FIGURE 2.

TAMs inhibit the immunotherapy through interaction with T cells. (A) High CCL2 expression correlates with more tumor-infiltrated TAMs and fewer CD8⁺ T lymphocytes. (B) Expression of PD-1 on the TAMs inhibits macrophages on phagocytosis and anti-tumor immunity. (C) Expression of PD-L1/L2, Fas L and TRAIL in M2 macrophages promotes T cell anergy and apoptosis. TAMs, tumor-associated macrophages; CCL2, chemokine (C-C motif) ligand 2; CCR2, chemokine (C-C motif) receptor 2; IL-6, Interleukin-6; MIP-2, macrophage inflammatory protein 2; PD-1, programmed cell death protein 1; PD-L1/L2, programmed cell death 1 ligand 1/ligand 2; CTLA4, cytotoxic T-lymphocyte-associated protein 4; Fas L, Fas ligand; TRAIL, TNF related apoptosis inducing ligand.