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. 2021 Dec 17;75:103761. doi: 10.1016/j.ebiom.2021.103761

Figure 3.

Figure3

SARS-CoV-2 spike-specific CD4+ and CD8+ T cell responses. PBMCs from day -2/0 pre-vaccination (pre) and day 6-11 or 16-19 post boost (64-65 or 72-73 post prime) of n = 21 study participants were stimulated with (a) SARS-CoV-2 Wuhan-Hu-1 (Wu) spike peptide-pool and cytokine production determined by flow cytometry. Cytokine+ T cells were background-corrected for unstimulated cells. Values lower than median plus one standard deviation of pre-vaccination (0.04% for CD4, 0.01% for CD8) were considered negative. (b) PBMCs from day 0-2 pre and day 6-11 post boost (day 64-65 post prime) were stimulated with SARS-CoV-2 spike peptide pools derived from Alpha, Beta, or Gamma, or of epitopes of different infectious agents (CEFX) and compared with Wuhan-Hu-1 from (a). (c) PBMCs from day 14-19 post boost (72-73 post prime) were stimulated with a SARS-CoV-2 Delta spike peptide-pool or control (DMSO) (control) and cytokine production determined by flow cytometry. Triangle symbol indicates SARS-CoV-2 convalescent individual, where cytokine release was already high in absence of stimulation. Longitudinal T cell responses were analysed by means of a mixed linear regression model. Mann-Whitney-U test compares cytokine-positive cells at 6-11 days post boost (64-65 days after prime) upon stimulation with different SARS-CoV-2 spike variants. Unpaired t-test compares T cell responses upon control versus Delta spike-peptide treatment. *** p < 0.0001, ** p < 0.01, * p < 0.05, ns = not significant.