title: Monocyte/macrophage-elicited natural killer cell dysfunction in hepatocellular carcinoma is mediated by CD48/2B4 interactions.
abstract: Defects in natural killer (NK) cell functions are necessary for tumor immune escape, but their underlying regulatory mechanisms in human cancers remain largely unknown. Here we show, in detailed studies of NK cells in 294 untreated patients with hepatocellular carcinoma (HCC), that accumulation of functional NK cells in HCC tissues could predict improved survival of patients. However, in patients with advanced-stage HCC, NK cells were significantly decreased in number with impaired tumor necrosis factor alpha (TNF-α) and interferon-gamma (IFN-γ) production. High infiltration of peritumoral stroma monocytes/macrophages was positively correlated with impaired functional activities of NK cells in intratumoral areas. Further kinetic experiments revealed that soon after exposure to tumor-derived monocytes, NK cells underwent a rapid, transient activation, but then they became exhausted, and eventually died. The monocytes from HCC tissues, but not from nontumoral liver, strongly express CD48 proteins; and such monocyte-induced NK cell dysfunction was markedly attenuated by blocking CD48 receptor 2B4 on NK cells, but not by blockade of NKG2D and NKp30.
  
  
  CONCLUSIONS
  These data reveal that human NK cells are regulated by a fine-tuned collaborative action between different types of immune cells, which may reflect a novel immune-escape mechanism by which tumors dynamically regulate their functions at distinct tumor microenvironments.
authors.affiliation: Key Laboratory of Gene Engineering of the Ministry of Education, School of Life Sciences, Sun Yat-sen University, Guangzhou, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wu
authors.forename: Dong-Ming
authors.initials: DM
authors.lastname: Kuang
authors.forename: Wei-Dong
authors.initials: WD
authors.lastname: Pan
authors.forename: Yun-Le
authors.initials: YL
authors.lastname: Wan
authors.forename: Xiang-Ming
authors.initials: XM
authors.lastname: Lao
authors.forename: Dian
authors.initials: D
authors.lastname: Wang
authors.forename: Xue-Feng
authors.initials: XF
authors.lastname: Li
authors.forename: Limin
authors.initials: L
authors.lastname: Zheng
mesh_terms: D015703:Antigens, CD / Q000276:immunology* / Q000378:metabolism; D017209:Apoptosis / Q000276:immunology; D000071178:CD48 Antigen; D006528:Carcinoma, Hepatocellular / Q000276:immunology* / Q000401:mortality / Q000473:pathology; D002450:Cell Communication / Q000276:immunology; D002470:Cell Survival / Q000276:immunology; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D007694:Killer Cells, Natural / Q000276:immunology* / Q000378:metabolism; D008113:Liver Neoplasms / Q000276:immunology* / Q000401:mortality / Q000473:pathology; D008264:Macrophages / Q000276:immunology / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000276:immunology* / Q000378:metabolism; D009364:Neoplasm Recurrence, Local / Q000276:immunology / Q000401:mortality / Q000473:pathology; D011971:Receptors, Immunologic / Q000276:immunology* / Q000378:metabolism; D000071176:Signaling Lymphocytic Activation Molecule Family; D059016:Tumor Microenvironment / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D015703:Antigens, CD; C084093:CD244 protein, human; D000071178:CD48 Antigen; C000604065:CD48 protein, human; D011971:Receptors, Immunologic; D000071176:Signaling Lymphocytic Activation Molecule Family; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma