Imam A, Taylor C R, Tökés Z A
Cancer Res. 1984 May;44(5):2016-22.
Human milk fat globule membrane, which is said to derive from apical plasma membrane of secretory epithelial cells in breast, was analyzed by sodium dodecyl sulfate-two:dimensional gel electrophoresis. More than 35 components were detected in the gels. One of the major glycoproteins with an apparent molecular weight of 70,000, human milk fat globule membrane glycoprotein, was purified to homogeneity. The pattern of distribution of this glycoprotein in tissues was studied using polyclonal rabbit antibodies to the purified component. The localization of the antigen was accomplished by an indirect immunoperoxidase staining method. Normal mammary epithelial cells display this antigen mostly on the apical plasma membrane, whereas poorly differentiated breast carcinoma cells retained it predominantly in the cytoplasm. These observations suggest that the proper insertion of this glycoprotein into an apical membrane domain may be impaired in malignant tumor cells. In addition, a small population of tumor cells in each case examined failed to express detectable amounts of this component, indicating the presence of antigenic heterogeneity among the tumor cell population.
人乳脂肪球膜据说源自乳腺分泌上皮细胞的顶端质膜，通过十二烷基硫酸钠-二维凝胶电泳进行了分析。凝胶中检测到35种以上的成分。其中一种主要糖蛋白，表观分子量为70000的人乳脂肪球膜糖蛋白，被纯化至同质。使用针对纯化成分的兔多克隆抗体研究了这种糖蛋白在组织中的分布模式。通过间接免疫过氧化物酶染色法完成抗原定位。正常乳腺上皮细胞大多在顶端质膜上显示这种抗原，而低分化乳腺癌细胞则主要将其保留在细胞质中。这些观察结果表明，在恶性肿瘤细胞中，这种糖蛋白正确插入顶端膜结构域的过程可能受到损害。此外，在每个检测的病例中，一小部分肿瘤细胞未能表达可检测量的这种成分，表明肿瘤细胞群体中存在抗原异质性。
