title: [The effect of up-regulation of MHC class I chain-related antigen A expression by dendritic cells on activity of NK cells].
abstract: OBJECTIVE
  To observe whether MHC class I chain-related antigen A (MICA) was expressed on monocytes, immature dendritic cells (iDCs), and mature dendritic cells (mDCs), and to study effect of up-regulation of MICA expression by DCs on biologic activity of NK cells.
  
  
  METHODS
  MICA expression on monocytes, iDCs, or mDCs stimulated with LPS, TNF-α, CD40L, IL-15 or IFN-α was detected by flow cytometry. Next CD69 expression, degranuation, and IFN-γ production of NK cells stimulated with MICA-positive mDCs were analyzed. Lastly recombinant NKG2D/Fc fusion protein and anti-IL-12 monoclonal antibody was respectively added into culture systems to analyze whether these reagents affected the interaction between DCs and NK cells.
  
  
  RESULTS
  MICA was not expressed on monocytes, and expressed on iDCs at low level. LPS, TNF-α, CD40L had no influences on MICA expression on mDCs, but IFN-α, IL-15 up-regulated MICA expression on mDCs. MICA-positive mDCs promoted CD69 expression, IFN-γ production, and killing K562 cells by NK cells. NKG2D/Fc inhibited both cytotcoxicity and IFN-γ secretion, whereas IL-12 antibody only inhibited IFN-γ secretion of NK cells.
  
  
  CONCLUSIONS
  MICA expression on DCs is regulated by relevant factors in microenvironment. DCs with high level of MICA expression can up-regulate biologic activity of NK cells.
authors.affiliation: Department of Immunology, Medical College, the Second Affiliated Hospital, Yangzhou University, Yangzhou 225001, China. wjgong@yzu.edu.cn
authors.forename: Wei-juan
authors.initials: WJ
authors.lastname: Gong
authors.forename: Chun-xiang
authors.initials: CX
authors.lastname: Gong
authors.forename: Chang-rong
authors.initials: CR
authors.lastname: Wang
authors.forename: Wei-ming
authors.initials: WM
authors.lastname: Xiao
authors.forename: Li
authors.initials: L
authors.lastname: Qian
authors.forename: Ming-chun
authors.initials: MC
authors.lastname: Ji
mesh_terms: D045744:Cell Line, Tumor; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism*; D005434:Flow Cytometry / Q000379:methods; D015395:Histocompatibility Antigens Class I / Q000096:biosynthesis* / Q000276:immunology; D006801:Humans; D020014:K562 Cells; D007694:Killer Cells, Natural / Q000276:immunology* / Q000378:metabolism*; D009000:Monocytes / Q000276:immunology / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D015395:Histocompatibility Antigens Class I; C099187:MHC class I-related chain A