Vaccine-induced Spike-specific T cells are multispecific and preserved against VOCs. (A) PBMCs collected on days 0 and 42 were stimulated with 7 different peptide pools covering distinct regions of the Spike protein and activation was analyzed by IFN-γ-ELISpot assay. Representative ELISpot assay is shown for 1 patient on days 0 and 42. Heatmaps indicate the percentage of the response toward a single peptide pool in proportion to the total Spike-specific response in each of the tested individuals: healthy (red) and CD19 CAR T-cell patients (blue). (B) Bar graphs show the percentage of donors (healthy, n = 7; CD19 CAR T cell, n = 8) reacting to the number of Spike peptide pools tested (total 7 distinct peptide pools). (C) Mean proportion of the response to the 7 distinct Spike peptide pools in healthy (i) and CD19 CAR-T patients (ii). (D) IFN-γ-spot forming cells (SFC) per 1 million PBMC reactive to Spike-peptide pools of the ancestral (red), Delta (blue), and Omicron (green) SARS-CoV-2 variants are shown. (E) Percentage of Spike-specific T cells reactive to the Delta (i) and Omicron (ii) SARS-CoV-2 variants is shown for all 8 patients. The pie charts indicate the mean inhibition.