1Department of Molecular Medicine, Pasteur Institute of Iran, Tehran, Iran
2Stem Cell Department, Stem Cell Research Center, Tehran, Iran
3Department of Hematology, Tarbiat Modares University, Tehran, Iran
4Department of Microbiology, Hematology and Immunology, Faculty of Medicine, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
5School of Biomolecular and Biomedical Sciences, Eskitis Institute for Cell and Molecular Therapies, Griffith University Nathan, Queensland, Australia
Background: Unrestricted somatic stem cells (USSC) are cord blood stem cells that have been considered as candidates for the regulation of immune responses. Therefore, potential exists for their use in the suppression of immune response after transplantation surgery. Objective: The aim of this study was evaluation of the effect of USSC on mixed lymphocyte reaction (MLR) as a model for graft rejection. Methods: USSC and mesanchymal stem cells (MSC) were isolated and cultured from cord blood and bone morrow, respectively. The immunophenotypes of USSC and MSC were evaluated by flow cytometery and USSC and MSC were co-cultured with peripheral blood lympho-cytes (PBL) in an MLR to evaluate the immunomodulatory effect of these cells as a percentage of the control response. Results: Current study demonstrated that prolifera-tion of lymphocytes in the MLR was decreased after treatment with USSC, in a similar fashion to that seen with MSC. Conclusion: It can be concluded that USSC have simi-lar regulatory effects as MSC on the MLR, which can be used as an indicator for poten-tial organ rejection after transplantation. Therefore, the immunregulatory effect of these cells could be used in the clinic during organ transplantation and in the management of autoimmunity.