马传染性贫血病弱毒疫苗免疫马血清对同源和异源病毒株中和活性的研究

摘要

In order to evaluate the neutralizing activity of the sera from the attenuated vaccine-immunized horses against the homologous and heterologous equine infectious anemia virus (EIAV) strains,pseudoviruses carrying different EIAV envelopproteins from EIAVFDDV3-8,EIAVLN,EIAVUK,or EIAVYN were rescued by transfecting the Env recombinant expression plasmids packaging plasmid (pUK-gag-pol),and transfer vector (pONYS.1) in 293T cells.The pseudoviruses were incubated with vaccine immunized horses' sera (5# and 8#),and then seeded in ELR1-293T cell monolayer.By detecting the luciferase activity in cells,the serum neutralization titer against different enveloped viruses was calculated.The results showed that the horse sera neutralized the pseudo-viruses at different levels,as the order declined:pVR1012-FDDV3-8-Env,pVR1012-LN-Env,pVR1012-UK-Env,and pVR1012-YN-Env.Further analysis proved that there was a negative correlation between the neutralization ability of vaccineimmunized sera and the variation level of different EIAV strains Env compared with that of EIAV vaccine strain (5#,R2=0.99;8#,R2=0.96).Although the ability to neutralize heterologous strains was lower than that of homologous strains,the sera still had strong neutralization activities on heterologous strains,indicating that the Chinese EIAV attenuated vaccine strains could inducebroad spectnum neutralization antibody against different strains.%为评价马传染性贫血病毒(EIAV)弱毒疫苗免疫马血清对同源和异源病毒株的中和活性差异,本研究构建了不同EIAV株(EIAVFDV3-8、EIAVLN、EIAVUK和EIAVYN) Env的重组表达质粒,并将这些质粒与包装质粒(pUK-Gag-pol)及表达荧光素酶的转移质粒(pONY8.1)共转染293T细胞;将假病毒与疫苗免疫马(5#、8#)血清共孵育后接种于ELR1-293T细胞单层;通过检测细胞中荧光素酶活性,计算疫苗免疫马血清中和50％假病毒感染的血清稀释倍数,评价血清对病毒的中和活性.结果显示,疫苗免疫马血清对表达不同Env假病毒的中和滴度存在差异,从高到低依次是:pVR1012-FDDV-3-8-Env、pVR 1012-LN-Env、pVR1012-UK-Env、pVR 1012-YN-Env,而且免疫血清对不同病毒株的中和能力与不同病毒株Env的变异呈负相关(5#,R2=0.99;8#,R2=0.96).虽然免疫马血清中和异源病毒株的能力显著低于同源病毒株,但其对异源病毒株仍具有良好的中和作用,本研究结果表明中国EIAV弱毒疫苗可以激发抗不同病毒株的广谱中和抗体.