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. Author manuscript; available in PMC: 2006 Nov 1.
Published in final edited form as: Int J Radiat Oncol Biol Phys. 2005 Nov 1;63(3):655–666. doi: 10.1016/j.ijrobp.2005.06.032

Figure 1. A model for the role of ionizing radiation in promoting cross-presentation of TAA and activation of anti-tumor T cells.

Figure 1

It is well-established that dendritic cells (DC) can efficiently uptake tumor associated antigens (TAA) from apoptotic and necrotic tumor cells and present them to both CD4+ and CD8+ cytolytic T cells (CTL), a process termed cross-presentation. By killing tumor cells ionizing radiation can promote this process. In the presence of adequate “danger signals” that induce DC maturation and up-regulation of co-stimulatory molecules CD80 and CD86, tumor-specific T cells are activated to produce pro-inflammatory cytokines and become effectors capable of killing the tumor cells. Recognition and killing of tumor cells by CTL may be further enhanced by the radiation-induced up-regulation of Fas and/or MHC I molecules on the tumor cells.