The tissue damage to the tumor caused by the ROS leads to release of DAMPs that activate host immune cells such as macrophages, neutrophils and dendritic cells in an analgous manner to the PAMPs released by invading pathogens. The DCs can take up antigens released by apoptotic tumor cells and migrate to draining lymph nodes, where they activate naive T cells to become tumor-specific cytotoxic T cells that can return to destroy the tumor. hv represents light.
DAMP: Damage-associated molecular pattern; DC: Dendritic cell; hv: Light; PAMP: Pathogen-associated molecular pattern; PDT: Photodynamic therapy; ROS: Reactive oxygen species.