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白细胞介素 4受体 (IL 4R)特异地存在于多种肿瘤细胞表面 ,这为某些肿瘤的治疗提供了一个靶向标记。在以前的研究中 ,人白细胞介素 4 (hIL 4 )与白喉毒素 (DT)的融合蛋白 (DT4H)被构建 ,且它对某些肿瘤细胞系的高毒性得到了证明。但是 ,由于毒素部分的强免疫原性 ,它可以诱导人体的免疫反应。该研究中我们构建了白细胞介素 4与绿脓杆菌外毒素 (PE) 2 5 3～ 6 0 8aa的融合蛋白 ,并在其N端添加了 6×His标记方便纯化 ,在其C端添加了KDEL提高毒性。为了改善与IL 4R的亲和力我们将IL 4进行了环式重组 ,构建的融合毒素 ,H4 0 4K ,经DEAE$CSepharoseFastFlow及Ni NTA纯化后 ,纯度达 90 %。纯化后的H4 0 4K与DT4H相似 ,对U2 5 1高度敏感 ,对MCF 7及HepG2中度敏感 ,且我们首次证实该毒性不会被兔抗白喉毒素的多克隆抗体所抑制。这些研究表明 ,H4 0 4K与DT4H可以以一种互为替代的方式用于某些恶性肿瘤的治疗
Interleukin-4 Receptor (IL4R) is found specifically on the surface of a variety of tumor cells, providing a targeted marker for the treatment of certain tumors. In previous studies, a fusion protein of human interleukin 4 (hIL 4) and diphtheria toxin (DT) (DT4H) was constructed and its high toxicity to certain tumor cell lines was demonstrated. However, due to the strong immunogenicity of the toxin moiety, it can induce the body’s immune response. In this study, we constructed a fusion protein between interleukin-4 and PEI253 ~ 608aa, added 6 × His tag to the N-terminus to facilitate purification, and added C KDEL increases toxicity. In order to improve the affinity with IL 4R, IL 4 was circularly reorganized. The constructed fusion toxin, H440K, was purified to 90% purity by DEAE $ CSepharoseFastFlow and Ni NTA. The purified H4 0 4K is similar to DT4H, highly sensitive to U2 5 1, moderately sensitive to MCF 7 and HepG2, and we have for the first time demonstrated that this toxicity is not inhibited by polyclonal anti-diphtheria toxin antibodies in rabbits. These studies show that H4 0 4K and DT4H can be used in the treatment of certain malignancies in a reciprocal manner