抗天花粉蛋白单抗用于天花粉蛋白免疫毒素的亲和纯化

PURIFICATION OF TRICHOSANTHIN-MONOCLONAL ANTIBODY CONJUGATE BY MONOCLONAL ANTIBODY AFFINITY CHROMATOGRAPHY

天花粉蛋白（ＴＣＳ）是一种单链致核糖体失活的蛋白，用细胞融合技术筛选到一株分泌抗该蛋白单抗的杂交瘤细胞株（Ｔ１Ａ９），并将单抗Ｔ１Ａ９制成免疫亲和凝胶，用此亲和凝胶纯化以ＴＣＳ和抗人黑色素瘤单抗Ｎｇ７６构建的免疫毒素，能有效地分离掉样品中的游离抗体，提高免疫毒素的毒效。体外细胞毒性实验表明，亲和纯化的免疫毒素对黑色素瘤细胞（Ｍ２１）的杀伤作用比分子筛（ＳｅｐｈａｃｒｙｌＳ－２００）层析后的样品提高了６．３倍。它对Ｍ２１细胞的半致死浓度（ＩＣ＿（５０））为１．０×１０￣（－１０）ｍｏｌ／Ｌ。比ＴＣＳ和Ｎｇ７６的混合物的毒性（ＩＣ＿（５０）＝２．５×１０￣（－７）ｍｏｌ／Ｌ）提高了２５００倍。ＴＣＳ是制备免疫毒素的一种有效和常用的“弹头”，用此法纯化这类免疫毒素将会有一定的普遍性。

The hybridoma T1A9, which secreted monoclonal antibody directed against trichosanthin (TCS), a single chain ribosome inactivating protein, was screened by cell fusion technique, and an immunoaffinity gel composed with the monoclonal antibody T1A9 and Sepharose 4B was prepared. Using the affinity gel, have successfully purified an immunotoxin TCS-Ng76, which was constructed with TCS and anti-human melanoma monoclonal antibody Ng76, and the free Ng76 was completely removed from the immunotoxin preparation.The cytotoxicity of affinity purified TCS-Ng76 was enhanced 6.3-fold compared with that of purified TCS-Ng76 by Sephacryl S-200, and was 2 500-fold higher than that of mixture of TCS and Ng76. It is clear that the affinity gel maybe used in purification of different TCS composed immunotoxins.