title: Selective loss of NK cytotoxicity in antisense NK-TR1 rat LGL cell lines. Abrogation of antibody-independent tumor and virus-infected target cell killing.
abstract: We have shown that NK-TR1, a protein containing a cyclophilin-like domain, is associated with a receptor/triggering molecule on the surface of human large granular lymphocytes (1). In the present study, we have further defined the role of NK-TR1 in target cell recognition/killing by generating antisense NK-TR1 transfectants in the rat LGL cell line, RNK-16. Stable transfectants were identified by analyzing permeabilized cells with the anti-NK-TR1 mAb, 4F9. Transfectants with low levels of 4F9 staining showed drastically reduced levels of killing against three NK-susceptible target cell lines. Lytic activity against vaccinia virus-infected cell lines also was dramatically reduced. In contrast, transfected cells showing normal levels of NK-TR1 expression demonstrated normal killing of all target cells. The ability of all transfectants to form conjugates was identical to that observed with the wild-type RNK cell line. Lectin-dependent cytotoxicity, reverse ADCC via NKR-PI, and ADCC-mediated killing were comparable in both high or low NK-TR1 expressing clones, demonstrating that the lytic machinery was still intact. BLT-esterase activity, PF levels, and surface marker phenotype were not significantly affected. These results provide strong evidence that NK-TR1 is an essential element in a signaling pathway leading to MHC unrestricted killing of tumor and virus-infected cells.
authors.affiliation: Biologic Carcinogenesis and Development Program, Program Resource, Inc./DynCorp, Frederick, MD 21702.
authors.forename: S L
authors.initials: SL
authors.lastname: Giardina
authors.forename: S K
authors.initials: SK
authors.lastname: Anderson
authors.forename: T J
authors.initials: TJ
authors.lastname: Sayers
authors.forename: W H
authors.initials: WH
authors.lastname: Chambers
authors.forename: G A
authors.initials: GA
authors.lastname: Palumbo
authors.forename: H A
authors.initials: HA
authors.lastname: Young
authors.forename: J R
authors.initials: JR
authors.lastname: Ortaldo
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000920:Antibody-Dependent Cell Cytotoxicity; D000954:Antigens, Surface / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D015415:Biomarkers; D001798:Blood Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D002460:Cell Line; D003601:Cytotoxicity Tests, Immunologic; D003602:Cytotoxicity, Immunologic / Q000502:physiology*; D016373:DNA, Antisense / Q000235:genetics*; D004274:DNA, Recombinant / Q000235:genetics; D007694:Killer Cells, Natural / Q000276:immunology*; D037102:Lectins; D051381:Rats; D055607:Receptors, Natural Killer Cell; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015398:Signal Transduction; D014162:Transfection; D014616:Vaccinia virus
chemical_list: D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D015415:Biomarkers; D001798:Blood Proteins; D016373:DNA, Antisense; D004274:DNA, Recombinant; D037102:Lectins; D055607:Receptors, Natural Killer Cell; D011993:Recombinant Fusion Proteins