Bühring H J, Müller C A, Letarte M, Gougos A, Saalmüller A, van Agthoven A J, Busch F W
Section for Transplantation Immunology and Immunohematology, Medical University Clinic of Tübingen, Germany.
Leukemia. 1991 Oct;5(10):841-7.
A monoclonal antibody (1G2) was raised by immunization of a Balb/c mouse with the leukemic blasts from a patient suffering from chronic myelogenous leukemia blast crisis (CML-BC). Sequential immunoprecipitation of the protein from human umbilical vein endothelial cells with 1G2 and the endoglin-specific monoclonal antibody 44G4 indicated that both antibodies react with the same molecule, a homodimer of molecular mass 180,000. This protein was first identified on acute lymphoblastic leukemia and was shown to be primarily associated with endothelial cells. In addition, 1G2 and 44G4 identified the same subpopulation of human bone marrow mononuclear cells (BMMNC), as established by two colour immunofluorescence analysis. By cell sorting and colony assays it could be demonstrated that endoglin is not expressed on hemopoietic precursor cells (CFU-G, CFU-GM, CFU-GEMM, BFU-E). May-Grünwald-Giemsa staining of sorted BMMNC revealed that 1G2 recognized immature proerythroblasts and double-fluorescence analysis showed that endoglin is present on a subset of glycophorin A-positive BMMNC. 1G2 was not reactive on bone marrow B-cells (CD19, CD20), T-cells (CD3, CD7), natural killer cells (CD56), myeloid cells (CD13, CD14, CD15, CD33), and on CD34-positive cells. Endoglin contains an arginine-glycine-aspartic acid sequence, a feature generally associated with extracellular matrix proteins which interact with integrins. It is suggested that proerythroblasts may utilize endoglin to interact with integrins in cell-cell adhesion events in the stromal or hemopoietic compartment of the bone marrow.
用一名慢性髓性白血病急变期（CML - BC）患者的白血病原始细胞免疫Balb/c小鼠，制备出一种单克隆抗体（1G2）。用1G2和内皮糖蛋白特异性单克隆抗体44G4对人脐静脉内皮细胞中的蛋白质进行连续免疫沉淀，结果表明这两种抗体与同一分子发生反应，该分子是分子量为180,000的同二聚体。这种蛋白质最初在急性淋巴细胞白血病中被鉴定出来，并显示主要与内皮细胞相关。此外，通过双色免疫荧光分析确定，1G2和44G4识别相同的人骨髓单个核细胞（BMMNC）亚群。通过细胞分选和集落测定可以证明，造血前体细胞（CFU - G、CFU - GM、CFU - GEMM、BFU - E）上不表达内皮糖蛋白。对分选的BMMNC进行May - Grünwald - Giemsa染色显示，1G2识别未成熟的早幼红细胞，双荧光分析表明内皮糖蛋白存在于一部分血型糖蛋白A阳性的BMMNC上。1G2对骨髓B细胞（CD19、CD20）、T细胞（CD3、CD7）、自然杀伤细胞（CD56）、髓样细胞（CD13、CD14、CD15、CD33）以及CD34阳性细胞无反应。内皮糖蛋白含有精氨酸 - 甘氨酸 - 天冬氨酸序列，这一特征通常与与整合素相互作用的细胞外基质蛋白相关。提示早幼红细胞可能利用内皮糖蛋白在骨髓基质或造血区室的细胞 - 细胞黏附事件中与整合素相互作用。
