Fig. 5: Cell-extrinsic signals induce T-cell aging.

a Correlogram showing for the indicated SLO of old mice the correlations between Foxo1 expression by a given subset of T cells and its expression by the others (upper panel). Blue colors indicate positive correlations, while red colors indicate negative correlations. The darker the color, the more significant the correlation. Correlation curves are presented for the spleen (lower panel). b Diagram illustrating the experimental model. c Relative Foxo1 MFIs for CD4_N, CD4_M and CD4_R donor cells recovered from the spleen of recipient mice are shown. The dashed lines represent the average Foxo1 MFI of the corresponding T-cell subset from the spleen of young adult (----) and old (….) recipient mice. d Distribution of CD4_N, CD4_M and CD4_R cells among donor CD4 T cells recovered from the indicated SLOs of young adult versus old recipient mice. e Absolute cell numbers of CD4_N, CD4_M and CD4_R donor cells recovered from the spleen of young adult versus old recipient mice per 10⁶ injected cells.Percentages of PD1⁺ (f) and KI67⁺ (g) cells among CD4_M and CD4_R donor cells are shown for the indicated SLOs of old versus young adult recipient mice. The dashed lines represent the average percentages for the corresponding T-cell subset of young adult (----) and old (….) recipient mice. h Percentages of PD1⁺ cells among CD4_M and CD4_R donor cells recovered from the spleen of recipient mice are shown as a function of their Foxo1 relative expression. i Percentages of KI67⁺ cells among CD4_M and CD4_R donor cells recovered from the spleen of recipient mice are shown as a function of their expression of PD1. Quantifications are represented as Means ± SEM. The significance of differences between two series of results was assessed using Student’s unpaired t test (c, e, f, g). For assessing correlations, Pearson correlation (two-sided test, coefficient, and 95% confidence intervals) was used (a, h, i). Significant (p < 0.05) or almost significant (0.05 < p < 0.10) p-values are indicated. Source data are provided as a Source Data file.