title: KIR receptor-ligand incompatibility predicts killing of osteosarcoma cell lines by allogeneic NK cells.
abstract: BACKGROUND
  The effectiveness of killer immunoglobulin-like receptor (KIR) incompatible, alloreactive natural killer (NK) cells has been primarily documented in hematological malignancies following stem-cell transplant. This effect has not been thoroughly evaluated for pediatric solid tumors. In this study, we evaluated KIR receptor-ligand incompatibility of NK cells against osteosarcoma cell lines.
  
  
  METHODS
  Following the KIR receptor-ligand mismatch model, MHC I cell surface expression and KIR ligand mRNA content of 3 osteosarcoma cell lines was determined by flow cytometry and quantitative reverse transcription-polymerase chain reaction (qRT-PCR), respectively. NK cells were isolated from healthy volunteer donor peripheral blood mononuclear cells (PBMCs) and KIR surface expression determined by flow cytometry. An Annexin-V based flow cytometric killing assay was used to determine % of dying osteosarcoma target cells by donor NK effector cells.
  
  
  RESULTS
  One of seven healthy volunteer donors tested lacked phenotypic expression of one KIR. However, variable expression of KIR ligands was observed in 3 osteosarcoma cell lines. The highest rates of dying cells were seen in osteosarcoma cells with the lowest KIR ligand expression. Following down-regulation of KIR ligand expression, an increased susceptibility to NK cell-mediated killing was observed in a previously NK-resistant osteosarcoma cell line.
  
  
  CONCLUSIONS
  Variable MHC I and KIR ligand expression was observed in osteosarcoma cell lines and this resulted in variable susceptibility to NK cell-mediated killing predicted by the degree of KIR receptor-ligand incompatibility. Collectively, these data provide rationale for the study of KIR incompatible stem-cell transplant for osteosarcoma, although further studies with fresh osteosarcoma samples are necessary.
authors.affiliation: Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA.
authors.forename: David
authors.initials: D
authors.lastname: Delgado
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Webster
authors.forename: Kenneth B
authors.initials: KB
authors.lastname: DeSantes
authors.forename: Emily T
authors.initials: ET
authors.lastname: Durkin
authors.forename: Aimen F
authors.initials: AF
authors.lastname: Shaaban
mesh_terms: D001859:Bone Neoplasms / Q000276:immunology* / Q000378:metabolism; D045744:Cell Line, Tumor; D003601:Cytotoxicity Tests, Immunologic; D003602:Cytotoxicity, Immunologic; D005434:Flow Cytometry; D006648:Histocompatibility; D015395:Histocompatibility Antigens Class I / Q000276:immunology / Q000378:metabolism; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology*; D008285:Major Histocompatibility Complex / Q000276:immunology; D012516:Osteosarcoma / Q000276:immunology* / Q000378:metabolism; D054340:Receptors, KIR / Q000276:immunology* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D015395:Histocompatibility Antigens Class I; D054340:Receptors, KIR