title: [K562 cells induces apoptosis of activated NK cells in vitro].
abstract: OBJECTIVE
  To investigate the apoptosis of NK cells induced by the erythroleukemia cell line K562 in vitro.
  
  
  METHODS
  Primary NK cells isolated from the peripheral blood of healthy donors by magnetic-activated cell sorting were cultured with stem cell medium containing recombinant human interleukin-2 (rhIL-2). The NK cells and K562 cells were mixed and co-cultured at different E:T ratios for different time lengths. The apoptosis of NK cells and K562 cells were detected using PE-AnnexinV/7-AAD labeling and flow cytometry.
  
  
  RESULTS
  The purity of isolated NK cells reached (93.99∓4.22)%. At the same E: T ratio, the apoptotic rate of NK cells induced by K562 cells increased significantly with time. As the E:T ratio reduced, the apoptotic rate of the NK cells increased and their cytotoxic activity against K562 cells was attenuated.
  
  
  CONCLUSIONS
  K562 cells can induce the apoptosis of activated NK cells, which is one of the probable mechanisms of immune escape of tumors.
authors.affiliation: Graduate Department, Hebei North University, Zhangjiakou 075000, China. cao.yan.happy@163.com
authors.forename: Yan
authors.initials: Y
authors.lastname: Cao
authors.forename: Lianning
authors.initials: L
authors.lastname: Duan
authors.forename: Chengrong
authors.initials: C
authors.lastname: Lu
authors.forename: Yuan
authors.initials: Y
authors.lastname: Luo
authors.forename: Peide
authors.initials: P
authors.lastname: Xiang
authors.forename: Shu
authors.initials: S
authors.lastname: Yan
authors.forename: Shujing
authors.initials: S
authors.lastname: Ge
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D017209:Apoptosis; D003602:Cytotoxicity, Immunologic; D006801:Humans; D020014:K562 Cells; D007694:Killer Cells, Natural / Q000166:cytology* / Q000276:immunology*; D019139:Tumor Escape