Fig. 1: Age-related changes in A2/M1₅₈⁺CD8⁺ T cell frequencies and phenotypes.

a, ‘Lifespan’ HLA-A*02:01-positive cohort, median age and number of donors per age category. b, Age distribution within the HLA-A*02:01-expressing lifespan cohort. c, Representative FACS panels and gating strategy for A2/M1₅₈⁺CD8⁺ T cells in the enriched fraction and phenotypic populations T_CM (CD27⁺CD45RA⁻) cells, T_EM (CD27⁻CD45RA⁻), T_EMRA (CD27^-CD45RA⁺), T_naive (CD27⁺CD45RA⁺CD95⁻) and T_SCM (CD27⁺CD45RA⁺CD95⁺) cells. Gray dots represent total CD8⁺ T cells in the unenriched sample, red dots are A2/M1₅₈⁺CD8⁺ T cells in the enriched sample. d–g, Proportion of total CD8⁺ T cells (d,e) and frequency of A2/M1₅₈⁺CD8⁺ T cells (f,g) across different age groups. Open symbols indicate <10 A2/M1₅₈⁺CD8⁺ T cells counted, which were not used for phenotypic analyses. h,i, Frequency of naive and memory subsets within the total CD8⁺ T cell (h) or A2/M1₅₈⁺CD8⁺ T cell populations (i) across all age groups. j–m, Frequencies of CD57 and PD-1 expression on CD8⁺ T cells (j and l, respectively) and A2/M1₅₈⁺CD8⁺ T cells (k and m, respectively) per age group. Horizontal bars indicate the median, dots represent individual donors, with n = 11 newborns, n = 12 children, n = 20 adults and n = 18 older adults (b–h,j,l) and n = 10 newborns, n = 12 children, n = 20 adults and n = 16 older adults (i,k,m). Black line is a locally estimated scatter-plot smoothing) Loess trend line with error bands shaded in gray representing 95% confidence interval (CI) (e,g). Technical replicates were not performed due to limited samples. Statistical analysis was performed using a two-sided Kruskal–Wallis with Dunn’s correction for multiple tests. P values are indicated above the graphs. N, newborn; C, children; A, adult; OA, older adult.

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