Figure 1

Percent of cells expressing CTLA-4, ICOS, Tim-3 or PD-1 in young and older subjects. CD4+ T-cells day 0 (A) and day 3 of activation (B). CD8+ T-cells day 0 (C) and day 3 of activation (D). Day 3 cells were gated on CD25+ blasts and day 0 on resting lymphocytes. Percentage positive determined by Overton method compared to isotype control. Mean indicated with the black bar. Each age group has n = 24 in ICOS, Tim-3, PD-1 and n = 19 for CTLA-4. Significant differences between young and older groups at the p ≤ 0.05 level (two-tailed t-test) are noted.