基因Ⅱ型草鱼呼肠孤病毒病毒样颗粒的构建与鉴定

Construction and identification of genotype Ⅱ grass carp reovirus virus-like particles

  • 摘要: 为研究Ⅱ型草鱼呼肠孤病毒 (GCRV)病毒样颗粒 (VLPs)疫苗,实验利用杆状病毒-昆虫细胞表达系统 (BEVS)将具有免疫原性的GCRV-VP3/VP4/VP35蛋白进行GCRV-VLPs的组装。实验将编码VP35蛋白的GCRV-s11基因克隆入杆状病毒载体pFastBacHTATM,然后将鉴定正确的重组质粒转化至DH10Bac感受态细胞,筛选得到重组穿梭质粒Bacmid-VP35。将穿梭质粒Bacmid-VP35以及实验室前期构建的重组穿梭质粒Bacmid-VP3、Bacmid-VP4分别转染Sf9昆虫细胞获得重组杆状病毒pFHB-VP35、pFHB-VP3以及pFHB-VP4。利用Bac-PAK快速滴定试剂盒测定重组杆状病毒滴度,并通过间接免疫荧光 (IFA)和蛋白质印迹法 (Western blot)鉴定重组蛋白的表达情况。结果显示,实验获得了较高滴度的重组杆状病毒,并且重组蛋白在杆状病毒感染的Sf9昆虫细胞中正确表达。将成功表达蛋白的重组杆状病毒pFHB-VP35、pFHB-VP3以及pFHB-VP4共感染Sf9细胞组装GCRV-VLPs,通过透射电镜 (EM)观察VLPs的组装情况。结果显示,GCRV-Ⅱ的3个蛋白在Sf9昆虫细胞中可以完成自我组装,形成与天然病毒结构形似的VLPs,直径为65~72 nm。本实验结果为进一步研制安全、高效的GCRV-VLPs疫苗奠定了基础。

     

    Abstract: In order to construct genotype II grass carp reovirus (GCRV) virus-like particulars (VLPs) based vaccines, the immunogenic GCRV-VP3/VP4/VP35 protein was assembled into GCRV-VLPs using baculovirus expression system (BEVS). The structural protein VP35 encoded by the segment S11 of GCRV-II was inserted into baculovirus vector pFastBacHTATM using BEVS, and the identified recombinant vector was transformed into DH10Bac competent cells to screen recombinant plasmid Bacmid-VP35. Recombinant baculovirus pFHB-VP35 was obtained by transfecting recombinant plasmid Bacmid-VP35, recombinant baculovirus pFHB-VP3 and pFHB-VP4 was obtained by transfecting recombinant plasmid Bacmid-VP3 and Bacmid-VP4 which have been successfully constructed in our laboratory. Then the titers of recombinant baculovirus were determined by Bac-PAK rapid titer kit and the expression of proteins was identified by IFA and Western blot. The results showed that high titers of pFHB-VP35, pFHB-VP3, and pFHB-VP4 were obtained, and the corresponding proteins were successfully expressed in infected Sf9 cells. GCRV-VLPs were assembled co-infection of Sf9 cells with pFBH-VP35, pFBH-VP3, and pFBH-VP4, and the GCRV-VLPs were identified by electron microscopy (EM). The results showed that the three proteins could self-assemble in Sf9 cells and formed VLPs with diameter of 65-72 nm similar with natural viruses. This study lays a foundation for development of novel vaccines for preventing the disease caused by GCRV genotype II.

     

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