Mechanism of HLA-G participation in inhibiting lymphocyte proliferation by amniotic mesenchymal stem cells / 中国实验血液学杂志

This study was aimed to investigate the inhibitory mechanism of human amniotic mesenchymal stem cells (HAMSC) on lymphocyte proliferation and to validate the participation of the nonclassic human leukocyte antigen (HLA) class I molecule (HLA-G) in immunosuppressive action of HAMSC. HAMSC were isolated from fetal membranes of human placentas, and were cultured and expanded. The phenotypes of HAMSC were identified by flow cytometry, at same time the HLA-G levels on membrane surface and in cytoplasm were detected by flow cytometry. The soluble HLA-G (sHLA-G) level in HAMSC supernatants was determined by ELISA, MTT assay was used to examine the effect of mixed cultured HAMSC on proliferation of lymphocytes. The results showed that both surface and cytoplasm of HAMSC expressed HLA-G, the average rates of HLA-G expression on surface and in cytoplasm were (16.75 ± 3.871)% and (39.14 ± 4.274)%, respectively. The sHLA-G level in cell culture supernatant was 5.2 ng/ml. After HAMSC and culture supernatants were added in the MLR, the inhibitory rate on lymphocyte proliferation increased obviously, meanwhile the inhibitory rate on lymphocyte proliferation decreased when the HLA-G antibody was added in MLR. It is concluded that the surface and cytoplasm of HAMSC express HAL-G, at same time HAMSC secrete the HLA-G to supernatants of culture. The HLA-G is one of critical factors inhibiting immuno-function of HAMSC. This study contributes to improve the clinical therapeutic trails for using the HAMSC to prevent rejection.

Induction of dendritic cells with multidrug resistance from K562/MDR1 cells / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To induce the differentiation of K562/MDR1 cells into dendritic cells (DC) with multidrug resistance property.</p><p><b>METHODS</b>K562/MDR1 cells and K562 cells were cultured in the presence of GM-CSF and IL-4 to generate DC and matured by TNF-α. On d14 K562/MDR1-DC and K562-DC cells were harvested and the expressions of CD1a, CD83, CD80, CD86, HLA-ABC and HLA-DR were assessed by flow cytometry (FCM). The antigen presentation function of K562/MDR1-DC and K562-DC was determined by allogenic mixed lymphocyte reaction (Allo-MLR). The expression of P-glycoprotein and the intracellular accumulation of daunorubicin (DNR) were detected by FCM. The sensitivity of K562/MDR1-DC and K562-DC cell to vincristine, adriamycin was measured using MTT assay.</p><p><b>RESULTS</b>Both K562/MDR1 and K562 cells were differentiated into dendritic cells in the presence of cytokine cocktails, showing the morphologic and immunophenotypic characteristics of DC. K562/MDR1-DC more markedly enhanced proliferation of allogeneic lymphocytes in MLR than K562-DC. High level expression of P-glycoprotein and efflux of DNR were demonstrated in K562/MDR1-DC. K562/MDR1-DC showed multidrug resistance property, with higher IC(50) to VCR and ADM than that of K562-DCs.</p><p><b>CONCLUSION</b>K562/MDR1 cells can be differentiated into DC with the presence of cytokines, the induced K562/MDR1-DC cells express high level of P-glycoprotein and acquire the multidrug resistance property.</p>