狂犬病病毒不同毒株糖蛋白免疫原性的比较研究

Comparative study on the immunogenicity of different rabies virus glycoproteins

我们之前研究发现,狂犬病病毒(RABV)BD06株与SRV9株糖蛋白的免疫原性存在明显差异。为进一步探究其他不同毒株RABV糖蛋白的免疫原性,利用来源于5种狂犬病病毒株的糖蛋白基因分别构建了以杆状病毒为载体的重组病毒Ac-BD06-G、Ac-CVS-11-G、Ac-Flury-LEP-G、Ac-ERA-G、Ac-SRV9-G,并用其表达的等量糖蛋白分别免疫小鼠,之后进行中和抗体水平测定和脑内攻毒保护试验。结果发现,一定量的不同毒株RABV糖蛋白诱导小鼠产生的VNA水平存在差异,由高到低依次为Ac-Flury-LEP-G、Ac-CVS-11-G、Ac-BD06-G、Ac-ERA-G、Ac-SRV9-G。此外,针对标准毒CVS-24脑内攻毒,不同毒株糖蛋白提供的保护率也存在差异,在Ac-Flury-LEP-G、Ac-CVS-11-G、Ac-BD06-G均为100%,而在Ac-ERA-G仅为6.7%,在Ac-SRV9-G则为0。结果显示,重组糖蛋白的免疫原性和保护性与其来源毒株本身的毒力强弱不存在线性关系,与攻击毒株之间核苷酸同源性的高低也没有直接关系。但总的来说,强毒株糖蛋白重组杆状病毒的免疫原性均明显好于弱毒株,并能提供更好的攻毒保护效果。据此推测,强毒糖蛋白基因更适合作为重组疫苗候选基因。本研究结果为RABV亚单位疫苗或者重组活载体疫苗研究过程中目的基因的选择提供了一定的参考和理论依据。

The immunogenicity of rabies virus（RABV） glycoproteins from a street isolate BD06 has been proved to be significantly superior to the vaccine strain SRV9 in our previous study. However, it is unclear whether the glycoproteins of other rabies virus strains exists differences in inducing immunogenicity.In this study,five recombinant baculoviruses,i.e.,Ac-BD06-G,Ac-CVS-11-G,Ac-FluryLEP-G,Ac-ERA-G,Ac-SRV9-G,expressing glycoproteins derived from BD06,CVS-11,Flury-LEP,ERA,SRV9,respectively,were constructed and examined for their immunogenicity in mice.Four weeks after inoculation,the viral neutralization antibody was tested and the average titer from high to low was Ac-Flury-LEPGAc-CVS-11-GAc-BD06-GAc-ERA-GAc-SRV9-G.Eight weeks post vaccination,the mice were all challengedby100LD50CVS-24,andtheprotectionrates were 100% in Ac-Flury-LEP-G, Ac-CVS-11-G and Ac-BD06-G groups, whereas the protection rates in Ac-ERA-G and Ac-SRV9-G groups were only 6.7% and 0,respectively.It is apparent that the virulent rabies virus glycoprotein is more suitable for recombinant vaccine development.This result provides important data in selecting the glycoprotein-encoding genes whenconstructing a new rabies vaccine.