基于重组水疱性口炎病毒载体的寨卡疫苗构建及免疫原性评价

Construction and immunogenicity of Zika vaccine based on VSV vector

目的建立表达寨卡病毒E蛋白或含prM蛋白的G蛋白缺失型重组水疱性口炎病毒(rVSV)载体疫苗,评价其免疫效果。方法选取E蛋白或含prM蛋白基因,分别构建入prVSVΔG和prVSV骨架质粒,通过反向遗传学操作得到2种缺失VSV-G蛋白的重组病毒疫苗(rVSV△G-E、rVSV△G-prM-2A-E)和2种含VSV-G蛋白的重组病毒疫苗(rVSV-E、rVSV-prM-2A-E),免疫BALB/c小鼠后进行体液免疫及细胞免疫水平检测,比较4种重组病毒疫苗免疫差异。结果rVSV△G-prM-2A-E免疫后诱导产生的特异性抗体与rVSV-prM-2A-E免疫后抗体水平相当(P>0.05),但显著高于rVSV△G-E免疫组(P<0.05);rVSV△G-prM-2A-E免疫诱导产生的中和抗体略高于rVSV△G-E和rVSVE免疫组,但低于rVSV-prM-2A-E免疫组;4种重组疫苗免疫后能有效诱导细胞分泌淋巴细胞因子白细胞介素-2(IL-2)、γ-干扰素(IFN-γ)产生,但诱导产生的IFN-γ水平无显著差异(P>0.05);rVSV△G-prM-2A-E及rVSV△G-E的扩增需要添加VSV-G。结论提供额外的VSV-G可成功包装并扩增rVSV△G-prM-2A-E,且该疫苗诱导产生较高中和抗体及细胞免疫反应,可进一步研发成实用疫苗。

Objective To establish the G protein deficient recombinant vesicular stomatitis virus(VSV)vaccines expressing the Zika virus E protein and to investigate their immunological features.Methods The E or prM gene was used to construct prVSVΔG and prVSV backbone plasmids.The prM and E genes were ligated with the auto-cleaved 2 A sequence(FMDV-2 A)of foot-and-mouth disease virus.The plasmids were cotransfected with the helper plasmid and the scaffold vector before two virus vaccines without VSV-G(rVSVΔG-E and rVSVΔG-prM-2 A-E)and two vaccines with VSV-G(rVSV-E and rVSV-prM-2 A-E)were obtained.The vaccines were immunized into BALB/c mice and the differences of their humoral and cellular immune titers were tested.Results The level of rVSVΔG-prM-2 A-E immune-induced specific antibody was comparable to that of rVSV-prM-2 A-E(P>0.05),and significantly higher than that of rVSVΔG-E immunized group(P<0.05).The rVSVΔG-prM-2 A-E immune-induced neutralizing antibody was slightly higher than that induced by rVSVΔG-E and rVSV-E,and lower than that induced by rVSV-prM-2 A-E.The four recombinant vaccines effectively induced high cell secretion of lymphocyte factors IL-2 and IFN-γ,but IFN-γshowed no significant difference between the groups(P>0.05).VSV-G was required in the amplification of rVSV△G-prM-2 A-E and rVSV△G-E.Conclusion The addition of VSV-G can help the package of rVSV△G-prM-2 A-E and rVSV△G-E vaccine,which induces high neutralizing antibodies and cellular immune responses.This vaccine could be further developed into a practical vaccine.