抗激活小鼠T细胞抗原单克隆抗体(2H3)识别的靶抗原分析

Analysis of the Target Antigen Recognized By The Monoclonal Antibody (2H3)

2H3为一株抗激活小鼠T细胞表面抗原的IgG_1型单克隆抗体。间接ELISA实验表明:它能与ConA 激活的小鼠脾细胞及IL—2依赖的CTLL—2细胞发生特异性结合。靶细胞免疫荧光染色法表明:上述两种靶细胞可与荧光标记的抗IL—2R单抗结合并可被事先与2H3作用所阻断,但该两种靶细胞与荧光标记抗Ia抗体的结合不能被2H3所阻断。对2H3所结合的靶细胞膜蛋白提取物进行的Western-Blotting实验表明:2H3识别的靶抗原分子量约为50～60KD。结果提示:2H3识别的靶抗原与小鼠细胞膜表面的IL—2R(P_(55)蛋白)是一致的,其免疫生物学活性正在进行分析中。

The McAb 2H3 to different target cells was investigated by using an indirect ELISA meth-ods. The result showed that the 2H3 could bind to the ConA actiuated mouse T lymphoblastsand CTLL-2 cells (an IL-2 dependent T cell line)but not to the resting mouse splenocytes,lymph node cells and thymocytes. The binding of FITC-anti-IL-2R to the activated mouse spleencells and CTLL-2 cells was seen as tested by immunofluorescence analysis. This binding reactionwas blocked when the target cells were previously treated with 2H3, but the binding reaction ofFITC-anti-Ia McAb to these target cells couldn't be blocded by 2H3. Further analysis of the tar-get antigen by using Western-Blotting technigue showed the molecular weight of this antihenrecognized by 2H3 was of 50～60KD in reducing condition. According to these data, target anti-gen recognized by the McAb 2H3 may be the IL-2R molecule(P_(55) mole cule)on the cell surface.