以含单链抗体 ( Sc Fv) 3H1 1基因全长的质粒 DNA为模板 ,利用 PCR技术扩增 3H1 1 Sc Fv基因片段 ,扩增片段及绿脓杆菌外毒素 PE38表达质粒 p YR39- 1 - PE38经 H ind /N de 酶切、连接 ,转化大肠杆菌 BL2 1,构建免疫毒素的表达质粒 p YR3H1 1 - PE38.转化菌在 IPTG诱导下 ,表达免疫毒素 3H1 1 - PE38,3H1 1 - PE38经纯化、变性、复性处理后 ,通过 MTT法检测其对胃癌细胞MGC80 3的杀伤活性 .结果表明 ,3H1 1 - PE38浓度不变 ,其杀伤率在一定的范围内随作用时间的延长而增加 ,当浓度为 5× 1 0 -8mol/L,作用时间为 60 h时 ,其对胃癌 MGC80 3细胞的杀伤率达74 .2 % ,而同等条件下抗 DNA免疫毒素 p Ig2 0 - PE38的杀伤率仅为 9.2 % ;作用时间一定 ( 60 h) ,免疫毒素浓度与杀伤率呈正相关 ,在 1 0 -10 mol/L以下 ,杀伤率几乎为零 ,而浓度高于 5× 1 0 -8mol/L时 ,杀伤率超过 70 % . 3H1 1 - PE38能够有效杀伤与之特异结合的胃癌细胞 ,具有潜在的应用前景 The full-length ScFv 3H1 1 gene containing plasmid DNA was used as a template to amplify the 3H1 1 Sc Fv gene fragment by PCR, and the amplified fragment and the PE38 expression plasmid pYR39-1 - PE38 of Pseudomonas exotoxin were extracted. After being digested and ligated with Hind/N de, the recombinant plasmid pYR3H1 1 - PE38 was transformed into Escherichia coli BL21 1. The transformed strain was expressed with the immunotoxin 3H1 1 - PE38, 3H1 1 - PE38 after being purified by IPTG. After treatment with denaturation and renaturation, the killing activity of gastric cancer cell MGC80 3 was measured by MTT assay. The results showed that the concentration of 3H1 1 - PE38 was unchanged, and its killing rate increased with the extension of the action time within a certain range. When the concentration was 5×10 -8 mol/L and the action time was 60 h, the killing rate of gastric cancer MGC80 3 cells reached 74. 2 %, while the killing rate of anti-DNA immunotoxin p Ig2 0 - PE38 under the same conditions was only At 9.2%; for a certain time (60 h), the immunotoxin concentration was positively correlated with the killing rate. Below 10 -10 mol/L, the killing rate was almost zero, while the concentration was higher than 5 × 10 -8 mol/L. The killing rate exceeds 70%. 3H1 1 - PE38 can effectively kill gastric cancer cells that specifically bind to it. , with potential application prospects