Matsuzaki H, Seon B K
Cancer Res. 1987 Aug 15;47(16):4283-6.
In the present work, we characterized the molecular nature of a T-cell acute lymphoblastic leukemia (T ALL) specific antigen, termed TALLA, which is defined by monoclonal antibody SN1. SN1 shows an extremely high specificity for T ALL. In the present study, SN1 was further shown not to react significantly with various normal solid tissues. TALLA was determined to be a glycoprotein with an approximate molecular weight of 150,000. However, the molecular nature of TALLA is peculiar in that heating at 100 degrees C for 2 min renders TALLA undetectable in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It should be noted that such heating is a common practice before analysis of proteins and glycoproteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. No significant antigenic modulation of TALLA was observed when T ALL cells were reacted with SN1. Two new monoclonal antibodies, SN1a and SN1b, which show the same cell binding specificity as SN1 were also generated in the present work and compared to SN1. Competitive binding experiments showed that the epitopes on TALLA recognized by SN1, SN1a, and SN1b are sufficiently close to one another to allow complete reciprocal inhibition of antibody binding. These epitopes apparently became more exposed to antibody when T ALL cells were treated with neuraminidase; neuraminidase-treated T ALL cells bind 29-35% more SN1, SN1a, and SN1b as compared to the original T ALL cells.
在本研究中，我们对一种T细胞急性淋巴细胞白血病（T-ALL）特异性抗原的分子性质进行了表征，该抗原被称为TALLA，由单克隆抗体SN1所定义。SN1对T-ALL显示出极高的特异性。在本研究中，进一步表明SN1与各种正常实体组织无明显反应。TALLA被确定为一种糖蛋白，其分子量约为150,000。然而，TALLA的分子性质很特殊，因为在100℃加热2分钟会使TALLA在十二烷基硫酸钠-聚丙烯酰胺凝胶电泳中无法检测到。应当注意的是，在通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳分析蛋白质和糖蛋白之前，这种加热是一种常见的操作。当T-ALL细胞与SN1反应时，未观察到TALLA有明显的抗原调制。在本研究中还产生了两种新的单克隆抗体SN1a和SN1b，它们与SN1具有相同的细胞结合特异性，并与SN1进行了比较。竞争性结合实验表明，SN1、SN1a和SN1b识别的TALLA上的表位彼此足够接近，能够完全相互抑制抗体结合。当用神经氨酸酶处理T-ALL细胞时，这些表位显然更容易与抗体结合；与原始T-ALL细胞相比，经神经氨酸酶处理的T-ALL细胞与SN1、SN1a和SN1b的结合增加了29%-35%。
