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造血干细胞的增殖和分化受到全身性因素的控制;造血干细胞池的维持和控制亦受到直接的细胞间相互作用的影响。作者利用造血集落形成技术,对早期血发生中基质细胞与造血细胞间的相互作用进行电镜观察。作者发现:在成熟的骨髓巨噬细胞与形态未分化造血细胞之间存在一种交错相嵌连接(interdigitative coupling)。这种连接仅见于未分化细胞集落和粒细胞集落。红细胞集落中未见此类连接。假定造血干细胞(PSC)的形态特点是小的单个核和胞浆缺乏分化。PSC的微绒毛样突起突进成熟巨噬细胞袋状胞浆凹陷中,并和巨噬细胞表面皱褶相互缠绕在一起。PSC突起和巨噬细胞的胞膜之间存在一明显的、不规则的、电子透明的间隙,宽度大约为30nm,间隙内常含有与两平行胞膜相互垂直的纤细丝状物。邻近连接区的巨噬细胞的胞浆中可见小泡,这可能意味着某些物质的摄取或释放。从而证明了巨噬细胞与
Proliferation and differentiation of hematopoietic stem cells are controlled by systemic factors; the maintenance and control of hematopoietic stem cell pools are also affected by direct cell-cell interactions. The authors used hematopoietic colony formation technique to observe the interaction between stromal cells and hematopoietic cells during early blood generation by electron microscopy. The authors found that there is an interdigitative coupling between mature myeloid macrophages and morphologically undifferentiated hematopoietic cells. This connection is seen only in undifferentiated cell colonies and granulocyte colonies. No such attachment in erythrocyte colonies. It is hypothesized that the morphological features of hematopoietic stem cells (PSCs) are small single nuclei and lack of differentiation in the cytoplasm. The microvilli-like projections of PSC project into the pocket of cytoplasm of mature macrophages and entangle with the surface folds of macrophages. There is a clear, irregular, electron-transparent gap between the PSC protuberance and the macrophage cell membrane, with a width of about 30 nm, which usually contains fine filaments perpendicular to the two parallel membranes. Vesicles of macrophages adjacent to the junction can be seen in the cytoplasm, which may mean the uptake or release of certain substances. Thus proved that macrophages and