The NKG2D receptor and its ligands - recognition beyond the missing self?

NKG2D is a surface receptor that activates natural killer (NK) cells and delivers a co-stimulatory signal to CD8-positive T cells. The ligands of NKG2D are induced by cellular stress and are specifically expressed by some tumor cells. This sparked the idea of an alternative regulation of NK cells by expression of induced self' ligands on target cells which can overcome the inhibition imparted by NMC class I-specific inhibitory receptors. (C) 2003 Editions scientifiques et medicales Elsevier SAS. All rights reserved.