title: Preferential expansion of human umbilical cord blood-derived CD34-positive cells on major histocompatibility complex-matched amnion-derived mesenchymal stem cells.
abstract: BACKGROUND
  We previously found in a murine hematopoietic system that hematopoietic stem cells show high differentiation and proliferation capacity on bone marrow-derived mesenchymal stem cells/stromal cells (microenvironment) with "self" major histocompatibility complex (MHC).
  
  
  METHODS
  We examined whether amnion-derived adherent cells have the characteristics of mesenchymal stem cells, and whether these adherent cells can support the proliferation of umbilical cord blood-derived lineage-negative and CD34-positive cells (Lin(-)CD34(+) cells) obtained from the same fetus to a greater extent than those derived from other fetuses.
  
  
  RESULTS
  Culture-expanded amnion-derived adherent cells expressed mesenchymal stem cell markers and HLA-ABC molecules and could differentiate into osteoblasts, adipocytes and chondrocyte-like cells, indicating that the cells have the characteristics of mesenchymal stem cells. The Lin(-)CD34(+) cells purified from the frozen umbilical cord blood were strongly positive for HLA-ABC, and contained a large number of hematopoietic stem cells. When the Lin(-)CD34(+) cells were cultured on the autologous (MHC-matched) or MHC-mismatched amnion-derived adherent cells in short-term assays (hematopoietic stem cell-proliferation) and long-term culture-initiating cell assays, greater expansion of the Lin(-)CD34(+) cells was observed in the MHC-matched combination than in MHC-mismatched combinations. The concentration of granulocyte-macrophage colony-stimulating factor in the culture supernatants of the long-term culture-initiating cell assays was significantly higher in the MHC-matched combination than in MHC-mismatched combinations.
  
  
  CONCLUSIONS
  IT is likely that a MHC restriction exists between hematopoietic stem cells and mesenchymal stem cells/stromal cells in the human hematopoietic system and that granulocute-macropage colony-stimulating factor contributes to some extent to the preferential hematopoiesis-supporting ability of the MHC-matched amnion-derived adherent cells.
authors.affiliation: First Department of Pathology, Kansai Medical University, 10-15 Fumizono-cho, Moriguchi City, Osaka, Japan.
authors.forename: Tomomi
authors.initials: T
authors.lastname: Mizokami
authors.forename: Hiroko
authors.initials: H
authors.lastname: Hisha
authors.forename: Satoshi
authors.initials: S
authors.lastname: Okazaki
authors.forename: Takashi
authors.initials: T
authors.lastname: Takaki
authors.forename: Xiao-Li
authors.initials: XL
authors.lastname: Wang
authors.forename: Chang-Ye
authors.initials: CY
authors.lastname: Song
authors.forename: Qing
authors.initials: Q
authors.lastname: Li
authors.forename: Junko
authors.initials: J
authors.lastname: Kato
authors.forename: Naoki
authors.initials: N
authors.lastname: Hosaka
authors.forename: Muneo
authors.initials: M
authors.lastname: Inaba
authors.forename: Hideharu
authors.initials: H
authors.lastname: Kanzaki
authors.forename: Susumu
authors.initials: S
authors.lastname: Ikehara