Present and future of immune checkpoint blockade: Monotherapy to adjuvant approaches

Figure 1 Stimulatory and inhibitory responses mediated by immune checkpoints. Depicted are interactions between immune checkpoints and their ligands as well as their cellular effects. Stimulatory effects are depicted with green arrows, and inhibitory effects are depicted with red symbols. The effect of GITR ligation in NK cells is not yet fully understood. T REG: Regulatory T cell; DC: Dendritic cell; NK: Natural killer; MHC: Major histocompatibility complex; PD-1: Programmed death-1; KIR: Killer cell immunoglobulin like receptor; TCR: T-cell receptor; LAG-3: Lymphocyte activation gene-3; TIM-3: T-cell immunoglobulin and mucin protein-3; CTLA-4: Cytotoxic T lymphocyte associated antigen-4.