Fig. 3
From: Immunotherapy of thymic epithelial tumors: molecular understandings and clinical perspectives
PD-1/PD-L1 signaling in tumor immune tolerance. A. The mechanism of PD-1/PD-L1-mediated inhibition of T cell activation and PD-1/PD-L1 blocker-mediated T cell function restoration (between APCs and T cells). B. The mechanism of PD-1/PD-L1-mediated tumor immune tolerance and PD-1/PD-L1 blocker-mediated antitumor activity. Blockade of PD-1/PD-L1 alone and in combination with anti-TGF-β restores immune-exhausted T cells. CTLA-4: Cytotoxic T lymphocyte-associated antigen 4; APC: Antigen-presenting cells; MHC: Major histocompatibility complex; TCR: T cell receptor; SHP2: Src homology 2 domain-containing tyrosine phosphatase 2