Figure 4.

Increased tumor-infiltrating CD8⁺ T-cell apoptosis and blocking the PD-1/PD-L1 pathway cannot abrogate apoptosis. (a) Increased apoptosis of tumor- infiltrating CD8⁺ T cells upon incubation with anti-CD3 for 3 days. Cells were harvested and examined for apoptosis by double staining with annexin V⁺ and an antibody against CD8. Apoptosis was calculated as the percentage of annexin V⁺ cells in CD8⁺ fraction. (b) Apoptosis of tumor-infiltrating CD8⁺ T cells in the presence of anti-PD-L1 or anti-PD-L2. LC, lung cancer; PBMC, peripheral blood mononuclear cell; PD, programmed death.