Extended Data Fig. 3: Characterization of CoVac-1-induced immune responses.
From: A COVID-19 peptide vaccine for the induction of SARS-CoV-2 T cell immunity
(a) CoVac-1-induced long-term T cell responses assessed ex vivo or after 12-day in vitro expansion (IVE) in study participants of part I and II at day 56 and month 3 after vaccination (compared to day 28) using IFNγ ELISPOT assays. Intensity of T cell responses is depicted as calculated spot counts (mean spot count of technical replicates normalized to 500,000 cells minus the respective normalized negative control). (b) Peptide titration in ex vivo IFNγ ELISPOT assays using PBMCs from study participants (pCoVs, n = 5, day 28) or from human COVID-19 convalescent donors (HCs, n = 5) with decreasing peptide concentrations (2.5 µg mL-1 to 0.1 ng mL-1) of CoVac-1 (panel 1 and 2) or SARS-CoV-2 cross-reactive (panel 3) and SARS-CoV-2 specific (panel 4) epitope compositions (ECs). (c) Intensities of CoVac-1-induced IFNγ T cell responses assessed ex vivo in study participants of part I and part II (pCoVs, n = 24, day 28) compared to spike-specific T cell responses in healthy immunized donors after second vaccination with approved mRNA vaccines (n = 20), vector-based vaccines (n = 5), or heterologous vaccination (n = 5). (d) Anti-spike IgG antibody titers assessed on day 1 prior to vaccination and on day 28 after vaccination. Values < 0.1 were set to zero and values ≥ 1.0 were considered positive. (a, c) Box plots or combined box-line plots show median with 25th or 75th percentiles, and min/max whiskers. (a) two-sided Wilcoxon signed-rank test, (c) two-sided Mann-Whitney U-test. no, number.
