Altered pre-existing SARS-CoV-2-specific T cell responses in elderly individuals

• Published in: Clinical immunology communications Vol. 2; pp. 6 - 11
• Main Authors: Taira, Naoyuki, Toguchi, Sakura, Miyagi, Mio, Mori, Tomoari, Tomori, Hiroaki, Oshiro, Koichi, Tamai, Osamu, Kina, Mitsuo, Miyagi, Masatake, Tamaki, Kentaro, Collins, Mary K, Ishikawa, Hiroki
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.12.2022; The Authors. Published by Elsevier Inc; Elsevier
• Subjects: Allergy and Immunology; Short Communication
• ISSN: 2772-6134; 2772-6134
• DOI: 10.1016/j.clicom.2021.12.001

Pre-existing SARS-CoV-2-specific T cells, but not antibodies, have been detected in some unexposed individuals. This may account for some of the diversity in clinical outcomes ranging from asymptomatic infection to severe COVID-19. Although age is a risk factor for COVID-19, how age affects SARS-CoV-2-specific T cell responses remains unknown. We found that pre-existing T cell responses to specific SARS-CoV-2 proteins, Spike (S) and Nucleoprotein (N), were significantly lower in elderly donors (>70 years old) than in young donors. However, substantial pre-existing T cell responses to the viral membrane (M) protein were detected in both young and elderly donors. In contrast, young and elderly donors exhibited comparable T cell responses to S, N, and M proteins after infection with SARS-CoV-2. These data suggest that although SARS-CoV-2 infection can induce T cell responses specific to various viral antigens regardless of age, diversity of target antigen repertoire for long-lived memory T cells specific for SARS-CoV-2 may decline with age; however, memory T cell responses can be maintained by T cells reactive to specific viral proteins such as M. A better understanding of the role of pre-existing SARS-CoV-2-specific T cells that are less susceptible to age-related loss may contribute to development of more effective vaccines for elderly people.