T cell and antibody kinetics delineate SARS-CoV-2 peptides mediating long-term immune responses in COVID-19 convalescent individuals.

T cells keep it up: A major focus of investigation for researches studying severe acute respiratory syndrome coronavirus 2 (SARS CoV-2) is how long immunological memory persists after infection. In this study, Bilich et al. specifically explored the kinetics of SARS-CoV-2–specific T cell responses in two cohorts of patients up to 6 months after infection. The authors found that, whereas antibody responses wane, T cell responses to SARS-CoV-2 antigens remain consistent or increase over time. These findings are supported by other studies and suggest that vaccines that elicit T cell responses may be essential for providing long-term protection against SARS-CoV-2 infection. Long-term immunological memory to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is crucial for the development of population-level immunity, which is the aim of vaccination approaches. Reports on rapidly decreasing antibody titers have led to questions regarding the efficacy of humoral immunity alone. The relevance of T cell memory after coronavirus disease 2019 (COVID-19) remains unclear. Here, we investigated SARS-CoV-2 antibody and T cell responses in matched samples of COVID-19 convalescent individuals up to 6 months after infection. Longitudinal analysis revealed decreasing and stable spike- and nucleocapsid-specific antibody responses, respectively. In contrast, functional T cell responses remained robust, and even increased, in both frequency and intensity. Single peptide mapping of T cell diversity over time identified open reading frame–independent, dominant T cell epitopes mediating long-term SARS-CoV-2 T cell responses. Identification of these epitopes may be fundamental for COVID-19 vaccine design. [ABSTRACT FROM AUTHOR]