Figure 4.

Deconvolution of peptide pools reveals that spike specific-CD8⁺ T cells recognize 1 or 2 dominant epitopes. PBMCs from vaccinated (Vx) and convalescent (CV) donors were stimulated for 12-14 days, in the presence of low dose interleukin (IL)-2, with peptide pools followed by an overnight re-stimulation with individual peptides corresponding to each allele. (A) Percentage of TNF-α⁺IFN-γ⁺ double positive CD8⁺ T cells in donor Vx03 HLA-A*0101, donor Vx04 HLA-A*0201 and donor CV10 HLA-A*0301 after re-stimulation with High Stab peptide pool as a control (orange bar) or individual peptides (grey bars). (B) Percentage of TNF-α⁺IFN-γ⁺ double positive CD8⁺ T cells in donor Vx03 HLA-A*0101, after re-stimulation with Low Stab peptide pool as a control (blue bar) or individual peptides (grey bars). (A, B) Graphs shows mean ± standard error of the mean of technical duplicates representing one experiments. (C–F) Representative tetramer stains plots on vaccinated donors (top), convalescent donors (bottom), re-stimulated with Low Stab peptide pools (left) and High Stab peptide pools (right). (C) donor Vx03 and CV01 which are HLA-A*0101⁺ stained LTDMIAQY (LTD)-tetramer (D) donor Vx04 and CV05 which are HLA-A*0201⁺ stained with YLQPRTFLLV (YLQ)-tetramer (E) donor Vx06 and CV10 which are HLA-A*0301⁺ stained with GVYFAKSTEK (GVY)-tetramer (F) donor Vx06 and CV12 which are HLA-A*0301⁺ stained with KCYGVSPTK (KCY)-tetramer (G) Quantification of tetramer stain (double positive APC and PE) CD8⁺ T cells as in (C–F) for multiple Vx and CV donors. Graphs represent two or three independent experiments.