title: Specific engagement of the CD94/NKG2-A killer inhibitory receptor by the HLA-E class Ib molecule induces SHP-1 phosphatase recruitment to tyrosine-phosphorylated NKG2-A: evidence for receptor function in heterologous transfectants.
abstract: It has been recently demonstrated that the CD94/NKG2-A killer inhibitory receptor (KIR) specifically recognizes the HLA-E class Ib molecule. Moreover, the apparent CD94-mediated specific recognition of different HLA class Ia allotypes, transfected into the HLA-defective cell line 721.221, indeed depends on their selective ability to concomitantly stabilize the surface expression of endogenous HLA-E molecules, which confer protection against CD94/NKG2-A+ effector cells. In the present study, we show that a selective engagement of the CD94/NKG2-A inhibitory receptor with a specific monoclonal antibody (mAb) (Z199) was sufficient to induce tyrosine phosphorylation of the NKG2-A subunit and SHP-1 recruitment. These early biochemical events, commonly related to negative signaling pathways, were also detected upon the specific interaction of NK cells with an HLA-E+ 721.221 transfectant (.221-AEH), and were prevented by pre-incubation of .221-AEH with an anti-HLA class I mAb. Furthermore, mAb cross-linking of the CD94/NKG2-A receptor, segregated from other NK-associated molecules by transfection into a rat basophilic leukemia cell line (RBL-2H3), promoted tyrosine phosphorylation of NKG2-A and co-precipitation of SHP-1, together with an inhibition of secretory events triggered via Fc epsilonRI. Remarkably, interaction of CD94/NKG2-A+ RBL cells with the HLA-E+ .221-AEH transfectant specifically induced a detectable association of SHP-1 with NKG2-A, constituting a more formal evidence for the receptor-HLA class I interaction.
authors.affiliation: Servicio de Inmunología, Hospital de la Princesa, Universidad Autónoma de Madrid, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Carretero
authors.forename: G
authors.initials: G
authors.lastname: Palmieri
authors.forename: M
authors.initials: M
authors.lastname: Llano
authors.forename: V
authors.initials: V
authors.lastname: Tullio
authors.forename: A
authors.initials: A
authors.lastname: Santoni
authors.forename: D E
authors.initials: DE
authors.lastname: Geraghty
authors.forename: M
authors.initials: M
authors.lastname: López-Botet
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000276:immunology*; D002460:Cell Line; D006680:HLA Antigens / Q000276:immunology*; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D007694:Killer Cells, Natural / Q000276:immunology*; D037181:Lectins, C-Type; D008024:Ligands; D008562:Membrane Glycoproteins / Q000276:immunology*; D051920:NK Cell Lectin-Like Receptor Subfamily D; D010766:Phosphorylation; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000276:immunology*; D051381:Rats; D015398:Signal Transduction / Q000276:immunology*; D014162:Transfection; D014443:Tyrosine; D000097625:HLA-E Antigens
chemical_list: D015703:Antigens, CD; D006680:HLA Antigens; D015395:Histocompatibility Antigens Class I; D047908:Intracellular Signaling Peptides and Proteins; D037181:Lectins, C-Type; D008024:Ligands; D008562:Membrane Glycoproteins; D051920:NK Cell Lectin-Like Receptor Subfamily D; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; D014443:Tyrosine; D000097625:HLA-E Antigens; C497869:KLRD1 protein, human; C497871:Klrd1 protein, rat; C516724:PTPN11 protein, human; C509249:PTPN6 protein, human; C516727:Ptpn11 protein, rat; C509250:Ptpn6 protein, rat