title: Multiparameter flow cytometry characterization of MHC class I negative mouse bone marrow cells.
abstract: BACKGROUND
  MHC-I down-regulation was described in foetal liver progenitors, and two different subsets of adult bone marrow derived stem cells. These cells, namely, MHC-I-/Thy1+ bone marrow derived liver stem cells (BMDLSC) and the multipotent adult progenitors (MAPC) differentiated into functioning hepatocytes. The aim of this paper was to characterize the MHC-I negative bone marrow compartment as it pertains to BMDLSC and MAPC.
  
  
  METHODS
  We performed multiparameter flow-cytometry analyses of the MHC-I negative compartment using hematopoietic (CD45, Ter119), and stem cell markers (Thy1.2, c-Kit, IL-3R, CD34) in adult mice.
  
  
  RESULTS
  When analysing CD45 and Ter119 expression, the MHC-I negative bone marrow compartment divides into four sub-populations: 1. CD45-/Ter119+: 86.0+/-4.4%; 2. CD45+/Ter119+: 0.2+/-0.1%; 3. CD45+/Ter119-: 11.6+/-3.0%; 4. CD45-/Ter119-: 2.0+/-2.1%. Stem cells markers were only expressed on MHC-I negative/ CD45+/Ter119- cells. In vivo, MAPC (Ter119-/CD45- cells) are composed of MHC-I negative (24%) and MHC-I positive cells and do not express any of the stem cell markers tested.
  
  
  CONCLUSIONS
  In conclusion, mouse BMDLSC and MAPC are two distinct stem cell populations. Down-regulation of MHC-I was the only common characteristic found between BMDLSC and MAPC suggesting that selection of MHC-I negative cells might represent an efficient strategy to enrich for bone marrow stem cells with liver developmental potential.
authors.affiliation: Department of Visceral and Transplantation Surgery, Inselspital, and University of Bern, Bern, Switzerland.
authors.forename: Mattia
authors.initials: M
authors.lastname: Quarta
authors.forename: Deborah
authors.initials: D
authors.lastname: Stroka
authors.forename: Adrian
authors.initials: A
authors.lastname: Keogh
authors.forename: Daniel
authors.initials: D
authors.lastname: Sidler
authors.forename: Itzhak
authors.initials: I
authors.lastname: Avital
authors.forename: Beat
authors.initials: B
authors.lastname: Gloor
authors.forename: Maurizio
authors.initials: M
authors.lastname: Muraca
authors.forename: Daniel
authors.initials: D
authors.lastname: Candinas
authors.forename: Daniel
authors.initials: D
authors.lastname: Inderbitzin
mesh_terms: D000818:Animals; D001789:Blood Group Antigens / Q000032:analysis; D001854:Bone Marrow Cells / Q000276:immunology* / Q000378:metabolism; D005434:Flow Cytometry / Q000379:methods*; D015395:Histocompatibility Antigens Class I / Q000032:analysis*; D017493:Leukocyte Common Antigens / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D001613:beta 2-Microglobulin / Q000378:metabolism
chemical_list: D001789:Blood Group Antigens; D015395:Histocompatibility Antigens Class I; C489122:TER-119 antigen, mouse; D001613:beta 2-Microglobulin; D017493:Leukocyte Common Antigens