Watanabe J, Okabe T, Fujisawa M, Takaku F, Fukayama M
Cancer Res. 1987 Feb 15;47(4):960-2.
Previous studies have demonstrated that monoclonal antibody TFS-4 recognizes a cell surface antigen with a molecular weight of 124,000 expressed selectively on small-cell lung cancer but not on non-small-cell lung cancers and that it cross-reacts with human brain. The antigenic determinant on small-cell lung cancer and that on brain shared common characteristics, i.e., trypsin sensitivity, heat lability, and neuraminidase resistance, suggesting that they are similar peptides (T. Okabe et al., Cancer Res., 44: 5273-5278, 1984; J-i. Watanabe et al., Cancer Res., 47:826-829, 1987). In order to elucidate the nature of this unique antigen recognized by TFS-4, we have purified the antigen to homogeneity from human brain. The antigen was solubilized from brain with 0.5% Nonidet P-40, precipitated with 50% ammonium sulfate, and subsequently purified by sequential chromatographies, i.e., diethylaminoethyl-Sepharose ion exchange, immunoaffinity, and gel permeation high-pressure liquid chromatography. The antigenic reactivity was assessed by immunoblotting using TFS-4 as a primary antibody. The purified antigen showed a single protein band with a molecular weight of 124,000 on sodium dodecylsulfate-polyacrylamide gel electrophoresis detected by a silver staining technique. The results suggest that the antigen on brain tissues is structurally related to the molecule expressed on small-cell lung cancer.
先前的研究表明，单克隆抗体TFS-4识别一种分子量为124,000的细胞表面抗原，该抗原在小细胞肺癌上选择性表达，而在非小细胞肺癌上不表达，并且它与人脑存在交叉反应。小细胞肺癌上的抗原决定簇与脑上的抗原决定簇具有共同特征，即对胰蛋白酶敏感、对热不稳定且对神经氨酸酶有抗性，这表明它们是相似的肽（T.冈部等人，《癌症研究》，44: 5273 - 5278, 1984；渡边治一等人，《癌症研究》，47: 826 - 829, 1987）。为了阐明TFS-4所识别的这种独特抗原的性质，我们已从人脑中将该抗原纯化至同质状态。该抗原用0.5%的诺乃洗涤剂P-40从脑中溶解出来，用50%的硫酸铵沉淀，随后通过一系列色谱法进行纯化，即二乙氨基乙基-琼脂糖离子交换色谱、免疫亲和色谱和凝胶渗透高压液相色谱。使用TFS-4作为一抗通过免疫印迹法评估抗原反应性。在十二烷基硫酸钠-聚丙烯酰胺凝胶电泳上，经银染技术检测，纯化后的抗原显示出一条分子量为124,000的单一蛋白条带。结果表明脑组织上的抗原在结构上与小细胞肺癌上表达的分子相关。
