Alterman L A, Crispe I N, Kinnon C
Department of Immunology, University of London, GB.
Eur J Immunol. 1990 Jul;20(7):1597-602. doi: 10.1002/eji.1830200728.
The heat-stable antigen (HSA) is a marker of hematopoietic differentiation in both the B and T cell lineages. The antigen is recognized by a series of monoclonal antibodies which includes J11d, M1/69 and B2A2, and in addition YBM5.10.4. We show here that all these antibodies recognize the same antigenic determinant which is expressed on a variably glycosylated membrane protein. Tunicamycin experiments show that the antigen is not carbohydrate in nature as it is expressed on two unglycosylated protein core molecules of molecular mass ca. 20 kDa and 17 kDa. Furthermore, the antigenic determinant appears to be lost following phosphatidylinositol-specific phospholipase C cleavage. Although the molecular mass of HSA appears to be heterogenous on cells of different lineages, these variations in size appear to be due primarily to differences in the extent of N-linked glycosylation, since both protein core molecules were found in all cell types investigated which express the antigen. These findings have important implications for the structure and function of this antigen and its role in hematopoietic development.
热稳定抗原（HSA）是B细胞和T细胞谱系中造血分化的标志物。该抗原可被一系列单克隆抗体识别，包括J11d、M1/69和B2A2，此外还有YBM5.10.4。我们在此表明，所有这些抗体识别的是同一抗原决定簇，该决定簇表达于一种糖基化程度可变的膜蛋白上。衣霉素实验表明，该抗原本质上不是碳水化合物，因为它表达于分子量约为20 kDa和17 kDa的两种未糖基化的蛋白质核心分子上。此外，在磷脂酰肌醇特异性磷脂酶C切割后，抗原决定簇似乎会丢失。尽管HSA在不同谱系细胞上的分子量似乎具有异质性，但这些大小差异似乎主要是由于N-连接糖基化程度不同所致，因为在所有表达该抗原的研究细胞类型中均发现了这两种蛋白质核心分子。这些发现对该抗原的结构和功能及其在造血发育中的作用具有重要意义。
