Comparative Study on the Immunogenicity and Efficacy of Different Post-exposure Intramuscular Rabies Vaccination Regimens in China

Objective This study aimed to compare the current Essen rabies post-exposure immunization schedule(0-3-7-14-28)in China and the simple 4-dose schedule(0-3-7-14)newly recommended by the World Health Organization in terms of their safety,efficacy,and protection.Methods Mice were vaccinated according to different immunization schedules,and blood was collected for detection of rabies virus neutralizing antibodies(RVNAs)on days 14,21,28,35,and 120after the first immunization.Additionally,different groups of mice were injected with lethal doses of the CVS-11 virus on day 0,subjected to different rabies immunization schedules,and assessed for morbidity and death status.In a clinical trial,185 rabies-exposed individuals were selected for post-exposure vaccination according to the Essen schedule,and blood was collected for RVNAs detection on days 28and 42 after the first immunization.Results A statistically significant difference in RVNAs between mice in the Essen and 0-3-7-14 schedule groups was observed on the 35th day(P<0.05).The groups 0-3-7-14,0-3-7-21,and 0-3-7-28 showed no statistically significant difference(P>0.05)in RVNAs levels at any time point.The post-exposure immune protective test showed that the survival rate of mice in the control group was 20%,whereas that in the immunization groups was 40%.In the clinical trial,the RVNAs positive conversion rates on days 28(14 days after 4 doses)and 42(14 days after 5 doses)were both 100%,and no significant difference in RVNAs levels was observed(P>0.05).Conclusion The simple 4-dose schedule can produce sufficient RVNAs levels,with no significant effect of a delayed fourth vaccine dose(14–28 d)on the immunization potential.

Establishment and Preliminary Application of a Rapid Fluorescent Focus Inhibition Test (RFFIT) for Rabies Virus

The World Health Organization (WHO) standard assay for determining levels of the rabies virus neutralization antibody (RVNA) is the rapid fluorescent focus inhibition test (RFFIT), which is used to evaluate the immunity effect after vaccination against rabies. For RFFIT, CVS-11 was used as the challenge virus, BSR cells as the adapted cells, and WHO rabies immunoglobulin (WHO STD) as the reference serum in this study. With reference to WHO and Pasteur RFFIT procedures, a micro-RFFIT procedure adapted to our laboratory was produced, and its specificity and reproducibility were tested. We tested levels of RVNA in human serum samples after immunization with different human rabies vaccines (domestic purified Vero cell rabies vaccine (PVRV) and imported purified chick embryo cell vaccine (PCECV)) using different regimens (Zagreb regimen and Essen regimen). We analyzed the levels of RVNA, and compared the immune efficacy of domestic PVRV and imported PCECV using different immunization regimens. The results showed that the immune efficacy of domestic PVRV using the Zagreb regimen was as good as that of the imported PCECV, but virus antibodies were generated more rapidly with the Zagreb regimen than with the Essen regimen. The RFFIT procedure established in our laboratory will enhance the comprehensive detection ability of institutions involved in rabies surveillance in China.

RFFIT、FAVN、ELISA及狂犬病中和抗体检测试剂盒对狂犬病抗体检测的比较研究

为了比较RFFIT、FAVN、ELISA及狂犬病中和抗体检测试剂盒(RVNA Kit)等四种方法对狂犬病抗体的检测效果,对65份狂犬病疫苗免疫前、免疫后临床血清样本,分别使用RFFIT、FAVN、ELISA及RVNA Kit方法对狂犬病病毒特异性抗体进行测定,并对检测结果的阳性符合率、相关性及重复性进行分析。检测结果显示,RFFIT、FAVN及RVNA kit的阳性符合率为100%,三种方法与ELISA试剂盒的阳性符合率为95.38%,对0.5IU/mL^10IU/mL的血清样本进行阳性符合率分析显示,四种方法的阳性符合率为100%;相关性研究结果表明,RFFIT、FAVN及RVNA Kit之间任意两种方法检测结果的相关系数均超过0.97,但ELISA与其他三种方法检测结果的相关系数均低于0.86;同一份样品的重复性检验结果显示,RVNA Kit和ELISA比RFFIT和FAVN具有更好的重复性,而RVNA Kit的重复性最好,其变异系数仅6%。研究结果表明,RFFIT、FAVN及RVNA Kit等三种方法可通用于血清中抗狂犬病病毒中和抗体的检测,而ELISA检测结果与中和抗体效价有一定差距,但在经过优化、校验后ELISA也可以在有效范围内用于狂犬病抗体的检测。

基于狂犬病病毒CVS-11假病毒的中和抗体检测新技术及初步应用

目的建立一种可替代快速荧光灶抑制试验（RFFIT法）的简易高通量狂犬病病毒中和抗体（RVNA）检测技术。方法我们构建了表达荧光素酶报告基因与CVS-11包膜蛋白的狂犬病病毒假病毒，建立了狂犬病病毒中和抗体检测技术（改良RFFIT方法），与标准RFFIT方法结果平行比较，并进一步应用于北京地区宠物犬与饲养人群血清中和抗体检测。结果改良RFFIT方法与标准RFFIT方法平行检测的46份待检血清与5份阴性参比血清，符合率为100％，且使用CVS-11假病毒测得的样品RVNA数值与标准RFFIT所得数值高度相关（n=46，r=0．94，P〈0．0001）。改良RFFIT方法用于北京地区宠物犬与饲养人群血清中RVNA滴度测定，均为阳性，其平均IU值为33．01IU／ml。结论基于狂犬病病毒CVS-11假病毒的中和抗体检测技术简易高效，可替代传统RFFIT方法。本研究中北京地区宠物犬与饲养人群91份样本均可检出明显的狂犬病病毒保护性中和抗体。