Fig. 3: SARS-CoV-2 mRNA vaccines induce robust lung CD8⁺ T cell responses.

Lung parenchyma T cells from female K18-hACE2 mice (N = 4 per group) at Day 56 post vaccination were investigated by in vivo injection of anti-mouse CD45 antibodies (CD45iv) prior to harvesting of lung tissue. Mice received 0.5 µg CV2CoV (ancestral, orange), 0.5 µg CV2CoV.351 (Beta, light green), 0.5 µg CV2CoV.617.2 (Delta, dark green), CV2CoV.351 + CV2CoV.617.2 (0.25 µg of each; purple) or naive (unvaccinated; blue) a CD8:CD4 ratio of lung CD45iv^- T cells. b–d Total number of CD8⁺ T_RM cells (CD45iv^-CD3⁺γδTCR^-CD8⁺CD44^highCD62L^-CD103⁺CD69⁺ T cells), CD45iv^-CXCR3⁺CD8⁺ T cells and CD45iv^-PD-1⁺CD8⁺ T cells after vaccination. e–g Frequency of CD45iv^- versus CD45iv⁺ CD8⁺ T_RM cells, CXCR3⁺CD8⁺ T cells and PD-1⁺CD8⁺ T cells after vaccination. h, i Granzyme B (GrzB⁺) production by lung CD8⁺ T cells (h) and IFNy production by CD8⁺ T cells (i) was investigated by in vitro re-stimulation of lung cells with S-peptide pools derived from ancestral SARS-CoV-2. j correlation of CD8⁺ T_RM cells and GrzB⁺ CD8⁺ T cells determined by a non-parametric spearman correlation test. a–i Scatter plots are labelled with median and interquartile range. P-values were determined by one-way ANOVA and Dunn’s multiple comparison test against the naïve group (a–d), by two-way ANOVA comparing CD45iv^- versus CD45iv⁺ (e–g), or by two-way ANOVA comparing no stimulation (−) against stimulation with S-peptide (+) (h, i). Differences were considered significant at p < 0.05 with exact p-values displayed in the figure. Source data are provided as a Source Data file.