Poster Presentation Lorne Infection and Immunity 2022

Spike specific T cell mediated immunity in vaccinated and COVID-19 recovered individuals (#192)

Andrea Nguyen 1 2 , Christopher Szeto 1 2 , Demetra S.M. Chatzileontiadou 1 2 , Emma J Grant 1 2 , Dhilshan Jayasinghe 1 2 , Christian A Lobos 2 , Stephanie Gras 1 2
  1. Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
  2. Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia

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.