PRV变异株与疫苗株主要糖蛋白的免疫原性差异分析

Study on Immunogenicity Differences of the Major Glycoproteins between the Variant Strain and the Vaccine Strain of Pseudorabies Virus

本研究使用CRISPR/Cas9与HDR结合的技术,以疫苗株Bartha-K61和变异株JS-2012-ΔgE/gI为骨架,成功构建了gB基因互换的重组病毒BJB和JBJ、gC基因互换的重组病毒Bar-JSgC和JS-BargC、gD基因互换的重组病毒Bar-JSgD和JS-BargD。基因替换的重组病毒与其亲本病毒的体外生物学特性较为相似。其中,与亲本毒株JS-2012-ΔgE/gI相比,JS-BargC在PK-15细胞上的复制能力显著降低。小鼠免疫保护试验证明了gB替换能够显著改变Bartha-K61和JS-2012-ΔgE/gI的免疫原性,提示疫苗株免疫对变异株不保护现象与gB变异密切相关;gC和gD的变异在一定程度上改变了Bartha-K61的免疫原性。本研究为揭示PRV毒株间变异和免疫逃避机制提供了理论基础。

Using the technology of CRISPR/Cas9 combined with HDR,gB-substituted recombinant strains BJB and JBJ of Pseudorabies virus (PRV),gC-substituted recombinant strains PRV Bar-JSgC and JS-BargC,gD-substituted recombinant strains PRV Bar-JSgD and JS-BargD were successfully constructed based on the backbone strains Bartha-K61 and JS-2012-ΔgE/gI,respectively.The biological characteristics of the recombinant strains and its parental strains were similar in vitro.Among them,the replication ability of JS-BargC on PK-15 cell line was significantly reduced compared with the parental strain JS-2012-ΔgE/gI.The cross-immunoprotection test in mice showed that variations in gB contributed to immunogenic differences between PRV variant JS-2012 and Bartha-K61,which suggested that the poor-immunoprotection of the vaccine strain against variant strain JS-2012 was closely related to gB variations.Furthermore,the variations in gC and gD caused changes of immunogenicity of Bartha-k61 to some extent.This study provided an essential basis for revealing the variations between PRV strains and the immune escape mechanism.