Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the ongoing coronavirus disease 2019 (COVID-19) pandemic. With the increasingly high uptake of the vaccines available, efforts are being made worldwide to understand and compare the immune response to SARS-CoV-2 in vaccinated and COVID-19 recovered individuals including the impact of T cell immunity.
We assessed the ex-vivo T cell response to Spike-derived peptides in HLA-A*02:01+ vaccinated and COVID-19 recovered individuals and identified novel epitopes, as well as the difference in response between the two cohorts of donors. In vitro peptide stimulation revealed T cell-mediated cross-reactivity with variant of concern (VOC) derived peptides, as well as the TCR repertoire of selected spike epitopes. In addition, we have also characterised HLA-A*02:01 presentation of spike-derived epitopes and their recognition by T cell receptors at the atomic level, their affinity for VOC epitope and their stability.
Our study contributes to a deeper understanding of the T cell mediated immunity from SARS-CoV-2 infection and COVID-19 vaccines, their key differences, that could be exploited to design universal vaccines against VOC.