Abstract
Dedifferentiated fat cells (DFATs), which are originated by the dedifferentiation of adipocytes, display surface markers of mesenchymal stem cells and are able to differentiate into different cell types, thus, yielding a huge therapeutic potential in repairing damaged tissues and organs. The use of allogeneic stem cells from healthy donors constitutes the basis of a new strategy for cell therapy in the field of transplantation and the first requirement for allografts is determining their immunological properties. In this study, human DFATs and ADSCs were passaged as in vitro models to investigate their immunomodulatory effects. Phenotypic analysis of cell surface markers and three-line differentiation protocols were used to identify stem cells. The immunogenic phenotypes of DFATs and ADSCs were analyzed by flow cytometry and a mixed lymphocyte reaction was used to assess their immune function. The characteristics of stem cells were confirmed by phenotypic identification of cell surface markers and three-line differentiation. Flow cytometry analysis showed that P3 generation DFATs and ADSCs contained human leukocyte antigen (HLA) class I molecules, but did not express HLA class II molecules and costimulatory molecules CD40, CD80 and CD86. Moreover, allogeneic DFATs and ADSCs could not induce the proliferation of peripheral blood mononuclear cells (PBMCs). In addition, both populations were shown to inhibit the Concanavalin A-stimulated proliferation of PBMCs and act as third-party cells responsible for inhibiting the mixed lymphocyte response. DFATs have immunosuppressive properties similar to ADSCs. Based on this, allogeneic DFATs have potential applications in tissue repair or cell therapy.