Jayaraj Rama, Kumarasamy Chellan, Norbury Luke, Piedrafita David, Smooker Peter
Yellow 1.1.05, Charles Darwin University, Ellengowan Drive, Darwin, Northern Territory, 0909, Australia.
University of Adelaide, North Terrace Campus, Adelaide, South Australia, 5005, Australia.
Vet Parasitol. 2019 Mar;267:90-98. doi: 10.1016/j.vetpar.2019.01.010. Epub 2019 Feb 16.
The immunogenicity and efficacy of Fasciola DNA vaccines have not yet been comprehensively summarised in the form of a systematic review and meta-analysis. Though multiple vaccine studies with respect to Fasciola vaccines exist, the variance in the experimental parameters has made comparison difficult. We conducted a bibliographic database search in Scopus, PubMed, Science Direct, Cochrane Library, EMBASE and Web of Science databases, limited to publications from 1998 to 2017. The key words: Liver fluke, Fasciola hepatica, Fasciola gigantica, DNA vaccination, and immunogenicity were used in combination to form search strings. A total of 4760 studies were identified after initial screening, of which 14 qualified for systematic review and 7 for meta-analysis. The mean Odds Ratio (OR) for all studies was 0.565 (95% confidence interval (CI) of 0.293 to 1.087), which means the percentage of protection in terms of decreased fluke burden in animals vaccinated with DNA vaccines was 43.5%. A moderate protective efficacy was observed for cysteine protease and phosphoglycerate kinase vaccine antigen candidates (pooled OR and 95% CI, [0.542; 0.179-1.721] and [0.616; 0.219-1.735], respectively). Vaccine effectiveness was observed in individual studies and cohorts; however, the overall pooled efficacy for all vaccine candidates was found to be non-significant. Despite multiple individual studies showing promising results for various DNA vaccine candidates against fascioliasis, the pooled studies showed the non-significant effect of the vaccine formulations against fluke burden, and displayed minimal protective efficacy against Fasciola infection. Though promising results are observed in isolated studies, further animal trials with standardised experimental parameters are required to develop new vaccine candidates effective against Fasciola.
肝片吸虫DNA疫苗的免疫原性和有效性尚未以系统评价和荟萃分析的形式进行全面总结。尽管存在多项关于肝片吸虫疫苗的研究，但实验参数的差异使得比较变得困难。我们在Scopus、PubMed、Science Direct、Cochrane图书馆、EMBASE和Web of Science数据库中进行了文献数据库搜索，搜索范围限于1998年至2017年的出版物。使用关键词“肝吸虫”、“肝片吸虫”、“巨片吸虫”、“DNA疫苗接种”和“免疫原性”组合形成搜索字符串。初步筛选后共识别出4760项研究，其中14项符合系统评价标准，7项符合荟萃分析标准。所有研究的平均比值比（OR）为0.565（95%置信区间（CI）为0.293至1.087），这意味着接种DNA疫苗的动物体内吸虫负担减轻方面的保护百分比为43.5%。对半胱氨酸蛋白酶和磷酸甘油酸激酶疫苗候选抗原观察到中等程度的保护效力（合并OR和95%CI分别为[0.542；0.179 - 1.721]和[0.616；0.219 - 1.735]）。在个别研究和队列中观察到了疫苗有效性；然而，发现所有疫苗候选物的总体合并效力不显著。尽管多项个别研究显示各种DNA疫苗候选物抗片形吸虫病有前景的结果，但汇总研究显示疫苗制剂对吸虫负担的影响不显著，且对肝片吸虫感染显示出最小的保护效力。尽管在个别研究中观察到了有前景的结果，但需要进一步进行具有标准化实验参数的动物试验，以开发出有效抗肝片吸虫的新疫苗候选物。
