Fig. 4: Spike-specific T cell responses in SARS-CoV-2 seropositive and seronegative children.
a, SARS-CoV-2-specific T cell responses in children (n = 57, red) and adults (n = 83, blue) based on SARS-CoV-2 serostatus (dark; seropositive, light; seronegative). SARS-CoV-2 serostatus was 37/20 seropositive or negative in children and 64/29 seropositive or negative in adults, respectively. The assay used IFN-γ ELISpot using pepmixes containing overlapping peptides to spike, N/M or influenza and is shown in relation to serostatus. b, The magnitude of the spike-specific cellular response was compared to that against N/M and displayed as a ratio in seropositive and seronegative adults and children, as indicated. The bars indicate the mean. Brown–Forsythe and Welch’s ANOVA with Dunnett’s T3 multiple comparisons tests were used. c, Proportions of individuals within each cohort who demonstrated a cellular response to S or N/M peptides from SARS-CoV-2. d, Cytokine concentration within supernatants from the ELISpot cultures (n = 12 children, red; n = 8 adults, blue). The bars indicate the mean ± s.d. e, hCoV-specific cellular responses showed equivalent expansion after stimulation of PBMCs from SARS-CoV-2 seronegative children with the SARS-CoV-2 S2 domain pepmix (n = 11). Cultures were stimulated for 9 d and then assessed by IFN-γ ELISpot to the pepmix of the S2 domain from SARS-CoV-2 or the Alpha (OC43 and HKU-1) or Beta (NL63 and 229E) hCoV. Expansion is shown relative to unstimulated control cultures. The lines indicate the median. f, SARS-CoV-2-specific T cell response in PBMC samples taken from children before the COVID-19 pandemic (n = 4). Dotted lines in a and f indicate pre-defined positive thresholds.
