A transmembrane-anchored rat RAE-1-like transcript as a ligand for NKR-P2, the rat ortholog of human and mouse NKG2D.

NKG2D is a potent activating immunoreceptor that has been extensively characterized in NK cells and shown to lend costimulatory functions in CD8(+) T cells under certain conditions. The list is growing of ligands for NKG2D, which are distantly related to MHC class I molecule and are often up-regulated during cellular distress. Here, we describe the cloning of a novel (and incidentally the first) ligand for NKR-P2, the rat ortholog of human and mouse NKG2D, termed as rat RAE-1-like transcript (RRLT).

Involvement of NKR-P2/NKG2D in DC-mediated killing of tumor targets: indicative of a common, innate, target-recognition paradigm?

DC are the most efficient antigen-presenting cells that regulate the immune response. Here, we demonstrate the expression of NK cell receptor protein-2 (NKR-P2) on rat and mouse DC, and we show that NKR-P2 gets reorganized upon antigen contact. DC activated with anti-NKR-P2 mAb exhibit enhanced apoptotic killing of tumor targets, whereas blocking the interaction between NKR-P2 and its ligand with rNKR-P2 abrogated apoptotic killing, suggesting NKR-P2 to function as an activating molecule on DC.

Activating and inhibitory receptors and their role in natural killer cell function.

Last decade has seen a significant advancement in our understanding of the Natural Killer (NK) cell biology and function. Several receptors present on NK cells have been identified, which are involved in either their activation or inhibition. Similarly, a large number of interacting ligands have been identified on the target cells that upon interaction transmit either activating or inhibitory signals.