The emergence of SARS-CoV-2 variants of concern (VOC) is driven by mutations that mediate escape from neutralizing antibodies. There is also evidence that mutations can cause loss of T-cell epitopes. However, studies on viral escape from T-cell immunity have been hampered by uncertain estimates of epitope prevalence. Here, we map and quantify CD8 T-cell responses to SARS-CoV-2-specific minimal epitopes in blood drawn April-June 2020 from 83 COVID-19 convalescents. Among 37 HLA-ligands eluted from five prevalent alleles and an additional 86 predicted binders, we identify 29 epitopes with an immunoprevalence ranging from 3-100% among individuals expressing the relevant HLA-allele. Mutations in VOCs are reported in 10.3% of the epitopes, while 20.6% of the non-immunogenic peptides are mutated in VOCs. The nine most prevalent epitopes are conserved in VOCs. Thus, comprehensive mapping of epitope prevalence does not provide evidence that mutations in VOCs are driven by escape of T-cell immunity.

Fuente: Cell Reports
Available online 9 January 2023, 111995