Mechanism of reciprocal interaction between NK cells and radiation in target cells.

<p>NK cells damage target cell through perforin/granzyme B and death receptor/caspase mediated pathway. The radiosensitisation effect through NK cell depends more on the perforin/granzyme B pathway. Without radiation, the suboptimal activation of NK cells cause up-regulation of XIAP. With radiation, the mitochondria releases Smac to neutralize XIAP and enhances NK cell-mediated cytotoxicity.