title: Decreased NK cell functions in obesity can be reactivated by fat mass reduction.
abstract: OBJECTIVE
  Natural killer (NK) cells are the first defense against malignant cells, and their functions are severely impaired in individuals with obesity. However, it is not known whether functions can be re-activated after weight loss. The alterations of NK cell functions after fat mass reduction were investigated.
  
  
  METHODS
  Thirty-two healthy adults with obesity were divided into control and experimental groups. Participants of the experimental group performed a 3-month program of exercise training and nutrition. Anthropometric, physiological, and metabolic parameters and plasma adipocytokines were determined. Peripheral blood mononuclear cells were analyzed by means of flow cytometry and Western blot assay for various NK cell-specific functional parameters and leptin signaling components. NK cell-mediated cytotoxicity assay with leptin stimulation was performed.
  
  
  RESULTS
  Male participants significantly decreased their body fat mass (P < 0.05) and increased physical fitness (P < 0.05). Plasma leptin levels were significantly reduced (P < 0.05) and intracellular interferon gamma (IFN-γ) expression in CD56(dim) NK cells was significantly increased (P < 0.001) 3 months after study end. Stimulation of NK-92 cells with different leptin dosages revealed a significant dose-dependent decrease of specific tumor cell lysis.
  
  
  CONCLUSIONS
  The present study demonstrates a reactivation of NK cell functionality after body fat mass reduction in persons with obesity.
authors.affiliation: Department of Anatomy and Cell Biology, Martin Luther University Halle-Wittenberg, Faculty of Medicine, Halle (Saale), Germany.
authors.forename: Janine
authors.initials: J
authors.lastname: Jahn
authors.affiliation: Institute of Performance Diagnostics and Health Promotion, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany.
authors.forename: Marco
authors.initials: M
authors.lastname: Spielau
authors.affiliation: Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany.
authors.forename: Corinna
authors.initials: C
authors.lastname: Brandsch
authors.affiliation: Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany.
authors.forename: Gabriele I
authors.initials: GI
authors.lastname: Stangl
authors.affiliation: Department of Orthopaedic Surgery and Traumatology, Martin Luther University Halle-Wittenberg, Faculty of Medicine, Halle (Saale), Germany.
authors.forename: Karl-Stefan
authors.initials: KS
authors.lastname: Delank
authors.affiliation: Department of Anatomy and Cell Biology, Martin Luther University Halle-Wittenberg, Faculty of Medicine, Halle (Saale), Germany.
authors.forename: Ina
authors.initials: I
authors.lastname: Bähr
authors.affiliation: Department of Anatomy and Cell Biology, Martin Luther University Halle-Wittenberg, Faculty of Medicine, Halle (Saale), Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Berreis
authors.affiliation: Dana-Farber Cancer Institute and Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Christiane D
authors.initials: CD
authors.lastname: Wrann
authors.affiliation: Department of Anatomy and Cell Biology, Martin Luther University Halle-Wittenberg, Faculty of Medicine, Halle (Saale), Germany.
authors.forename: Heike
authors.initials: H
authors.lastname: Kielstein
mesh_terms: D054392:Adipokines / Q000097:blood; D000328:Adult; D000886:Anthropometry; D015444:Exercise / Q000502:physiology; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007371:Interferon-gamma / Q000097:blood; D007694:Killer Cells, Natural / Q000276:immunology*; D020738:Leptin / Q000097:blood; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000276:immunology* / Q000628:therapy*; D015398:Signal Transduction; D015431:Weight Loss / Q000276:immunology*; D061217:Weight Reduction Programs
chemical_list: D054392:Adipokines; D020738:Leptin; D007371:Interferon-gamma