DNA vaccination in large animals has often been associated with poor immunogenicity, consequently several approaches have been evaluated to enhance its efficacy. Here, we tested a cDNA encoding a phosphoglycerate kinase from Fasciola hepatica (cDNA-FhPGK/pCMV) as a vaccine against ovine fasciolosis and investigated whether a DNA prime/protein boost regime or CTLA-4 (cytotoxic lymphocyte antigen 4) mediated targeting improved DNA vaccine efficacy. No statistically significant differences in the cellular responses were seen in either vaccine trial when compared with the respective control groups. However, specific antibody responses were considerably enhanced in DNA primed/protein boosted sheep, but not among CTLA-4 targeted cDNA-FhPGK/pCMV vaccinated animals. Nevertheless, increased titers of specific IgG1 did not contribute to protection against infection, with no differences in liver fluke recoveries reported. If DNA vaccines against fasciolosis in target species are to reach the market one day, more research in this area is needed.

中文翻译：

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DNA初免/蛋白质加强方案和CTLA-4介导的靶向治疗未能改善绵羊编码Fasciola hepatica磷酸甘油酸激酶的DNA疫苗的效力。

大型动物中的DNA疫苗接种通常与不良的免疫原性有关，因此，已评估了几种方法来增强其效力。在这里，我们测试了编码来自Fasciola hepatica hepatica的磷酸甘油酸激酶的cDNA（cDNA-FhPGK / pCMV）作为抗羊膜炎的疫苗，并研究了DNA初免/蛋白加强方案还是CTLA-4（细胞毒性淋巴细胞抗原4）介导的靶向改良DNA疫苗功效。与相应对照组相比，在任一疫苗试验中均未观察到细胞应答的统计学显着差异。然而，在DNA初免/蛋白质增强的绵羊中，特异性抗体反应显着增强，但在接种了CTLA-4的cDNA-FhPGK / pCMV免疫动物中却没有。不过，特异性IgG1滴度的增加并没有帮助预防感染，据报道肝吸虫的回收率没有差异。如果针对目标物种中的片虫病的DNA疫苗有一天要投放市场，则需要在这一领域进行更多的研究。