Haçariz O, Sayers G, McCullough M, Garrett M, O'Donovan J, Mulcahy G
Veterinary Sciences Centre, School of Agriculture, Food Science and Veterinary Medicine, College of Life Sciences, University College Dublin, Belfield, Dublin 4, Ireland.
Vaccine. 2009 Jan 1;27(1):45-50. doi: 10.1016/j.vaccine.2008.10.035. Epub 2008 Oct 31.
Fasciola hepatica infection causes significant clinical disease in ruminants. Current control methods, based on flukicidal drugs, are becoming less useful because of resistance in fluke populations. Vaccination would be a viable alternative, but as yet no vaccine to protect ruminants against liver fluke infection has been commercialised. Adjuvants can be used to enhance and promote protective immune responses by vaccines. In previous vaccination trials, we have observed a distinct adjuvant effect, or a degree of protection, in animals administered adjuvant alone in the absence of any specific F. hepatica antigen. Understanding this effect will be important for continuing efforts to develop vaccines effective against fasciolosis. This study investigated the effects of three adjuvants (Quil A, Freund's Incomplete and TiterMax Gold) on the course of experimental F. hepatica infection in 6-month-old sheep (n=33). At completion of the trial, all animals were necropsied to determine fluke burden and fluke weight. Quil A administration led to a significant reduction in faecal egg count (P<0.0001) and significantly higher parasite-specific serum antibody activity for all isotypes measured (P<0.01). This suggests that Quil A, which promotes a Th1 response, may be useful as an adjuvant in anti-Fasciola vaccines. Furthermore, it reinforces the results of our previous studies indicating that enhanced Th1 responsiveness to vaccine antigens is required to achieve protection against challenge by F. hepatica.
肝片吸虫感染会在反刍动物中引发严重的临床疾病。目前基于杀吸虫药物的控制方法，由于吸虫种群产生抗药性，其效用正逐渐降低。疫苗接种将是一种可行的替代方法，但迄今为止，尚无用于保护反刍动物免受肝吸虫感染的疫苗实现商业化。佐剂可用于增强和促进疫苗的保护性免疫反应。在之前的疫苗接种试验中，我们观察到在未使用任何特定肝片吸虫抗原的情况下，单独给予佐剂的动物出现了明显的佐剂效应或一定程度的保护作用。了解这种效应对于继续努力开发有效对抗肝片吸虫病的疫苗至关重要。本研究调查了三种佐剂（Quil A、弗氏不完全佐剂和TiterMax Gold）对6月龄绵羊（n = 33）实验性肝片吸虫感染过程的影响。试验结束时，对所有动物进行尸检以确定吸虫负荷和吸虫重量。给予Quil A导致粪便虫卵计数显著降低（P < 0.0001），并且所检测的所有同种型的寄生虫特异性血清抗体活性显著更高（P < 0.01）。这表明促进Th1反应的Quil A可能作为抗肝片吸虫疫苗的佐剂有用。此外，它强化了我们之前研究的结果，表明需要增强对疫苗抗原的Th1反应性才能实现对肝片吸虫攻击的保护。
