Regulation of hematopoiesis by co-developing dendritic cells from human CD34+ cells.

肿瘤坏死因子-a （TNF-α）抑制红细胞生成，促进非红细胞集落形成。本研究探讨了这些非红系细胞的性质，并探讨了它们与红系祖细胞的生理作用。高度纯化的人CD34^+细胞在多种细胞因子（包括干细胞因子（SCF）、白细胞介素-3 （IL-3）和促红细胞生成素（EPO））存在和不存在TNF-α的情况下发生红细胞分化。我们列举了半固体期和液体悬浮培养中集落形成单位-红系（CFU-E）和糖蛋白A （GPA；红系谱系的特异性标记）阳性细胞。采用荧光活化细胞分选仪、酶免疫组织化学和共聚焦显微镜分析TNF-α作用下共发育非红系细胞的特性和作用。TNF-α抑制GPA^+细胞的生成，反之促进GPA^+细胞的生成。GPA细胞多为离心细胞，HLAⅰ类、HLAⅱ类、CD1a、CD4、CD11c、CD14、CD40、CD80、CD83和CD86阳性，但CD3、CD8、CD19、CD20和CD56阴性，表明树突状细胞（DC）在红细胞分化的同时也有共同发育。培养3天内检测到发育中的DC/DC前体。只有在TNF-α存在的情况下，CD34^+细胞通过形成聚集体增殖，其中GPA^+和CD11c+ DC/DC前体都存在。在培养期间，未成熟的CD11c^+ DC能够内吞受损的GPA^+细胞。综上所述，红细胞分化过程中由人CD34^+细胞共同生成的GPA细胞表达DC表型。CD11c^+ DC亚群与发育中的未成熟红细胞和受损的自身gpa ^+细胞发生物理和选择性结合，然后获得并捕获自身物质。TNF-α是炎症和/或组织损伤急性期反应的最早介质之一。因此，我们的研究结果表明，任何急性期反应都可以促进骨髓中CD34^+细胞的快速DC发展。少

Tumor necrosis factor-a (TNF-α) inhibits erythropoiesis and enhances non-erythroid colony formation. The present study examines the nature of these non-erythroid cells and investigates their physiological role in relation to erythroid progenitor cells. Highly purified human CD34^+ cells underwent erythroid differentiation in the presence of multiple cytokines, including stem cell factor (SCF), interleukin-3 (IL-3) and erythropoietin (EPO) with and without TNF-α. We enumerated colony-forming unit-erythroid (CFU-E) and glycophorin A (GPA ; a specific marker for erythroid lineage) positive cells in semisolid phase as well as in liquid suspension culture. The character and roles of co-developing non-erythroid cells in the presence of TNF-α were also analyzed using fluorescent activating cell sorter, enzyme immunohistochemistry and confocal microscopy. TNF-α inhibited the generation of GPA^+ cells and conversely enhanced the generation of GPA cells. The GPA cells were comprised of cells wit … More h excentric cell shape and were positive for HLA class I, HLA class II, CD1a, CD4, CD11c, CD14, CD40, CD80, CD83 and CD86, but not CD3, CD8, CD19, CD20 and CD56, indicating the co-development of dendritic cells (DC) along with erythroid differentiation. Developing DC/DC precursors were detected within 3 days of culture. Only in the presence of TNF-α, CD34^+ cells proliferated by forming aggregates where both GPA^+ and CD11c+ DC/DC precursors were present. During culture period, immature CD11c^+ DC were capable of endocytosing damaged GPA^+ cells. In conclusion, GPA cells co-generated from human CD34^+ cells during erythroid differentiation express DC phenotypes. CD11c^+ DC subset physically and selectively associates with developing immature erythorid cells and damaged self-GPA^+ cells and then obtains and captures self-substances. TNF-α is one of the earliest mediators of the acute phase response of inflammation and/or tissue damage. Therefore, our findings suggest that any acute phase response can facilitate rapid DC development from CD34^+ cells in bone marrow. Less