title: Identification of PVR (CD155) and Nectin-2 (CD112) as cell surface ligands for the human DNAM-1 (CD226) activating molecule.
abstract: Human natural killer (NK) cells express a series of activating receptors and coreceptors that are involved in recognition and killing of target cells. In this study, in an attempt to identify the cellular ligands for such triggering surface molecules, mice were immunized with NK-susceptible target cells. On the basis of a functional screening, four mAbs were selected that induced a partial down-regulation of the NK-mediated cytotoxicity against the immunizing target cells. As revealed by biochemical analysis, three of such mAbs recognized molecules of approximately 70 kD. The other mAb reacted with two distinct molecules of approximately 65 and 60 kD, respectively. Protein purification followed by tryptic digestion and mass spectra analysis, allowed the identification of the 70 kD and the 65/60 kD molecules as PVR (CD155) and Nectin-2 delta/alpha (CD112), respectively. PVR-Fc and Nectin-2-Fc soluble hybrid molecules brightly stained COS-7 cells transfected with the DNAM-1 (CD226) construct, thus providing direct evidence that both PVR and Nectin-2 represent specific ligands for the DNAM-1 triggering receptor. Finally, the surface expression of PVR or Nectin-2 in cell transfectants resulted in DNAM-1-dependent enhancement of NK-mediated lysis of these target cells. This lysis was inhibited or even virtually abrogated upon mAb-mediated masking of DNAM-1 (on NK cells) or PVR or Nectin-2 ligands (on cell transfectants).
authors.affiliation: Dipartimento di Medicina Sperimentale, Sezione di Istologia, Via G.B. Marsano 10, 16132 Genova, Italy. alemoret@unige.it
authors.forename: Cristina
authors.initials: C
authors.lastname: Bottino
authors.forename: Roberta
authors.initials: R
authors.lastname: Castriconi
authors.forename: Daniela
authors.initials: D
authors.lastname: Pende
authors.forename: Paola
authors.initials: P
authors.lastname: Rivera
authors.forename: Marina
authors.initials: M
authors.lastname: Nanni
authors.forename: Barbara
authors.initials: B
authors.lastname: Carnemolla
authors.forename: Claudia
authors.initials: C
authors.lastname: Cantoni
authors.forename: Jessica
authors.initials: J
authors.lastname: Grassi
authors.forename: Stefania
authors.initials: S
authors.lastname: Marcenaro
authors.forename: Nicolas
authors.initials: N
authors.lastname: Reymond
authors.forename: Massimo
authors.initials: M
authors.lastname: Vitale
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Moretta
authors.forename: Marc
authors.initials: M
authors.lastname: Lopez
authors.forename: Alessandro
authors.initials: A
authors.lastname: Moretta
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism*; D015703:Antigens, CD / Q000378:metabolism; D000945:Antigens, Differentiation, T-Lymphocyte; D015815:Cell Adhesion Molecules / Q000737:chemistry / Q000378:metabolism*; D002460:Cell Line; D003601:Cytotoxicity Tests, Immunologic; D006801:Humans; D007694:Killer Cells, Natural / Q000378:metabolism; D008024:Ligands; D008565:Membrane Proteins; D051379:Mice; D008807:Mice, Inbred BALB C; D000075983:Nectins; D010455:Peptides / Q000235:genetics / Q000378:metabolism; D011991:Receptors, Virus / Q000737:chemistry / Q000378:metabolism*; D000098862:T Lineage-Specific Activation Antigen 1
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D000098862:T Lineage-Specific Activation Antigen 1; D015815:Cell Adhesion Molecules; D008024:Ligands; D008565:Membrane Proteins; D000075983:Nectins; D010455:Peptides; D011991:Receptors, Virus; C066100:poliovirus receptor