恶性疟原虫海南株var2csa基因的克隆、表达及免疫识别研究

目的克隆、表达恶性疟原虫海南株HN(2)var2csa基因DBL4、DBL5、DBL6区,通过ELISA方法比较其与硫酸软骨素A(CSA)的亲和能力差异,以及人体对恶性疟原虫海南株HN(1)、(2)VAR2CSA不同DBL区的免疫应答差异。方法根据DBL区序列设计3对引物,PCR扩增目的片段,并与pMD18-T克隆载体连接。经PCR、酶切、测序鉴定正确后克隆至表达载体pET-22b,通过转化、诱导、纯化表达重组蛋白质,SDS-PAGE和Western blot检测。通过ELISA方法进行重组蛋白质与CSA的粘附实验以及与患者血清的免疫识别实验。结果酶切及DNA测序结果均表明表达载体构建成功,表达并纯化3个DBL区重组蛋白质,分子量与预计大小相同,Western blott检测目的蛋白质具有免疫反应性,ELISA显示不同蛋白浓度条件下DBL5区均明显比其它两个DBL区有更高的OD405值,并且DBL5区被妊娠相关疟疾病人血清识别水平显著高。结论 var2csa基因3个DBL区重组蛋白质表达成功,DBL5区与CSA的粘附能力较强,人体对DBL5区的免疫应答反应可能在抗病免疫过程中起到关键作用。

Cloning,expression and characterization of HN isolate of Plasmodium falciparum var2csa genes and the encoded proteins

Objective To clone and express three VAR2CSA DBL domains(DBL4/5/6) encoded by the var2csa of a Hainan(2)isolate of Plasmodium falciparum,and analyze the difference of CSA-binding activity as well as immunological recognition among different domains.Methods The DBL domains were amplified by PCR and cloned into the vector pMD18-T,which were further verified by enzyme digestion and sequencing.The inserts with correct sequences were subcloned into the prokaryotic expression vector pET-22b,transformed into E.col...