Control of hematopoiesis by dendritic cells

树突状细胞（DC）产生多种细胞因子，这些细胞因子可能调节造血干细胞（hsc）的分化，然而，树突状细胞与造血干细胞之间的关系细节尚不清楚。在这个项目中，我揭示了dc刺激剂TLR3在体外诱导hsc的迅速死亡。通过小鼠模型，我也证明了TLR9刺激或病毒感染诱导噬血细胞综合征，并且吞噬细胞是产生IL-10的单核细胞来源的树突状细胞。由此产生的IL-10可下调噬血功能，提示噬血功能是一种抑制过度免疫反应的新型免疫抑制机制。

Dendritic cells (DC) produce various cytokines which may regulate the differentiation of hematopoietic stem cells (HSCs), however, the details of the relationship between dendritic cells and HSCs remains unclear. In this project, I revealed that the DC-stimulator TLR3 induces the prompt death of HSCs in vitro. Using mouse model, I also demonstrated that TLR9 stimulation or viral infection induces hemophagocytic syndrome, and that the phagocytes are monocyte-derived dendritic cells that produce IL-10. The produced IL-10 down-regulated hemophagocytosis, which suggests that hemophagocytosis is a novel immune suppressive mechanism to suppress an excessive immune response.