Although monocytes represent an essential part of the host defence system, their accumulation and prolonged stimulation could be detrimental and may aggravate chronic inflammatory diseases. The present study has explored the less-understood immunomodulatory effects of mesenchymal stem cells on monocyte functions. Isolated purified human monocytes were co-cultured with human umbilical cord-derived mesenchymal stem cells under appropriate culture conditions to assess monocytes’ vital functions. Based on the surface marker analysis, mesenchymal stem cells halted monocyte differentiation into dendritic cells and macrophages and reduced their phagocytosis functions, which rendered an inability to stimulate T-cell proliferation. The present study confers that mesenchymal stem cells exerted potent immunosuppressive activity on monocyte functions such as differentiation, phagocytosis and Ag presentation; hence, they promise a potential therapeutic role in down-regulating the unwanted monocyte-mediated immune responses in the context of chronic inflammatory diseases.

尽管单核细胞是宿主防御系统的重要组成部分，但它们的蓄积和长时间的刺激可能有害，并可能加剧慢性炎症性疾病。本研究探索了间充质干细胞对单核细胞功能的免疫调节作用。在适当的培养条件下，将分离的纯化人单核细胞与人脐带来源的间充质干细胞共培养，以评估单核细胞的重要功能。根据表面标志物分析，间充质干细胞阻止单核细胞分化为树突状细胞和巨噬细胞，并降低其吞噬功能，从而无法刺激T细胞增殖。本研究认为，间充质干细胞对单核细胞的功能（如分化，吞噬作用和抗原呈递）具有有效的免疫抑制活性。因此，它们有望在慢性炎症性疾病中下调不需要的单核细胞介导的免疫反应中的潜在治疗作用。