Fig. 1

Peripheral T cell reservoirs decrease with age accompanied by an increase in the ratio of CD4 to CD8 cells. a The gating strategy for the T cell populations is shown. CD3 T cells were gated from the CD45 high population, CD4 and CD8 T subsets were gated from the CD3+ population. The total CD3 and CD8 but not CD4 T cell numbers decreased with age, but the difference between adjacent age groups is not significant; b Correlation and regression analysis of different T cell subsets and ages were calculated. The left represents the frequency, and the right represents the absolute number. The red points and bars represent the R-value and 95% confidence interval of the regression equation, and the P value to the right of the figure indicates the statistical significance of each subset. c The ratio of CD4 to CD8 increases with age, and three types of CD4/CD8 ratios (> 2; 1–2; < 1) have different frequencies in the young (3–59 years) and old (60–88 years) cohorts compared with an age-matched population of normal CD4/CD8 T cells. The group with the inverted CD4/CD8 ratio has a higher percentage of CD28- cells in the CD8 subsets