ABSTRACT
Objective To explore the effect of umbilical cord mesenchymal stem cells with positive human leukocyte antigen(HLA)-G on inducing the production of regulatory T cells(Treg) in vitro.Methods Umbilical cord mesenchymal stem cells were isolated from umbilical cord of neonates. PEGFP-N1-HLA-G plasmid was transfected into the human umbilical cord mesenchymal stem cells by liposome transfection, as PEGFP-N1-HLA-G group. PEGFP-N1 empty vector plasmid was transfected into the human umbilical cord mesenchymal stem cells, as PEGFP-N1 group. The human umbilical cord mesenchymal stem cells without empty vector under the same conditions were set as blank control group. Markers of the umbilical cord mesenchymal stem cells were detected using flow cytometry. The expression of HLA-G protein in each group of cells was identified by Western Blot. After mixed-culturing with CD4+T cells in peripheral blood of healthy subjects for 24 h and 48 h, the proportion of CD4+CD25+Foxp3+Treg in total T cells of each group was detected by flow cytometry. Results CD45, CD34 and HLA-DR presented negative expression on umbilical cord mesenchymal stem cells, while CD29, CD44 and CD105 presented positive expression. HLA-G protein could be expressed in the PEGFP-N1-HLA-G group, which had statistically significant difference compared with the blank control group and PEGFP-N1 group (both P<0.01). After PEGFP-N1-HLA-G group and CD4+T cells were mixed-cultured for 24 h and 48 h, CD4+CD25+Foxp3+Treg accounted for (15.3±1.9)% and (14.3±2.1)% of the total T cells respectively, both of which presented statistically significant difference compared with the blank control group and PEGFP-N1 group (all P<0.05). Conclusions Umbilical cord mesenchymal stem cells with HLA-G gene modified can effectively induce the production of CD4+CD25+Foxp3+Treg in vitro.
ABSTRACT
OBJECTIVE: Habitual abortion(HA) is postulated to be due to several factors including immunogenetic mechanisms. Many studies have been conducted on the effect of the major histocompatibility(MHC) region in the reproductive phenomena suggesting an immunological or genetic involvement in HA. HLA-G is a nonclassical class I MHC molecule, with evidence of protecting cells against natural killer cell lysis and not stimulating an allogeneic response by peripheral blood T cells. These features suggest that expression of HLA-G could be a crucial factor for fetal survival in the face of a potentially hostile maternal immune system. The goal of this study was to investigate the immunogenetic role of HLA-G gene in the early pregnancy loss. This is the first report in Korea about the HLA-G gene in the patients of habitual abortion. METHODS: Twenty-one chorionic villi (study group) in the women with habitual abortion (at least 3 spontaneous abortion) and 10 normal chorionic villi (control group) in the women with therapeutic abortion were included in this study. The expression of HLA-G gene in placental extravillous cytotrophoblasts were made by reverse transcription-polymerase chain reaction(RT-PCR) and chromosomal analysis was done by ordinary GTG-banding method. Chi-square and Fisher's exact tests were used for the statistical analysis. RESULT: As a result, HLA-G mRNA was expressed in 52.4%(11/21) of study group, in 70%(7/10) of control group and there was no statistical significance. In study group, positive rate of HLA-G mRNA was 57.1%(4/7) in the patients with normal chromosome, and 50.0%(7/14) in the patients with abnormal chromosome and there was no statistical significance. CONCLUSION: Thus, these results suggest that HLA-G gene might not be a immunogentic marker of early pregnancy loss. But further large scale of study would be needed to reveal the role of HLA-G in habitual abortion.