Functional changes in cytotoxic CD8+ T-cell cross-reactivity against the SARS-CoV-2 Omicron variant after mRNA vaccination
Takuto Nogimori, Koichiro Suzuki, Yuji Masuta, Ayaka Washizaki, Mika Yagoto, Mami Ikeda, Yuki Katayama, Hidenori Kanda, Minoru Takada, Shohei Minami, Takeshi Kobayashi, Shokichi Takahama, Yasuo Yoshioka, Takuya Yamamoto
Abstract
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 + T cells in vaccinees longitudinally. The BNT162b2 mRNA vaccine can induce spike-specific CD8 + 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 + 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 + T cells with highly cytotoxic activity could improve future vaccine efficacy against such variants.