Morris L, Crocker P R, Gordon S
Sir William Dunn School of Pathology, University of Oxford, United Kingdom.
J Cell Biol. 1988 Mar;106(3):649-56. doi: 10.1083/jcb.106.3.649.
During mammalian development the fetal liver plays an important role in hematopoiesis. Studies with the macrophage (M phi)-specific mAb F4/80 have revealed an extensive network of M phi plasma membranes interspersed between developing erythroid cells in fetal liver. To investigate the interactions between erythroid cells and stromal M phi, we isolated hematopoietic cell clusters from embryonic day-14 murine fetal liver by collagenase digestion and adherence. Clusters of erythroid cells adhered to glass mainly via M phi, 94% of which bound 19 +/- 11 erythroblasts (Eb) per cell. Bound Eb proliferated vigorously on the surface of fetal liver M phi, with little evidence of ingestion. The M phi could be stripped of their associated Eb and the clusters then reconstituted by incubation with Eb in the presence of divalent cations. The interaction required less Ca++ than Mg++, 100 vs. 250 microM for half-maximal binding, and was mediated by a trypsin-sensitive hemagglutinin on the M phi surface. After trypsin treatment fetal liver M phi recovered the ability to bind Eb and this process could be selectively inhibited by cycloheximide. Inhibition tests showed that the Eb receptor differs from known M phi plasma membrane receptors and fetal liver M phi did not bind sheep erythrocytes, a ligand for a distinct M phi hemagglutinin. We propose that fetal liver M phi interact with developing erythroid cells by a novel nonphagocytic surface hemagglutinin which is specific for a ligand found on Eb and not on mature red cells.
在哺乳动物发育过程中，胎儿肝脏在造血过程中起着重要作用。对巨噬细胞（M phi）特异性单克隆抗体F4/80的研究表明，在胎儿肝脏发育中的红细胞之间散布着广泛的巨噬细胞质膜网络。为了研究红细胞与基质巨噬细胞之间的相互作用，我们通过胶原酶消化和贴壁从胚胎第14天的小鼠胎儿肝脏中分离出造血细胞簇。红细胞簇主要通过巨噬细胞粘附在玻璃上，其中94%的巨噬细胞每个细胞结合19±11个成红细胞（Eb）。结合的Eb在胎儿肝脏巨噬细胞表面强烈增殖，几乎没有摄取的迹象。巨噬细胞可以去除其相关的Eb，然后在二价阳离子存在下与Eb孵育重新构建细胞簇。这种相互作用所需的Ca++比Mg++少，半最大结合时分别为100μM和250μM，并且由巨噬细胞表面的一种胰蛋白酶敏感的血凝素介导。胰蛋白酶处理后，胎儿肝脏巨噬细胞恢复了结合Eb的能力，并且这个过程可以被环己酰亚胺选择性抑制。抑制试验表明，Eb受体不同于已知的巨噬细胞质膜受体，胎儿肝脏巨噬细胞不结合绵羊红细胞，绵羊红细胞是一种不同的巨噬细胞血凝素的配体。我们提出，胎儿肝脏巨噬细胞通过一种新型的非吞噬性表面血凝素与发育中的红细胞相互作用，这种血凝素对成红细胞上而非成熟红细胞上发现的一种配体具有特异性。
