AZD1222 vaccination induces greater spike-specific T-cell responses following breakthrough infection
ASYMPTOMATIC SARS-COV-2 INFECTION
Spike-specific CD4+ and CD8+ T-cell responses were assessed by intracellular cytokine staining (ICS) assay following stimulation of participant PBMCs with SARS-CoV-2 spike peptide pools. At ILL-D1, vaccinees had higher frequencies of spike-specific CD4+ (AZD1222 vaccinees possess an enriched SARS-CoV-2 spike-specific T-cell response upon symptomatic SARS-CoV-2 infection compared with placebo recipients. T-cell responses from vaccinees and placebo recipients were assessed following stimulation of PBMCs with SARS-CoV-2 spike peptide pools. Frequencies of SARS-CoV-2 spike protein-specific CD4+ T cells Spike-specific T cells from responders were further assessed to determine the frequencies and proportions of individual cytokines produced. We found that vaccinees had a greater proportion of polyfunctional Th1 CD4+ T cells (i.e., T cells with the ability to secrete >2 cytokines from the panel) than placebo recipients (At ILL-D14 spike-specific T-cell frequencies and the proportion of responders were increased in both groups (Correlations between ILL-D1 T-cell and humoral responses and virologic outcomes were assessed. ILL-D1 nAb titers in vaccinees directly correlated with CD4+ (Spearman rank: 0.65; Illness visit day 1 CD8+ titers display strong negative correlations with SARS-CoV-2 virologic outcomes. Scatterplot analysis depicting the relationship between 