H5N1亚型禽流感病毒HA基因在昆虫细胞中的表达及其生物活性鉴定

The HA Gene of H5N1 Avian Influenza Virus Expressed in Insect Cells and Its Biological Activity

经RT-PCR扩增了H5N1亚型禽流感病毒血凝素基因(HA)片段,限制性内切酶酶切后将其克隆到pFastBacHTA杆状病毒转座载体,经酶切鉴定及测序,筛选出阳性重组转座载体pFastBac-H5。将pFastBacH5转化含有杆状病毒穿梭载体(bacmid)的DH10Bac感受态细胞,通过蓝白斑筛选和PCR鉴定获得重组杆状病毒穿梭载体rBacmid-H5。rBacmid-H5在脂质体介导下转染sf9昆虫细胞,SDS-PAGE蛋白电泳、Western blot、血凝试验和血凝抑制试验分析表明:分子量约63kDa重组血凝素蛋白(rH5)在sf9昆虫细胞中实现了高效表达。rH5具有血凝活性,而且其血凝活性能够被H5N1禽流感病毒高免血清所抑制;rH5免疫鸡诱导产生针对H5N1禽流感病毒亚型特异的血凝抑制抗体,说明表达的重组蛋白具有与天然蛋白相似的生物活性。

The 1.7 kb fuU-length hemagglutinin （HA） gene fragment of H5N1 subtype avian influenza virus was amplified by RT-PCR and then cloned into the pFastBacHT donor plasmids. The recombinant plasmid pFastBac-H5 was identified by restriction enzyme digestion and sequencing. Following the transposition pFastBac -H5 into the bacmid in DHIOBac E. coli competent cells, the colonies were identified by blue and white selection. The recombinant bacmid （rBacmid-H5） was verified by PCR analysis. Transfection of rBacmid-H5 DNA into sf9 cells using Cellfectin reagent results in the production of recombinant viral stock. Cells were harvested 72h post infection and analyzed by SDS-PAGE, Western-blot, hemagglutination and hemagglutination inhibition test;the expressed HA protein （rH5）shows hemaggluting activity and can be inhibited by H5 N1 virus immunized chicken sera. On the other hand, immunization of chickens with rH5 protein results in high titers of H5N1 virus specific hemagglutafion inhibition antibodies, which proved its biological activity.