Peptide/HLA-E*0103 tetramer staining
Two peptides with high binding affinity S17 and S19 were selected for
construction of peptide/HLA-E tetramer labeled with PE by Epigen Biotech
(Nantong, China). The PBMCs of the SARS-CoV-2 vaccinated individuals
were stained with each PE-labeled peptide/HLA-E tetramer for 10 min, and
subsequently stained with FITC-labeled anti-human CD8 mAb (clone SK1,
Biolegend, US) and APC-labeled anti-human CD3 mAb (clone OKT3,
Biolegend, US). Approximately 300,000 cells gated on
CD3+ cells were captured. The gate for
CD8+ tetramer+ T cells was set up by
matching non-tetramer staining isotype control (BioLegend). Compensation
controls were checked regularly to avoid false-positive results and
individually determined for each experimental setup.