immunosuppressive activity of amniotic membrane mesenchymal stem cells on T lymphocytes

ABSTRACT

Mesenchymal Stem Cells [MSCs] are isolated from different sources like placenta. The placenta and its membranes like Amniotic Membrane [AM] are readily available and easy to work with. There is only limited knowledge on the immunomodulatory properties of human Amniotic Membrane-derived Mesenchymal Stem Cells [hAM-MSCs]. The aim of this study was to survey the suppressive activity of hAM-MSCs on T lymphocytes in vitro. Human AMs were obtained after caesarean section births from healthy women. After enzymatic digestion, cells were cultured and hAM-MSCs were obtained. In addition, human T lymphocytes were isolated and co-cultured with hAM-MSCs for 72 hr in the presence or absence of phytohemagglutinin [PHA]. Subsequently, proliferation of T cells was analyzed using BrdU and subsequently flow cytometry technique. Besides, the production of IL-4 and IFN-gamma was examined by ELISA method. Additionally, the expression of activation markers [CD38, HLA-DR] was studied on T lymphocytes by flow cytometry technique. It was revealed that hAM-MSCs could significantly suppress the proliferation of T lymphocytes [pproduction of IFN-gamma by T cells [p<0.05]. hAM-MSCs also down regulated the expression of activation markers on the surface of T lymphocytes, CD38 and HLA-DR. The difference was significant between the case and control samples [p<0.05]. All the comparisons were carried out between the case [Tcell+PHA+hAM-MSCs] and control [Tcell+PHA] groups. In conclusion, hAM-MSCs could inhibit the [mitogen-activated] T cells even in the absence of blood monocytes. Besides, hAM-MSCs-mediated inhibition of T lymphocytes was combined with down regulation of activation markers