Figure 2.

4‐1BB–expressing PD‐1^high CD8⁺ TILs feature immunophenotypically and transcriptionally prominent T‐cell activation. (A) Representative flow cytometry plot showing subpopulations of PD‐1⁺ CD8⁺ TILs according to differential expression of PD‐1 and 4‐1BB. (B,C) Percentages of CD39⁺CD103⁺ cells (B) and CD38⁺HLA‐DR⁺ cells (C) among the PD‐1^int, 4‐1BB^negPD‐1^high, and 4‐1BB^posPD‐1^high subpopulations of total and NY‐ESO‐1₁₅₇–specific CD8⁺ TILs. Left panels show representative flow cytometry plots (B,C). (D,E) RNA‐seq data comparing expression of genes related to T‐cell activation among FACS‐sorted PD‐1^int, 4‐1BB^negPD‐1^high and 4‐1BB^posPD‐1^high CD8⁺ TILs. (D) Heatmap showing expression levels of T‐cell activation gene signatures among the PD‐1^int, 4‐1BB^negPD‐1^high, and 4‐1BB^posPD‐1^high subpopulations. (E) Relative enrichment of T‐cell activation gene signatures among PD‐1^int, 4‐1BB^negPD‐1^high, and 4‐1BB^posPD‐1^high CD8⁺ TILs. Dashed line marks the significance threshold (P = 0.05). *P < 0.05; ***P < 0.001.