Effective anti-tumor immunity begins with DCs. Tumor-infiltrating DCs capture dying tumor cells, process their proteins, and present peptides on MHC molecules. Cross-presentation allows DCs to present exogenous antigens on MHC-I, activating cytotoxic CD8+ T cells.
DC migration to tumor-draining lymph nodes brings antigen to T cell zones where priming occurs. The quality of this priming–influenced by checkpoint signaling–determines whether effective anti-tumor T cells are generated.