Fig. 4

Spike-specific IFNγ-producing lymphocytes were significantly increased after vaccination with BNT162b2. PBMCs were isolated at the day of vaccination (day 0) and 20 days later. Cells were then stimulated with recombinant SARS-CoV-2 spike protein for 24 h. Subsequently, an ELISPOT assay for the detection of IFNγ-producing cells was performed. A Representative shots of spot-forming cells from individuals vaccinated with either AZD1222 (A9 and A12) or BNT162b2 (B4 and B20). PBMCs were stimulated with PMA as a positive control (bottom). B The counts of spot-forming cells from day 20 were normalized to counts from day 0. Data show the relative increase in IFNγ⁺ cells after vaccination (n = 16 for AZD1222 and n = 15 for BNT162b2). p-values result from one-sample t-tests assessing the differences of group means to the hypothetical value of 1