Mesenchymal stem cells derived from human umbilical cord inhibit activation and proliferation of allogeneic umbilical cord blood T lymphocytes

Objective:To investigate the effects of human umbilical cord derived mesenchymal stem cells(hUC-MSCs)on the activation and proliferation of allogenic umbilical core blood T lymphocytes,so as to study the immunomodulatory capacity of hUC-MSC.Methods:hUC-MSCs were isolated,culture-expanded from human umbilical cord after enzyme digestion,and the major histocompatibility(MHC)phenotype features of hUC-MSC were detected.The experiment was divided into 3 groups:(1)Negative group:umbilical cord blood MNCs were cultured alone;(2)Control group:MNCs were cultured with nonspecific mitogenic stimuli;(3)Experimental group:MNCs were co-cultured with hUC-MSC and nonspecific mitogenic stimuli.FCM technique was used to detect the CD69 expression,an indicator of T-cell early activation,on T cells and CD4+,CD8+ subsets after 8 hours' co-culture.T-lymphocyte proliferation in each group was detected by MTT after 5 days' co-culture.Results:We successfully established a simple method to isolate and culture-expand abundant hUC-MSCs from human umbilical cord.The immunophenotypic analysis showed that hUC-MSCs expressed no HLA class Ⅱ and less HLA class Ⅰ.hUC-MSC inhibited CD69 expression in PHA and PMA activated T cells from(22.6±5.2)% to(7.8±3.5)%(P0.01)after 8 hours' co-culture,which influenced both CD4+ and CD8+ T-cell subsets.MTT showed that hUC-MSC dose-dependently inhibited PHA-induced T-lymphocyte proliferation.Conclusion:hUC-MSC has a dose-dependent inhibitory effect on nonspecific mitogenic stimuli-triggered activation and proliferation of allogeneic umbilical cord blood T lymphocytes,and the effect is not selective.