ABSTRACT
Myeloid-derived suppressor cells (MDSCs) are newly discovered cells derived from bone marrow that suppress immunity, playing an immunosuppressive role in tumors, infections, and autoimmune diseases. It has been confirmed in disease model studies that their immunosuppressive effect is mainly achieved by suppressing the function of T cells. At present, the treatment of infectious diseases is still a major obstacle, especially in the treatment of chronic infectious diseases. Studies have found that MDSCs have increased aggregation in infectious diseases. As MDSCs are gaining more attention in infectious diseases, their potential therapeutic effects may be further explored. This article mainly reviews the immunosuppressive mechanisms of MDSCs in infections such as bacteria, viruses, parasites and fungi and their relationship with the diseases.
ABSTRACT
PURPOSE: To explore the value of transplanting peripheral blood-derived mesenchymal stem cells from allogenic rabbits (rPBMSCs) to treat osteonecrosis of the femoral head (ONFH). MATERIALS AND METHODS: rPBMSCs were separated/cultured from peripheral blood after granulocyte colony-stimulating factor mobilization. Afterwards, mobilized rPBMSCs from a second passage labeled with PKH26 were transplanted into rabbit ONFH models, which were established by liquid nitrogen freezing, to observe the effect of rPBMSCs on ONFH repair. Then, the mRNA expressions of BMP-2 and PPAR-γ in the femoral head were assessed by RT-PCR. RESULTS: After mobilization, the cultured rPBMSCs expressed mesenchymal markers of CD90, CD44, CD29, and CD105, but failed to express CD45, CD14, and CD34. The colony forming efficiency of mobilized rPBMSCs ranged from 2.8 to 10.8 per million peripheral mononuclear cells. After local transplantation, survival of the engrafted cells reached at least 8 weeks. Therein, BMP-2 was up-regulated, while PPAR-γ mRNA was down-regulated. Additionally, bone density and bone trabeculae tended to increase gradually. CONCLUSION: We confirmed that local transplantation of rPBMSCs benefits ONFH treatment and that the beneficial effects are related to the up-regulation of BMP-2 expression and the down-regulation of PPAR-γ expression.