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. 2022 Aug 9;11(8):e1410. doi: 10.1002/cti2.1410

Figure 1.

Figure 1

Number and magnitude of IFN‐γ CD4+ T‐cell responses directed against individual SARS‐CoV‐2 spike glycoprotein peptides of a comprehensive peptide set detected in COVID‐19 patients, COVID‐19‐naive individuals after vaccination or individuals with a combination of both. PBMCs of the participants were expanded in vitro with pools of overlapping spike peptides in the presence of anti‐CD28/anti‐CD49d antibodies and IL‐2 for 14 days before restimulation with single peptides. Cells were analysed with single‐peptide IFN‐γ ELISpot assays and validated with intracellular cytokine staining for IFN‐γ. IFN‐γ T‐cell responses mainly composed of CD4+ T‐cell responses in all groups (a). While the participants in all study groups recognised more specificities than pre‐pandemic, healthy individuals (NC), there were no significant differences in the number (b) but in the magnitude of CD4+ T‐cell responses (c) between the study groups. Within the vaccination group, spike peptides elicited stronger IFN‐γ T‐cell responses in individuals who received a booster vaccination (d). The summation of IFN‐γ T‐cell responses showed a higher IFN‐γ production in individuals with COVID‐19 than in vaccinated individuals (e). Data are expressed as mean with standard deviation. *P < 0.05; **P < 0.01; ***P < 0.001; and ****P < 0.0001.