Background: Although human embryonic stem cells (ESCs) and mesenchymal stem cells (MSCs) from various sources display immunomodulatory effects, direct comparisons among these classes of stem cells have not been reported.
Methods: Peripheral blood mononuclear cell suppression assays and carboxyfluorescein diacetate succinimidyl ester assays were used to assess the immunosuppressive effects of stem cells. Gene expression was measured using DNA microarrays.