AUTHOR=Nogimori Takuto , Suzuki Koichiro , Masuta Yuji , Washizaki Ayaka , Yagoto Mika , Ikeda Mami , Katayama Yuki , Kanda Hidenori , Takada Minoru , Minami Shohei , Kobayashi Takeshi , Takahama Shokichi , Yoshioka Yasuo , Yamamoto Takuya 

TITLE=Functional changes in cytotoxic CD8+ T-cell cross-reactivity against the SARS-CoV-2 Omicron variant after mRNA vaccination

JOURNAL=Frontiers in Immunology

VOLUME=13

YEAR=2023

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2022.1081047

DOI=10.3389/fimmu.2022.1081047

ISSN=1664-3224

ABSTRACT=<p>Understanding the T-cell responses involved in inhibiting COVID-19 severity is crucial for developing new therapeutic and vaccine strategies. Here, we characterized SARS-CoV-2 spike-specific CD8<sup>+</sup> T cells in vaccinees longitudinally. The BNT162b2 mRNA vaccine can induce spike-specific CD8<sup>+</sup> T cells cross-reacting to BA.1, whereas the T-cell receptor (TCR) repertoire usages decreased with time. Furthermore the mRNA vaccine induced spike-specific CD8<sup>+</sup> T cells subpopulation expressing Granzyme A (GZMA), Granzyme B (GZMB) and Perforin simultaneously in healthy donors at 4 weeks after the second vaccination. The induced subpopulation was not maintained at 12 weeks after the second vaccination. Incorporating factors that efficiently induce CD8<sup>+</sup> T cells with highly cytotoxic activity could improve future vaccine efficacy against such variants.</p>