title: [HLA expression in human fetal bone marrow mesenchymal stem cells].
abstract: OBJECTIVE
  To investigate the expression of human leukocyte antigens (HLA) in human fetal bone marrow mesenchymal stem cells (MSCs) after long time culture as well as the changes in response to interferon-gamma (IFN-gamma) treatment.
  
  
  METHODS
  Human fetal MSCs were collected from 23 to 24-weeks-old fetues with the approval of Ethic Committee of Peking University Health Science Center. The cells of passage 5 and passage 12 were analyzed for HLA expression before and after IFN-gamma (50 microg/L) treatment by flow cytometry at different time points. The passage 5 cells were also treated with an additional dose of IFN-gamma (5 microg/L) and the HLA expression was analyzed 24, 48, 72, 96 and 120 h after treatment. RT-PCR was used to evaluate HLA-G and HLA-E expression at mRNA level in human fetal MSCs.
  
  
  RESULTS
  Flow cytometry results showed that fetal MSCs expressed high level of HLA class I (HLA-I) antigen, but extremely low level of HLA class II (HLA-II) antigen. The percentage of HLA-I positive MSCs in total MSCs was approximately over 50%, while that of HLA-II positive MSCs in total MSCs was less than 10%. IFN-gamma (50 microg/L) enhanced the HLA-I and HLA-II expression in a time dependent manner and increased the percentage of HLA-I positive cells in both passage 5 and passage 12 cells but preferably in passage 5 cells. The enhanced HLA-II expression was seen 48 h after IFN-gamma treatment in passage 5 cells (59.9%) but 72 h in passage 12 cells (48.1%). The treatment of 5 microg/L IFN-gamma also increased percentage of HLA-I and HLA-II positive MSCs, but with a relatively less extent compared to the 50microg/L IFN-gamma treatment group. RT-PCR result indicated HLA-G and HLA-E were expressed at mRNA level in human fetal MSCs.
  
  
  CONCLUSIONS
  Human fetal MSCs can be induced to express both HLA class I and class II antigens by IFN-gamma. The long time culture might reduce the IFN-gamma effects. Human fetal MSCs express HLA-G and HLA-E at mRNA level.
authors.affiliation: Division of Cardiology, Peking University Third Hospital, Beijing 100083, China.
authors.forename: Xiao-lu
authors.initials: XL
authors.lastname: Chen
authors.forename: Ping
authors.initials: P
authors.lastname: Chen
authors.forename: Zhu-qing
authors.initials: ZQ
authors.lastname: Jia
authors.forename: Yi-nan
authors.initials: YN
authors.lastname: Liu
authors.forename: Kang-tao
authors.initials: KT
authors.lastname: Ma
authors.forename: Yong-zhen
authors.initials: YZ
authors.lastname: Zhang
authors.forename: Chun-yan
authors.initials: CY
authors.lastname: Zhou
mesh_terms: D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D005333:Fetus; D005434:Flow Cytometry; D015870:Gene Expression / Q000187:drug effects; D006680:HLA Antigens / Q000096:biosynthesis / Q000235:genetics*; D015395:Histocompatibility Antigens Class I / Q000096:biosynthesis / Q000235:genetics; D000949:Histocompatibility Antigens Class II / Q000096:biosynthesis / Q000235:genetics; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000097625:HLA-E Antigens
chemical_list: D006680:HLA Antigens; D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II; D007371:Interferon-gamma; D012333:RNA, Messenger; D000097625:HLA-E Antigens