Abstract
Effective vaccines have reduced SARS-CoV-2 morbidity and mortality;
however, the elderly remain the most at risk. Understanding how vaccines
generate protective immunity, and how these mechanisms change with age
is key for informing future vaccine design. Cytotoxic CD8+ T cells are
important for killing virally infected cells, and vaccines that induce
antigen specific CD8+ T cells in addition to humoral immunity provide an
extra layer of immune protection. This is particularly important in
cases where antibody titres are sub-optimal, as can occur in older
individuals. Here, we show that in aged mice, spike-epitope specific
CD8+ T cells are generated in comparable numbers to younger animals
after ChAdOx1 nCoV-19 vaccination, although phenotypic differences
exist. This demonstrates that ChAdOx1 nCoV-19 elicits a good CD8+ T cell
response in older bodies, but that typical age-associated features are
evident on these vaccine reactive T cells.