AUTHOR=Kometani Kohei , Yorimitsu Takaaki , Jo Norihide , Yamaguchi Erina , Kikuchi Osamu , Fukahori Masaru , Sawada Takeshi , Tsujimoto Yoshitaka , Sunami Ayana , Li Mengqian , Ito Takeshi , Pretemer Yann , Gao Yuxian , Hidaka Yu , Yamamoto Masaki , Kaku Natsuko , Nakagama Yu , Kido Yasutoshi , Grifoni Alba , Sette Alessandro , Nagao Miki , Morita Satoshi , Nakajima Takako E. , Muto Manabu , Hamazaki Yoko 

TITLE=Booster COVID-19 mRNA vaccination ameliorates impaired B-cell but not T-cell responses in older adults

JOURNAL=Frontiers in Immunology

VOLUME=Volume 15 - 2024

YEAR=2024

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2024.1455334

DOI=10.3389/fimmu.2024.1455334

ISSN=1664-3224

ABSTRACT=Age-associated differences in the effect of repetitive vaccination, particularly on memory T-cell and B-cell responses, remain unclear. While older adults (aged ≥65 years) exhibited enhanced IgG responses following COVID-19 mRNA booster vaccination, they produced fewer spike-specific circulating follicular helper T cells-1 than younger adults. Similarly, the cytotoxic CD8+ T-cell response remained diminished with reduced PD-1 expression even after booster vaccination compared with that in younger adults, suggesting impaired memory T-cell activation in older adults. In contrast, although B-cell responses in older adults were weaker than those in younger adults in the primary response, the responses were significantly enhanced upon booster vaccination, reaching levels comparable with that observed in younger adults. Therefore, while booster vaccination ameliorates impaired humoral immunity in older adults by efficiently stimulating memory B-cell responses, it may less effectively enhance T-cell-mediated cellular immunity. Our study provides insights for the development of effective therapeutic and vaccine strategies for the most vulnerable older population.