Impaired Priming of SARS-CoV-2-Specific Naive CD8 + T Cells in Older Subjects.

Advanced age is associated with severe symptoms and death upon SARS-CoV-2 infection. Virus-specific CD8 ⁺ T-cell responses have shown to be protective toward critical COVID-19 manifestations, suggesting that suboptimal cellular immunity may contribute to the age-pattern of the disease. The induction of a CD8 ⁺ T-cell response against an emerging pathogen like SARS-CoV-2 relies on the activation of naive T cells. To investigate whether the primary CD8 ⁺ T-cell response against this virus is defective in advanced age, we used an in vitro approach to prime SARS-CoV-2-specific naive CD8 ⁺ T cells from healthy, unexposed donors of different age groups. Compared to younger adults, older individuals display a poor SARS-CoV-2-specific T-cell priming capacity in terms of both magnitude and quality of the response. In addition, older subjects recognize a lower number of epitopes. Our results implicate that immune aging is associated with altered primary SARS-CoV-2-specific CD8 ⁺ T-cell responses.
Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
(Copyright © 2021 Gallerani, Proietto, Dallan, Campagnaro, Pacifico, Albanese, Marzola, Marconi, Caputo, Appay, Gavioli and Nicoli.)