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本文报道B链半乳糖结合位点封闭的蓖麻毒素—胃癌单克隆抗体(McAb)结合物的制备及其细胞毒特征.首先将引入碘乙酰基团的毒素与引入巯基的抗体反应,得到的结合物通过琼脂糖亲和层析柱除去仍保留半乳糖结合能力的部分.ELISA结果表明,结合物稀释至2 nmol/L水平,仍保留抗体结合活性.结合物对靶细胞在体外有较强的选择性杀伤作用,在0.1 pmol/L水平,对人胃癌细胞KATOⅢ的杀伤率为46％,优于McAb—蓖麻毒素A链结合物.结果表明,免疫毒素中B链的存在有助于增强A链的细胞杀伤作用。
This article reports the preparation and cytotoxicity of ricin-gastric cancer monoclonal antibody (McAb) conjugates with B-galactose binding sites blocked. First, the iodine-acetylated toxin was reacted with a thiol-incorporated antibody. The conjugate was passed through an agarose affinity column to remove the portion that still retained galactose binding capacity. The ELISA results showed that the conjugate was diluted to 2 nmol/L and retained the antibody binding activity. The conjugate was stronger against target cells in vitro. The selective killing effect, at the level of 0.1 pmol/L, had a killing rate of 46% for human gastric cancer cell KATOIII, which was superior to the McAb-ricin A chain conjugate. The results showed that the presence of the B chain in the immunotoxin was helpful Enhances cell killing of the A chain.