丙型肝炎病毒F蛋白的原核表达及初步应用

Expression and preliminary study of HCV F protein gene

目的构建丙型肝炎病毒(HCV)F基因的原核表达载体,并在大肠杆菌TG1中进行表达,用以检测丙肝患者体内抗体,并制备抗血清。方法提取患者血清中的HCVRNA,并进行基因分型。取鉴定为HCV1b型的病毒,用RT-PCR扩增HCVF蛋白基因的序列。将扩增产物插入pGEM-T载体中,测序正确后,用EcoRI、BamHI双酶切后,再插入表达载体pGEX-4T-2中,转化大肠杆菌TG1,在IPTG诱导下表达GST-F蛋白。用亲和层析法纯化GST-F蛋白免疫BALB/c小鼠制备抗血清。并用纯化的GST-F蛋白进行ELISA法检测丙肝患者血清抗F蛋白抗体。结果在细菌裂解液中检测到重组的融合蛋白,经GlutathioneSepharose4B亲和层析柱纯化获得较高纯度的GST-F融合蛋白。应用Westernblot方法检测证实,用纯化的GST-F蛋白免疫BALB/c小鼠得到了特异性的抗体。用纯化的GST-F蛋白进行ELISA检测120例丙肝患者血清抗F蛋白抗体,82例呈阳性。结论通过上述方法制备的融合蛋白纯度较高,免疫小鼠获得的抗体具有良好的特异性。用纯化的目的蛋白检测丙肝患者血清抗F蛋白的抗体的阳性率为68%,与国外的报道接近,说明在HCV感染的自然病程中有F蛋白的产生,为研究HCVF蛋白及与HCV相关疾病的诊断和治疗提供了条件。

AIM： To express HCV F protein gene fragment in E. coli and detect if there is its antibody in HCV patients. METHODS： RNA of the virus identified as genetype 1b was choosed as template, the F protein gene was amplified by RT-PCR. This gene fragment was inserted into plasmid vector pGEM simple T. F gene was digested by EcoR I and BamH I from pGEM and cloned into plasmid vector pGEX-4T-2. The ligation mixture was transformed into E. coli. TGI and F fragment expression was induced by IPTG. The expressed protein was purified from lysates with Glutathione Sepharose 4B. The purified protein was used to identify whether there was anti-F antibody in the patients which HCV RNA was positive by ELISA. RESULTS： After IPTG induction, a positive band about 43 kD was detected. 82 of 120 HCV RNA positive＇s sera had anti-F antibody by ELISA. CONCLUSION： It is possible to efficiently express the HCV F protein in E, coil The positive rate of anti-F antibody in HCV RNA positive patients was 68%.