Fig. 5

Vaccination with single doses of AZD1222 or BNT162b2 induced the expansion of cytotoxic effector T cells. PBMCs were isolated on day 20 after vaccination and stimulated with (stim.) or without (unstim.) spike protein-encoding mRNA (BNT162b2) for 24 h and analyzed by flow cytometry for the expression of inducible activation markers and intracellularly trapped cytokines among CD8⁺ cells. Sample sizes were n = 9 for AZD1222 and n = 15 for BNT162b2, respectively. Paired samples are illustrated by color coding. In vitro re-stimulation significantly increased CD25⁺CD137⁺ (A) and FasL expressing cells in both vaccination groups (B). INFγ–producers were increased (C) and IL-2 and IL-10 co-expressing cells were significantly reduced among AZD1222 vaccinees only (D). *p < 0.05, **p < 0.01 resulting from paired t-tests. ^#p < 0.05, ^###p < 0.001 resulting from Wilcoxon signed rank tests for matched pairs