Increased expression of exhaustion marker PD-1 on T-cells isolated from chronic spinal cord injury (SCI) mice. (A) Representative dot plots show the percentage of PD-1+ cells in gated CD4+ T-cells and CD8+ T-cells from uninjured (CT) and T9-SCI mice at chronic phase after injury (SCI). (B) Bar graphs show the mean ± SEM numbers of PD-1 expressing CD4+ T-cells and CD8+ T-cells. Twenty thousand events gated on live singlets were collected. n = 9 for CT mice, n = 11 for SCI mice. Data have been pooled across two independent experiments. *P < 0.05, one-tailed Student’s t-test.