HLA expression in human fetal bone marrow mesenchymal stem cells / 北京大学学报(医学版)

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-?(IFN-?) 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-?(50 ?g/L) treatment by flow cytometry at different time points.The passage 5 cells were also treated with an additional dose of IFN-?(5 ?g/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-?(50 ?g/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-? treatment in passage 5 cells(59.9%) but 72 h in passage 12 cells(48.1%).The treatment of 5 ?g/L IFN-? also increased percentage of HLA-Ⅰ and HLA-Ⅱ positive MSCs,but with a relatively less extent compared to the 50?g/L IFN-? treatment group.RT-PCR result indicated HLA-G and HLA-E were expressed at mRNA level in human fetal MSCs.Conclusion: Human fetal MSCs can be induced to express both HLA class Ⅰ and class Ⅱ antigens by IFN-?.The long time culture might reduce the IFN-? effects.Human fetal MSCs express HLA-G and HLA-E at mRNA level.