title: CD56dimCD16neg cells are responsible for natural cytotoxicity against tumor targets.
abstract: The activation of natural killer (NK) cells leads to degranulation and secretion of cytotoxic granula. During this process, the lytic granule membrane protein CD107a becomes detectable at the cell surface. Based on this phenomenon, we have analyzed by a novel flow cytometry-based assay, the number and phenotype of NK cells responding to tumor targets. Using human leukemia and lymphoma cell lines, we observed a close correlation between CD107a surface expression and target cell lysis, indicating that NK cell cytotoxicity can be assessed by this method. The number of degranulating NK cells was closely related to the ratio of effector and target cells and showed a maximum at a ratio of 1:1. Moreover, we were able to show that the population of CD56(dim)/CD16(neg) NK cells is primarily responsible for the cytotoxic activity against tumor targets whereas neither CD56(dim)/CD16(pos) nor CD56(bright) NK cells degranulated in response to the cell lines. Our results indicate that the CD107a assay represents a promising new method for the quantification and characterization of cells exhibiting natural cytotoxicity.
authors.affiliation: Department of Hematology, Oncology, and Transfusion Medicine, Charité-Campus Benjamin Franklin, Berlin, Germany. olaf.penack@charite.de
authors.forename: O
authors.initials: O
authors.lastname: Penack
authors.forename: C
authors.initials: C
authors.lastname: Gentilini
authors.forename: L
authors.initials: L
authors.lastname: Fischer
authors.forename: A M
authors.initials: AM
authors.lastname: Asemissen
authors.forename: C
authors.initials: C
authors.lastname: Scheibenbogen
authors.forename: E
authors.initials: E
authors.lastname: Thiel
authors.forename: L
authors.initials: L
authors.lastname: Uharek
mesh_terms: D015703:Antigens, CD / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics; D019002:CD56 Antigen / Q000032:analysis / Q000378:metabolism*; D015550:Cell Degranulation / Q000276:immunology; D045744:Cell Line, Tumor; D003602:Cytotoxicity, Immunologic; D005434:Flow Cytometry; D006801:Humans; D007113:Immunity, Innate; D007694:Killer Cells, Natural / Q000276:immunology* / Q000378:metabolism; D007938:Leukemia / Q000276:immunology*; D052118:Lysosomal-Associated Membrane Protein 1; D051907:Lysosomal Membrane Proteins; D010641:Phenotype
chemical_list: D015703:Antigens, CD; D019002:CD56 Antigen; D052118:Lysosomal-Associated Membrane Protein 1; D051907:Lysosomal Membrane Proteins