Immune Modulatory Responses of Mesenchymal Stem Cells from Different Sources in Cultures and In Vivo

We present a comparison of immune-properties of mesenchymal stem cells (MSC) isolated from human placenta, umbilical cord matrix, adipose, and bone marrow. MSC collected from all these sources possess low levels of MHC-I and lacked MHC-II. These cells inhibited the mixed lymphocytic reaction in culture conditions when incubated with human allogeneic peripheral blood mononuclear cell (PBMNC) population. Even after differentiation into different cell lineages, these MSC are able to suppress the mixed lymphocytic reaction when cultured with stimulated allogeneic PBMNC. The cytokine profiles were determined for all types of MSC when co-cultured with PBMNC. IFNγ and IL-1β increased in supernatants of all co-cultures and whereas TNF-α, IL-1α, IL2 levels diminished. The low immunogenicity in vitro suggests that these cells can be used for allogeneic transplantation. A single infusion of MSC into immunocompetent BALB/c mouse resulted in immune suppressive changes in lymph nodes and spleen. Bone marrow and thymus remained largely unchanged. These findings suggest that MSC from AD, PL, and WJ could be substituted for BMSC. One can look for these sources particularly in cases where it is difficult to get the required number of autologous mesenchymal stem cells of bone marrow.