title: NKR-P1A is a target-specific receptor that activates natural killer cell cytotoxicity.
abstract: NKR-P1A is a lectinlike surface molecule expressed on rat natural killer (NK) cells. NKR-P1A has structural and functional features of an activating NK cell receptor, but a requirement for NKR-P1A in target cell lysis has not been determined. To define the role of NKR-P1A in natural killing, we have generated a mutant of the rat NK cell line, RNK-16, lacking expression of all members of the NKR-P1 receptor family. Although these NKR-P1-deficient NK cells were able to kill many standard tumor targets, including YAC-1, they were selectively deficient in the lysis of IC-21 macrophage, B-16 melanoma, and C1498 lymphoma targets. Reexpression of a single member of the NKR-P1 family, NKR-P1A, on mutant cells restored lysis of IC-21, and killing of IC-21 targets through rat NKR-P1A was completely blocked by F(ab')2 anti-NKR-P1A. Reexpression of NKR-P1A also restored transmembrane signaling to IC-21, as assessed by the generation of inositol-1,4,5-trisphosphate. The generation of inositol-1,4,5-trisphosphate was also restored in response to B-16 targets, but both B-16 and C1498 cells remained resistant to lysis, indicating that other NK cell molecules, perhaps within the NKR-P1 family, are required for the efficient killing of these tumors. These results are the first to demonstrate that NKR-P1A is a target-specific receptor that activates natural killing.
authors.affiliation: Department of Medicine, University of California, San Francisco 94143, USA.
authors.forename: J C
authors.initials: JC
authors.lastname: Ryan
authors.forename: E C
authors.initials: EC
authors.lastname: Niemi
authors.forename: M C
authors.initials: MC
authors.lastname: Nakamura
authors.forename: W E
authors.initials: WE
authors.lastname: Seaman
mesh_terms: D000818:Animals; D000954:Antigens, Surface / Q000502:physiology*; D003602:Cytotoxicity, Immunologic; D007694:Killer Cells, Natural / Q000276:immunology*; D037181:Lectins, C-Type; D055651:NK Cell Lectin-Like Receptor Subfamily B; D051381:Rats; D011916:Rats, Inbred F344; D011971:Receptors, Immunologic / Q000502:physiology*; D014407:Tumor Cells, Cultured
chemical_list: D000954:Antigens, Surface; D037181:Lectins, C-Type; D055651:NK Cell Lectin-Like Receptor Subfamily B; D011971:Receptors, Immunologic