Fig. 2: CoVac-1-induced T cell responses.
From: A COVID-19 peptide vaccine for the induction of SARS-CoV-2 T cell immunity
a–c, CoVac-1-induced T cell responses assessed ex vivo by IFNγ ELISPOT assays using peripheral blood mononuclear cells from study participants of part I (n = 12) and part II (n = 24) collected before vaccination (day 1) and at different time points after vaccination (days 7, 14, 28 and 56) or from human convalescent individuals (HCs). The intensity of T cell responses is depicted as cumulative calculated spot counts (mean spot count of technical replicates normalized to 500,000 cells minus the respective negative control) (a). The number of CoVac-1 T cell epitopes (n = 6) per participant that elicited a vaccine-induced T cell response (b). Intensities of CoVac-1-induced IFNγ T cell responses assessed ex vivo in part I and part II study participants (pCoVs; n = 24, day 28 and day 56, left y axis) compared with T cell responses detected in HCs (right y axis) against CoVac-1 vaccine peptides and previously published1,2 SARS-CoV-2-specific (spec) and cross-reactive (cross) T cell epitope compositions (ECs; CoVac-1 n = 24, cross EC n = 27, spec EC n = 26) (c). d, Frequencies of functional CoVac-1‐induced CD4+ T cells in study participants before vaccination (day 1) and at day 28 following vaccination using ex vivo intracellular cytokines (IFNγ, TNF and IL-2) and surface marker staining (CD107a). The right graph displays the proportion of samples revealing difunctional (2), trifunctional (3) or tetrafunctional (4) T cells. Pos, positive. In a–d, the box plots or combined box-line plots show the median with 25th or 75th percentiles, and minimum and maximum whiskers. In a, b, d, two-sided Wilcoxon signed-rank test was used; in c, two-sided Mann–Whitney U-test was used. Healthy adults 18–55 years of age were included in part I, and participants 56–80 years of age were included in part II. pos, positive.
