活性增强的SEC2截短突变蛋白的构建及其生物活性研究  

Construction and Study of Enhanced Superantigen Activity of Staphylococcal Enterotoxin C2 Truncated Mutant Protein

作　　者：张国俊[1,2] 邹谨[1,2] 徐明恺[1] 周隽逸[3] 张惠文[1] 

机构地区：[1]中国科学院沈阳应用生态研究所,辽宁沈阳110016 [2]中国科学院研究生院,北京100049 [3]沈阳药科大学,辽宁沈阳110016

出　　处：《生物技术》2012年第6期31-35,共5页Biotechnology

基　　金：国家科技重大专项重大新药创制项目(No.2012ZX09102301-013);沈阳市科技计划项目(No.F11-264-1-11;F12-152-9-00)资助~~

摘　　要：目的:分析金黄色葡萄球菌肠毒素C2的截短蛋白SEC14-239中7和9位氨基酸对其超抗原和抗肿瘤活性的影响。方法:利用基因工程方法将SEC14-239中7和9位Thr和Gly分别替换为Leu和Glu后,获得截短突变蛋白SEC14-239M。体外细胞学实验对其超抗原活性和抗肿瘤活性进行分析。结果:突变蛋白SEC14-239M体外刺激小鼠T细胞增值活性较SEC14-239显著增强(P<0.05),与未截短的SEC2相当(P>0.05)。在相同剂量条件下,SEC14-239M诱导的抗肿瘤活性尽管低于SEC2(P<0.01),但要显著高于SEC14-239(P<0.05)。结论:截短蛋白SEC14-239的第7和9位氨基酸突变后能显著增强其超抗原活性和抗肿瘤活性,但二者增强程度有差异。这一结果说明以定点突变改造SEC2截短体的活性是可行的,同时也暗示超抗原的T细胞增殖和诱导肿瘤细胞抑制并不完全关联。Objective：To analyze the effects of amino acid at position 7 and 9 of truncated protein SEC14 - 239 of Staphylococcus aureus enterotoxin C2 on its superantigen activity and antitumor activity. Method：The amino acids at position 7 and 9 （Thr and Gly） of SEC14 -239 were substituted for the Leu and Glu by genetic engineering methods and a truncated mutant protein SEClg - 239M was obtained. The superantigen activity and antitumor response of SEClg -239M were analyzed by cell biological methods in vitro. Result：The ability for truncated mutant protein SEC14 -239M to stimulate murine T - cell proliferation activity was significantly enhanced （P 〈 0.05 ） compared to SECI4 -239, and no significant difference compared to SEC2 （P 〉 0.05）. The antitumor activity of truncated mutant protein SEC14 - 239M was lower than SEC2 （P 〈0. 01 ） ,but significantly higher than SEC14 -239 （P 〈0. 05） at the same dosage. Conclusion：The su- perantigen activity and antitumor activity of SEC14 - 239M were strikingly enhanced by amino acids substitution at at position 7 and 9. However, the T cell proliferation activity was not completely in accordance with enhanced antitumor activity. Our result suggested that it was feasible to enhance the activities of SEC2 truncated mutant protein by using site - directed mutagenesis. Furthermore, this study also implied that the T cell proliferation activities and antitumor activities of superantigens are not completely associated.

关 键 词：金黄色葡萄球菌肠毒素C2 截短突变蛋白 超抗原活性 抑瘤活性 

分 类 号：Q816[生物学—生物工程] Q519