Lymphocyte frequency, distribution, function and maintenance was assessed in 9 tissue sites acquired from 56 deceased organ donors, aged 3–73. (A) Age distribution of analyzed donors grouped into four life stages: Youth (0–5 years, white), Young Adult (16–35 years, light gray), Adult (36–65 years, gray), and Senior (66+ years, dark gray). (B) Race distribution of the organ donor population: White (green), Hispanic (blue), Black (yellow), and Asian (red). (C) Cause of death distribution of the organ donor population: Cerebrovascular stroke (gray), Head Trauma (orange), Anoxia (black), other causes (white). Characteristics of each individual donor including age, gender, height, weight, cause of death and serology are detailed in Table S1. (D) Flow chart of different parameters investigated and the analyses performed for this study from 56 donors, with blood and 8 tissues from each donor, analyzing 8 distinct CD4+ and CD8+ T cell subsets in terms of their function, proliferation, TCR diversity and homeostasis.