目的： 构建由人表皮生长因子和绿脓杆菌外毒素A组成的融合蛋白，并检测其对肿瘤细胞的杀伤能力。方法：利用基因工程技术连接EGF和PE35KDEL基因，克隆到表达载体pET28a中，将其转化至BL21（DE3），在BL21（DE3）以可溶的形式表达EGF-PE35KDEL嵌合毒素，经DEAE-Sepharose FF阴离子交换等层析后，纯度达到95%。结晶紫检测EGF-PE35KDEL对肿瘤细胞的活性。结果：SDS-PAGE和薄层扫描分析外源蛋白的表达量占菌体蛋白的20%。细胞活性检测证明EGF-PE35KDEL能够抑制Hela细胞的生长，IC50为0.07 μg/ml。结论：EGF-PE35KDEL嵌合毒素对体外表达EGFR的Hela细胞有杀伤作用。

Objective: To construct a chimeric toxin consisting of a EGF linked to PE35KDEL and evaluate the potential of the EGF-PE35KDEL to target and kill tumor cells. Methods: By using of genetic engineering techniques, a recombinant expressing plasmid pET28a-EGF-PE35KDEL was constructed, the new obtained plasmid pET28a-EGF-PE35KDEL was transformed into E.coli BL21(DE3) for proposed protein expression. EGF-PE35KDEL was purified by DEAE-Sepharose FF chromatography, cytotoxity EGF-PE35KDEL on Hela cell growth was analyzed with crystal violet staining. Results: The recombinant plasmid pet28a-EGF-PE35KDEL was constructed and expressed in E.coli. The recombinant EGF-PE35KDEL protein was expressed as a soluble protein and was up to 20% of the total protein in E. coli BL21(DE3). With the two purification procedure, the EGF-PE35KDEL is about 95% pure. The IC50 of EGF-PE35KDEL on Hela cell is 0.07 μg/ml. Conclusion: Chimeric toxin EGF-PE35KDEL had cytotoxicity to Hela cells which over expressed EGFR in vitro.