Figure 4

Age-associated changes in distribution of peripheral CD4 and CD8 T cells. Peripheral blood T cells from individual young (2–3 months of age, n = 10) and aged (18–22 months of age, n = 66 and >22 months of age, n = 36) mice were analyzed for distribution of CD4, CD8 and CD44. The median values of each population are shown with red bars. Panel A shows the CD4:CD8 ratio in young and aged mice. Data were analyzed by Mann–Whitney test (*p < 0.05, ***p < 0.0005). Panel B shows the age-related differences in the proportion of CD44^high cells among CD8 T cells. Panel C shows the age-related differences in the proportion of CD44^high cells among CD4 T cells. Data in panels B and C were analyzed by Mann–Whitney test (***p < 0.0005).