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目的：寻找具有更强抗肿瘤活性及增强或抑制ＴＮＦα生物学活性的ＴＮＦα突变蛋白。方法和结果：应用ＰＣＲ技术对ｒｈＴＮＦα进行大片段缺失突变，构建了ｒｈＴＮＦα分子Ｎ端缺失５９个氨基酸的突变体ＴＮＦ６０的编码基因，插入ｐＢＶ２２０载体并在蛋白酶缺陷的大肠杆菌ＳＧ１１１７中获得较高表达，表达量为２０．４％。重组蛋白经变性、复性和纯化，纯度＞９７％。ＴＮＦ６０对Ｌ９２９，Ｈｅｐ－２，Ｕ９３７三株细胞均丧失了细胞毒性，但都表现出增强ｒｈＴＮＦα细胞毒性的作用。结论：ｒｈＴＮＦα大片段缺失突变体ＴＮＦ６０具有增强ｒｈＴＮＦα细胞毒性的作用
OBJECTIVE: To search for TNFα mutant proteins with enhanced antitumor activity and enhanced or inhibited TNFα biological activity. METHODS AND RESULTS: PCR was used to perform large fragment deletion mutation of rhTNFα. The gene coding for mutant TNF60 with 59 amino acid deletions in the N-terminus of rhTNFα was constructed and inserted into pBV220 vector and expressed highly in protease deficient E.coli SG1117. The expression level was 20.4%. The recombinant protein was denatured, renatured and purified with a purity of >97%. TNF60 lost cytotoxicity to L929, Hep-2, and U937 cells, but all of them showed the effect of enhancing cytotoxicity of rhTNFα cells. Conclusion: The large fragment deletion mutant TNF60 of rhTNFα can enhance the cytotoxicity of rhTNFα cells.