Young J W, Szabolcs P, Moore M A
Laboratory of Cellular Physiology and Immunology, Rockefeller University, New York 10021, USA.
J Exp Med. 1995 Oct 1;182(4):1111-9. doi: 10.1084/jem.182.4.1111.
Several cytokines, especially granulocyte/macrophage colony-stimulating factor (GM-CSF) and tumor necrosis factor alpha (TNF-alpha), have been identified that foster the development of dendritic cells from blood and bone marrow precursors in suspension cultures. These precursors are reported to be infrequent or to yield small numbers of dendritic cells in colony-forming assays. Here we readily identify dendritic cell colony-forming units (CFU-DC) that give rise to pure dendritic cell colonies. Human CD34+ bone marrow progenitors were expanded in semi-solid cultures with serum-replete medium containing c-kit-ligand, GM-CSF, and TNF-alpha. The addition of TNF-alpha to GM-CSF did not alter the number of typical GM colonies but did generate pure dendritic cell colonies that accounted for approximately 40% of the total colony growth. When the two distinct types of colonies were plucked from methylcellulose and tested for T cell-stimulatory activity in the mixed leukocyte reaction, the potency of colony-derived dendritic cells exceeded that of CFU-GM progeny from the same cultures by at least 1.5-2 logs. Immunophenotyping and cytochemical staining of the CFU-DC-derived progeny was also characteristic of dendritic cells. Other myeloid cells were not identified in these colonies. The addition of c-kit-ligand to GM-CSF- and TNF-alpha-supplemented suspensions of CD34+ bone marrow cells expanded CFU-DCs almost 100-fold by 14 d. We conclude that normal human CD34+ bone marrow cells include substantial numbers of clonogenic progenitors, distinct from CFU-GMs, that can give rise to pure dendritic cell colonies. These CFU-DCs can be expanded for several weeks by in vitro culture with c-kit-ligand, and their differentiation requires exogenous TNF-alpha in addition to GM-CSF. We speculate that this dendritic cell-committed pathway may in the steady state contribute cells to the epidermis and afferent lymph, where dendritic cells are the principal myeloid cell type, and may increase the numbers of these specialized antigen-presenting cells during T cell-mediated immune responses.
已经鉴定出几种细胞因子，尤其是粒细胞/巨噬细胞集落刺激因子（GM-CSF）和肿瘤坏死因子α（TNF-α），它们在悬浮培养中促进血液和骨髓前体细胞发育为树突状细胞。据报道，这些前体细胞数量稀少，或者在集落形成试验中产生少量树突状细胞。在此，我们轻松鉴定出了能产生纯树突状细胞集落的树突状细胞集落形成单位（CFU-DC）。人CD34+骨髓祖细胞在含有c-kit配体、GM-CSF和TNF-α的富含血清的半固体培养基中进行扩增。向GM-CSF中添加TNF-α不会改变典型GM集落的数量，但会产生占总集落生长约40%的纯树突状细胞集落。当从甲基纤维素中挑选出这两种不同类型的集落，并在混合淋巴细胞反应中检测其对T细胞的刺激活性时，集落衍生的树突状细胞的效力比来自相同培养物的CFU-GM后代至少高1.5 - 2个对数。CFU-DC衍生后代的免疫表型分析和细胞化学染色也具有树突状细胞的特征。在这些集落中未鉴定出其他髓样细胞。向补充了GM-CSF和TNF-α的CD34+骨髓细胞悬液中添加c-kit配体，到第14天时CFU-DC扩增了近100倍。我们得出结论，正常的人CD34+骨髓细胞包含大量与CFU-GM不同的克隆形成祖细胞，它们能够产生纯树突状细胞集落。这些CFU-DC可以通过与c-kit配体进行体外培养扩增数周，并且它们的分化除了需要GM-CSF外还需要外源性TNF-α。我们推测，这种树突状细胞定向途径在稳态下可能为表皮和传入淋巴提供细胞，其中树突状细胞是主要的髓样细胞类型，并且在T细胞介导的免疫反应期间可能增加这些特殊抗原呈递细胞的数量。
