Immunotherapies: Exploiting the Immune System for Cancer Treatment

Figure 1

PD-1/PD-L1’s function in normal and tumor environments. (a) PD-1 on T cells binds to a PD-L1 ligand on APC, deactivating the T cell. (b) PD-1 is upregulated in exhausted T cells. (c) Tumor cells express PD-L1, as a survival tactic, which engages with PD-1 expressed by tumor antigen-specific T cells, and deactivate the T cell. (d) Checkpoint inhibitors targeting PD-1 and PD-L1 prevent the tumor cell from binding to PD-1 and thus allow T cells to remain active.

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