fig1

Figure 1. Mechanisms of immune-checkpoint inhibitors. ICIs target unique inhibitory checkpoint molecules expressed by T- and antigen-presenting cells. By blocking those receptors, ICIs promote the proper induction and differentiation of T cell-mediated immunity. In contrast, the absence of ICIs results in successful priming of checkpoint receptors with their ligands, thus inhibiting TCR activation overall, leading to cancer escape from immunosurveillance. APC: antigen-presenting cell; CD: cluster of differentiation; CTLA-4: cytotoxic T-lymphocyte associated antigen 4; mAb: monoclonal antibody; MHC: major histocompatibility complex; PD-1: programmed cell death protein 1; PD-L1: programmed cell death protein 1 ligand 1; TCR: T cell receptor.