title: Bioactivity of umbilical cord blood dendritic cells and anti-leukemia effect.
abstract: OBJECTIVE
  We investigated the effect of umbilical cord blood dendritic cells (DCs) on in vitro proliferation, immunophenotypes and levels of homologous cytokine-induced killer cells (CIK) and the toxicity on leukemia cells.
  
  
  METHODS
  Mononuclear cell-induced DC-CIK cells derived from umbilical cord blood were collected and co-cultured in the proportion of 1:5. Cord blood CIK cells or peripheral blood DC-CIK cells were used as control. Phenotypes were analyzed by flow cytometry; vial cell counting was performed using trypan blue, and the killing activity of effector cells against leukemia cells was measured by MTT assay. The levels of interferon-r (IFN-r), tumor necrosis factor-a (TNF-α) and interleukin-12 (IL-12) were determined by ELISA.
  
  
  RESULTS
  The proliferative capacity of DC-CIK cells was obviously improved compared with cord blood CIK cells and peripheral blood DC-CIK cells (P<0.05, P<0.05). During the co-culture of cord blood DC-CIK cells, the ratios of CD 3 (+) CD 8 (+) and CD 3 (+) CD 56 (+) cells were obviously higher than that of CIK cells under the same conditions (P<0.05). On day 3 of co-culture, the levels of IL-12, IFN-r and TNF-a in cultured supernatant of cord blood DC-CIK cells were all higher than those secreted by CIK cells cultured alone (P<0.01, P<0.05, P<0.05). When the effector to target ratio was 2.5-20:1, the killing effect of cord blood DC-CIK cells against each subtype of acute leukemia cells was obviously higher than that of CIK cells (P<0.05). No significant differences in killing effect were observed for different subtypes. This finding was consistent with the killing effect of peripheral blood DC-CIK cells against leukemia cells.
  
  
  CONCLUSIONS
  Cord blood DCs can enhance the proliferative capacity of homologous CIK cells and its anti-leukemia effect. Though cord blood DC-CIK cells showed a higher proliferative capacity than peripheral blood DC-CIK cells, the two types of DC-CIK cells did not differ significantly in terms of cytoxicity. With a high availability and the low probability of graft rejection reaction, cord blood DC-CIK cells have a brighter prospect for application in immunotherapy.
authors.affiliation: Institute of Hematological Research, Shaanxi Provincial People's Hospital Xi'an 710068.
authors.forename: Xu-Cang
authors.initials: XC
authors.lastname: Wei
authors.affiliation: Institute of Hematological Research, Shaanxi Provincial People's Hospital Xi'an 710068.
authors.forename: Di-Di
authors.initials: DD
authors.lastname: Yang
authors.affiliation: Institute of Hematological Research, Shaanxi Provincial People's Hospital Xi'an 710068.
authors.forename: Xiu-Rui
authors.initials: XR
authors.lastname: Han
authors.affiliation: Institute of Hematological Research, Shaanxi Provincial People's Hospital Xi'an 710068.
authors.forename: Yu-An
authors.initials: YA
authors.lastname: Zhao
authors.affiliation: Institute of Hematological Research, Shaanxi Provincial People's Hospital Xi'an 710068.
authors.forename: Yan-Chun
authors.initials: YC
authors.lastname: Li
authors.affiliation: Institute of Hematological Research, Shaanxi Provincial People's Hospital Xi'an 710068.
authors.forename: Li-Jie
authors.initials: LJ
authors.lastname: Zhang
authors.affiliation: Institute of Hematological Research, Shaanxi Provincial People's Hospital Xi'an 710068.
authors.forename: Jiu-Ju
authors.initials: JJ
authors.lastname: Wang
keywords: Umbilical cord blood; co-culture; cytokine-induced killer cells (CIK); cytotoxicity; dendritic cells (DCs); leukemia