The human natural cytotoxicity receptors (NCR) that induce HLA class I-independent NK cell triggering.
The cytolytic activity mediated by human natural killer (NK) cells is the result of a balance between signals delivered by inhibitory and activating receptors. The inhibitory receptors are represented by different families of HLA-specific receptors characterized by immunoreceptor tyrosine-based inhibiting motif(ITIM) sequences in their cytoplasmic portion. The function and the specificity of the inhibitory receptors imply the existence of triggering receptors specific for non-HLA ligands that are responsible for the induction of the cytolytic activity against HLA class I-deficient target cells. These receptors have remained elusive until recently when three distinct NK-specific molecules, termed natural cytotoxicity receptors (NCR), were identified and cloned. The different members of this novel family of receptors play a complementary role in the recognition and lysis of target cells. The NCR family is composed by a heterogeneous group of molecules belonging to the Ig superfamily that associate to different immunoreceptor tyrosine-based activating motif (ITAM)-containing signal transducing polypeptides.
Bottino
C
C
Istituto Nazionale per la Ricerca sul Cancro, Genova, Italy. bottino@ermes.cba.unige.it
Biassoni
R
R
Millo
R
R
Moretta
L
L
Moretta
A
A
D003602:Cytotoxicity, Immunologic; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology*; D055627:Natural Cytotoxicity Triggering Receptor 1; D055629:Natural Cytotoxicity Triggering Receptor 2; D011971:Receptors, Immunologic / Q000276:immunology*
D015395:Histocompatibility Antigens Class I; C112260:NCR1 protein, human; C112837:NCR2 protein, human; D055627:Natural Cytotoxicity Triggering Receptor 1; D055629:Natural Cytotoxicity Triggering Receptor 2; D011971:Receptors, Immunologic