Research Paper Volume 12, Issue 12 pp 12032—12050

Figure 5. Aged CD70⁺ T cells exhibit high susceptibility to apoptosis that can be reversed by blocking CD70. (A–D) Percentage of apoptotic cells (Annexin V⁺ 7AAD^-) (A–B) and expression of CD95 (C–D) in CD70^- and CD70⁺ T cells from elderly individuals (61-80 years, n = 17). Representative histograms (left) and plots (right) of the percentage of apoptotic cells are shown. The p-values were obtained by paired t-test (Annexin V) or Wilcoxon matched-pairs signed rank test (CD95). (E–F) Correlation analysis of percentage of HLA-DR⁺CD38^hi cells and percentage of Annexin V⁺ 7AAD^- cells (E) or CD95 expression (F) on CD4⁺ T cells (left) and CD8⁺ T cells (right) from all healthy donors. Spearman’s non-parametric test was used for correlation analysis. (G–J) Purified CD4⁺ and CD8⁺ T cells from elderly individuals (n = 8) were cultured in vitro with anti-human CD70 antibody or isotype IgG at a concentration of 10 μg/mL. After culturing for 24 h, the susceptibility to apoptosis was evaluated by flow cytometry. Representative histogram (left) and plot (right) of percentage of Annexin V⁺ 7AAD^- (G–H) and Annexin V⁺ CD95⁺ cells (I–J) in CD4⁺ and CD8⁺ T cells. The p-values were obtained by paired t-test (Annexin V⁺ 7AAD^- [CD8⁺ T cells], Annexin V⁺ CD95⁺ [CD8⁺ T cells]) or Wilcoxon matched-pairs signed rank test (Annexin V⁺ 7AAD^- [CD4⁺ T cells], Annexin V⁺ CD95⁺ [CD4⁺ T cells]). *p < 0.05, **p < 0.01, ***p < 0.001.