Fig. 4: SARS-CoV-2-specific T cell responses are characterized by a predominant profile of IL-2 production.

a, Features of CD4⁺ and CD8⁺ T cell responses against SARS-CoV-2 proteins by ICS at 6 months. Representative flow plots of CD4⁺ (top) and CD8⁺ (bottom) T cell responses against peptide pools from spike or nonspike (aggregate of N, M, ORF3a, ORF10, NSP8 and NSP7A/b) proteins. b, Polyfunctional analysis of SARS-CoV-2-specific CD4⁺ and CD8⁺ cells at 6 months. Relative distribution of single or multiple cytokine responses in CD4⁺ (top) and CD8⁺ (bottom) T cells and pattern of coexpression of IL-2, IFN-γ, TNF and IL-4 in SARS-CoV-2-specific T cells. c, Aggregate ICS responses for CD4⁺ and CD8⁺ T cells against spike and nonspike proteins according to IFN-γ and/or IL-2 production (n = 100). The significance was determined using Wilcoxon matched-pairs signed-rank test (two-sided), *P < 0.05, **P < 0.01, ****P < 0.0001. The exact P values are: for CD4⁺ T cell and spike versus nonspike, IFN-γ⁺IL-2⁻ P = 0.6629; IFN-γ⁻IL-2⁺ P < 0.0001 and IFN-γ⁺IL-2⁺ P = 0.1536; for CD8⁺ T cells spike versus nonspike; IFN-γ⁺IL-2⁻ P = 0.0036; IFN-γ⁻IL-2⁺ P = 0.3071 and IFN-γ⁺IL-2⁺ P = 0.0336. Error bars represent s.e.m. d, Correlation of spike and nonspike responses according to IFN-γ and IL-2 production by CD4⁺ (left) and CD8⁺ (right) T cells at 6 months (n = 100). Spearman’s rank correlation (two-sided) was used to test the significance and P value and r value (correlation coefficient) are indicated for each panel.