人4-1BBL胞外区基因的克隆与表达研究

用RT-PCR方法从人单核THP-1细胞系克隆人4-1BBL胞外区基因，将其重组到pAYZ表达载体中，构建成人4-1BBL胞外区基因表达载体。将该载体转化大肠杆菌16C9，获得稳定表达，表达产物主要以可溶性状态存在；SDS-PAGE和Western blot分析显示，其分子量约为22kD，与预期结果一致。这是首次在大肠杆菌中获得4-1BBL胞外区可溶性表达。生物学活性检测显示4-1BBL对于维持T淋巴细胞系因子释放非常有益，同时PI单染表明它能抑制Jurkat细胞的凋亡。这将在抗肿瘤免疫治疗中具有潜在应用前景。

Cloning and Expression of the Extracellular Domain of 4-1BBL

RT-PCR was used to clone DNA fragment of the extracellular domain of 4-1BBL from human THP-1 cells (human monocyte), and the expression vector pAYZ4-1BBL was constructed by cloning the extracellular domain of 4-1BBL into the expression vector pAYZ. The extracellular domain of 4-1BBL was expressed in E.coli 16C9 and purified by affinity chromatography. SDS-PAGE and Western blot analysis showed that the relativae molecular weight of soluble 4-1BBL is 22kD which was consistent with the theoretically predicted value. So far as we know, it is the first time that the soluble expression of 4-1BBL in E.coli.was achieved 4-1BBL induced a significant release of IL-2 in stimulated Jurkat cells after 48h incubation, especially in the presence of tumor cell. At the same time the apoptosis level of Jurkat cell reduce more than 50%. In conclusion,4-1BBL may be useful in cancer immunotherapy.