本实验从活化扁桃体细胞中克隆出人IL?21的cDNA并进行序列测定，同时构建了中国人IL?21表达克隆，并在DH5α宿主菌中表达出与谷胱甘肽转移酶融合的蛋白。采用琼脂糖珠结合的纯化方法，获得了与理论值相符合的纯化条带。在进一步的Western Blotting分析中显示，该种条件下表达的融合蛋白能与IL?2的单抗产生结合反应。这一实验结果结合人IL?21最新的结构分析和体外活性实验，进一步证实了人IL?21在临床与IL?2联用或单独使用具有的调节免疫功能和抗肿瘤活性[2,7]，并为进一步检测人IL?21的各种体内外活性奠定了理论和实验的基础。
【参考文献】
[1]PARRISH?NOVAK J, DILLON SR, NELSON A, et al. Interleukin 21 and its receptor are involved in NK cell expansion and regulation of lymphocyte function[J]. Nature, 2000,408(6808):57.
[2]ASANO R, KUDO T, MAKABE K, et al. Antitumor activity of interleukin?21 prepared by novel refolding procedure from inclusion bodies expressed in Escherichia coli[J]. FEBS Lett, 2002,528(1/3):70.
[3]BRENNE AT, BAADE RO T, WAAGE A, et al. Interleukin?21 is a growth and survival factor for human myeloma cells[J]. Blood, 2002,99(10):3756.
[4]KASAIAN M T, WHITTERS M J, CARTER L L, et al. IL?21 limits NK cell responses and promotes antigen?specific T cell activation: a mediator of the transition from innate to adaptive immunity[J]. Immunity, 2002,16(4):559?569.
[5]付强,钱冬萌,闫志勇,等. IL?21编码基因的克隆及其在大肠杆菌中的表达[J]. 青岛大学医学院学报, 2003,39(1):15?17.
[6]BONDENSGAARD K, BREINHOLT J, MADSEN D, et al. The existence of multiple conformers of interleukin?21 directs engineering of a superpotent analogue[J]. J Biol Chem, 2007,282(32):23326?23336.
[7]BAAN C C, BALK A H, DIJKE IE, et al. Interleukin?21: an interleukin?2 dependent player in rejection processes[J]. Transplantation, 2007,83(11):1485?1492.