title: Human umbilical cord blood-derived stromal cells suppress xenogeneic immune cell response in vitro.
abstract: OBJECTIVE
  To explore immunological properties of human umbilical cord blood-derived stromal cells (hUCBDSC) and their effect on xenogeneic immune cells in vitro.
  
  
  METHODS
  Immunological phenotype of freshly isolated and cryopreserved hUCBDSCs was evaluated by flow cytometry. Xenogeneic splenic T-cells were stimulated by phytohemaglutinin A (PHA) or dendritic cells in the absence or presence of hUCBDSCs. T-cell proliferation was measured by cell counting kit-8 after 7-day incubation. The proportion of apoptotic cells and CD4+CD25+Foxp3+ regulatory T-cells (Tregs) was determined in T-cells activated by PHA in the absence or presence of hUCBDSCs by flow cytometry. Phenotype of dendritic cells, cultured alone or with hUCBDSCs, was analyzed by flow cytometry.
  
  
  RESULTS
  Levels of immune molecule expression on freshly isolated hUCBDSCs were as follows: human leukocyte antigen-I (HLA-I) (84.1+/-2.9%), HLA-II (1.6+/-0.3%), CD80 (0.8+/-0.1%), CD86 (0.8+/-0.1%), CD40 (0.6+/-0.1%), and CD40L (0.5+/-0.1%), which was not influenced by cryopreservation. T-cell proliferation in the presence of hUCBDSCs was significantly lower than that of positive control. The coculture led to a 10-fold increase (from 1.2+/-0.3% to 12.1+/-1.4%, P<0.001) in the proportion of CD4+CD25+Foxp3+ regulatory T-cells (Tregs) and a reversion of mature dendritic cells, as indicated by the down-regulation of major histocompatibility complex (MHC)-II molecule (49.3% vs 25.9%, P=0.001), CD80 (47.2% vs 23.3%, P=0.001), and CD86 (40.6% vs 25.1%, P=0.002). When subjected to annexin V binding and propidium iodide uptake assay, the hUCBDSCs did not show the ability to induce apoptosis of xenogeneic T-cells.
  
  
  CONCLUSIONS
  These results demonstrate low immunogenicity and immunomodulation effect of the hUCBDSCs. Reversion of mature dendritic cells and increase in Treg proportion, but not cell apoptosis, can possibly contribute to the suppression of xenogeneic T-cell proliferation by the hUCBDSCs.
authors: Department of Hematology, Xinqiao Hospital, Third Military Medical University, Chongqing, PR China.
authors: Lei
authors: L
authors: Hao
authors: Cheng
authors: C
authors: Zhang
authors: Xing-Hua
authors: XH
authors: Chen
authors: Zhong-Min
authors: ZM
authors: Zou
authors: Xi
authors: X
authors: Zhang
authors: Pei-Yan
authors: PY
authors: Kong
authors: Xue
authors: X
authors: Liang
authors: Lei
authors: L
authors: Gao
authors: Xian-Gui
authors: XG
authors: Peng
authors: Ai-Hua
authors: AH
authors: Sun
authors: Qing-Yu
authors: QY
authors: Wang
mesh_terms: D015703:Antigens, CD / Q000276:immunology*; D003713:Dendritic Cells; D005312:Fetal Blood; D006801:Humans; D055261:Immunogenetic Phenomena; D007165:Immunosuppression Therapy; D013154:Spleen / Q000166:cytology; D017154:Stromal Cells / Q000276:immunology*
chemical_list: D015703:Antigens, CD