title: In vitro increased natural killer cell activity of metastatic melanoma patients with interferon-α alone as opposed to its combination with 13-cis retinoic acid is associated with modulation of NKG2D and CD161 activating receptor expression.
abstract: OBJECTIVE
  Considering tumor-induced suppression of natural killer (NK) cell activity the aim of this study was to investigate the in vitro effect of a standard immunotherapeutic cytokine, interferon (IFN)α, and a less investigated agent, 13-cis retinoic acid (RA) on the functional and receptor characteristics of CD16-defined NK cells and their functionally diverse dim and bright subsets in patients with metastatic melanoma (MM).
  
  
  METHODS
  Peripheral blood lymphocytes (PBL) of patients with clinical stage IV MM were stimulated in vitro for 18 h in RPMI 1640 culture medium (CM) alone, CM supplemented with IFN-α (250 U7sol;ml), RA (10-6M) and their combination. NK cell activity was determined using standard 4 h radioactive cytotoxicity assay, while the expression of activating (NKG2D, CD1617rpar; and inhibitory (CD158a, CD158b) NK cell receptors on CD3-CD16+ NK cells and their functional bright and dim subsets were analyzed by flow cytometry.
  
  
  RESULTS
  NK cell cytotoxic activity was increased after in vitro treatment with IFN-α alone and in combination with RA, while only IFN-α induced increase in NKG2D and CD161 activating NK cell receptor expression. Contrary to this, RA treatment increased the expression of inhibitory KIR CD158b. IFN-α-obtained increase in CD161 expression was due to its induction on both NK cell subsets, while for NKG2D only on CD16bright subset.
  
  
  CONCLUSIONS
  The favorable enhancement of NK cell activity of MM patients obtained with IFN-α is associated with upregulation of activating NKG2D and CD161 receptors, while the lack of RA-associated upregulation is probably due to the shown increased expression of inhibitory KIR receptor CD158b after in vitro treatment with this agent.
authors: Institute of Oncology and Radiology of Serbia, Department of Experimental Oncology, Laboratory for Immunology, Belgrade, Serbia. konjevicg@ncrc.ac.rs
authors: G
authors: G
authors: Konjevic
authors: K
authors: K
authors: Mirjacic-Martinovic
authors: A
authors: A
authors: Vuletic
authors: N
authors: N
authors: Babovic
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D058851:GPI-Linked Proteins / Q000032:analysis; D006801:Humans; D016898:Interferon-alpha / Q000008:administration & dosage / Q000627:therapeutic use*; D015474:Isotretinoin / Q000008:administration & dosage; D007694:Killer Cells, Natural / Q000276:immunology*; D008297:Male; D008545:Melanoma / Q000188:drug therapy* / Q000276:immunology / Q000473:pathology; D008875:Middle Aged; D055651:NK Cell Lectin-Like Receptor Subfamily B / Q000032:analysis*; D055655:NK Cell Lectin-Like Receptor Subfamily K / Q000032:analysis*; D009362:Neoplasm Metastasis; D017452:Receptors, IgG / Q000032:analysis
chemical_list: C428200:FCGR3B protein, human; D058851:GPI-Linked Proteins; D016898:Interferon-alpha; C527203:KLRB1 protein, human; C527085:KLRK1 protein, human; D055651:NK Cell Lectin-Like Receptor Subfamily B; D055655:NK Cell Lectin-Like Receptor Subfamily K; D017452:Receptors, IgG; D015474:Isotretinoin