ChAdOx1 nCoV-19 vaccination generates spike-specific CD8+ T cells in aged mice.
Foster WS., Newman J., Thakur N., Spencer AJ., Davies S., Woods D., Godfrey L., Ross SH., Sharpe HJ., Richard AC., Bailey D., Lambe T., Linterman MA.
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.