Figure 2.

Ionizing radiation induces immunogenic cell death of tumors, which facilitates cross-priming of CTLs. Ionizing radiation induces translocation of calreticulin (CRT) to the tumor cell membrane, which acts as an “eat me” signal to dendritic cells (DCs), facilitating receptor mediated endocytosis through CD91. This makes tumor antigens available for cross-presentation on MHC-I for priming of tumor-specific T-cells. Radiotherapy also induces the release of danger associated molecular patterns (DAMPs), such as ATP and HMGB-1, which are endogenous immune adjuvants that stimulate DC activation, inducing DCs to provide co-stimulatory signals to naïve T-cells, facilitating cross-priming of CTLs. Together, these processes constitute immunogenic cell death of tumor cells.