Differential expression of endoglin on fetal and adult hematopoietic cells in human bone marrow.
Differential expression of endoglin on fetal and adult hematopoietic cells in human bone marrow.
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DOI：
10.4049/jimmunol.154.9.4456
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发表时间：
1995-05
影响因子：
4.4
通讯作者：
O. Rokhlin;M. Cohen;H. Kubagawa;M. Letarte;M. Cooper
中科院分区：
文献类型：
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作者：
O. Rokhlin;M. Cohen;H. Kubagawa;M. Letarte;M. Cooper
内皮糖蛋白是一种由人内皮细胞表达的糖蛋白，以高亲和力结合TGF-β 1和TGF-β 3。它最初是用针对人前B细胞系产生的44 G4 mAb鉴定的。我们现在报道，另一种抗前B细胞单克隆抗体29-G8与前B和前B白血病细胞反应，但不与成熟的B和T细胞反应，并识别内皮糖蛋白的不同表位。29-G8 mAb与重组内皮糖蛋白特异性结合，并从697 pre-B细胞系中免疫沉淀出具有M（r）95，000亚基的磷酸化同源二聚体糖蛋白。这种新的Ab去除了由原型44 G4抗内皮糖蛋白Ab鉴定的所有分子，但相反的情况并非如此。该前B细胞系上的29-G8+内皮糖蛋白分子亚群与44 G4 mAb不反应，因此表明这些抗内皮糖蛋白Ab看到不同的表位，其可以区分不同种类的内皮糖蛋白分子。使用29-G8 mAb的流式细胞术分析显示胎儿骨髓中存在两种内皮素阳性亚群：早期B系前体细胞（CD 19+和CD 34+）和原成红细胞（CD 71+和血型糖蛋白A+）。在成人骨髓中，仅观察到原成红细胞亚群。来源于胎儿骨髓的基质细胞也与29-G8和44 G4 Ab强烈反应，并且这些细胞在用TGF-β 1或抗内皮糖蛋白Ab刺激后以增强的增殖反应。因此，内皮糖蛋白，TGF-β受体系统的一个专门的组成部分，可能发挥生理作用的基质造血细胞的相互作用发生在发展过程中。
Endoglin, a glycoprotein that is expressed by human endothelial cells, binds TGF-beta 1 and -beta 3 with high affinity. It was originally identified with the 44G4 mAb that was produced against a human pre-B cell line. We now report that another anti-pre-B cell mAb, 29-G8, reacts with pro-B and pre-B leukemic cells, but not with mature B and T cells, and recognizes a different epitope of endoglin. The 29-G8 mAb bound specifically to recombinant endoglin and immunoprecipitated a phosphorylated homodimeric glycoprotein with subunits of M(r) 95,000 from the 697 pre-B cell line. This new Ab removed all of the molecules identified by the prototypic 44G4 anti-endoglin Ab, but the reverse was not true. A subpopulation of 29-G8+ endoglin molecules on this pre-B cell line was unreactive with the 44G4 mAb, thus suggesting that these anti-endoglin Abs see different epitopes that may discriminate different species of endoglin molecules. Flow cytometric analysis with the 29-G8 mAb revealed two endoglin-positive subpopulations in fetal bone marrow: early B-lineage precursor cells (CD19+ and CD34+), and proerythroblasts (CD71+ and glycophorin A+). In adult bone marrow, only the proerythroblast subpopulation was observed. Stromal cells derived from fetal bone marrow also reacted strongly with the 29-G8 and 44G4 Abs, and these cells responded with enhanced proliferation after stimulation with either TGF-beta 1 or the anti-endoglin Abs. Thus, endoglin, a specialized component of the TGF-beta receptor system, may play a physiologic role in the stromal-hemopoietic cell interactions occurring during development.