ahmed Mohamed Ibraheem Mahmoud , Diepers Paulina , Janke Christian , Plank Michael , Eser Tabea M. , Rubio-Acero Raquel , Fuchs Anna , Baranov Olga , Castelletti Noemi , Kroidl Inge , Olbrich Laura , Bauer Bernadette , Wang Danni , Prelog Martina , Liese Johannes G. , Reinkemeyer Christina , Hoelscher Michael , Steininger Philipp , Überla Klaus , Wieser Andreas , Geldmacher Christof TITLE=Enhanced Spike-specific, but attenuated Nucleocapsid-specific T cell responses upon SARS-CoV-2 breakthrough versus non-breakthrough infections JOURNAL=Frontiers in Immunology VOLUME=13 YEAR=2022 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2022.1026473 DOI=10.3389/fimmu.2022.1026473 ISSN=1664-3224 ABSTRACT=

SARS-CoV-2 vaccine breakthrough infections frequently occurred even before the emergence of Omicron variants. Yet, relatively little is known about the impact of vaccination on SARS-CoV-2-specific T cell and antibody response dynamics upon breakthrough infection. We have therefore studied the dynamics of CD4 and CD8 T cells targeting the vaccine-encoded Spike and the non-encoded Nucleocapsid antigens during breakthrough infections (BTI, n=24) and in unvaccinated control infections (non-BTI, n=30). Subjects with vaccine breakthrough infection had significantly higher CD4 and CD8 T cell responses targeting the vaccine-encoded Spike during the first and third/fourth week after PCR diagnosis compared to non-vaccinated controls, respectively. In contrast, CD4 T cells targeting the non-vaccine encoded Nucleocapsid antigen were of significantly lower magnitude in BTI as compared to non-BTI. Hence, previous vaccination was linked to enhanced T cell responses targeting the vaccine-encoded Spike antigen, while responses against the non-vaccine encoded Nucleocapsid antigen were significantly attenuated.