Figure 2.

Stimulation with High Stab peptide pools enriches for spike-specific-CD8⁺T cells in a vaccinated cohort. PBMCs from vaccinated (Vx) donors were stimulated for 12-14 days in the presence of low dose interleukin (IL)-2, with High Stab or Low Stab peptide pools followed by an overnight re-stimulation with the same peptide pools. Surface and intracellular cytokine stain was performed, and cells were analyzed by flow cytometry (A) Representative plot of interferon (IFN)-γ and tumor necrosis factor (TNF)-α on CD8⁺T cells after Low Stab peptide stimulation (left) or High Stab peptide stimulation (right), with (top) or without (below) re-stimulation. (B) Percentage of IFN-γ and TNF-α double positive CD8⁺ T cells on HLA-A*0101, -A*0201, -A*0301 donors. Samples stimulated with Low Stab peptide pools are depicted in blue and samples stimulated with High Stab peptide pools are depicted in orange. Graphs shows mean ± standard error of the mean of technical duplicates representing three independent experiments. (C) Representative plot of activation marker CD137 and degranulation marker CD107a on CD8⁺T cells after Low Stab peptide stimulation (left) or High Stab peptide stimulation (right), with (top) or without (below) re-stimulation. (D) Correlation between CD137⁺CD107a⁺ double positive and TNF-α⁺IFN-γ⁺ double positive CD8⁺ T cells in all donors analyzed regardless of the HLA typing.