Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan Province, P. R. China.
Sichuan Center for Animal Disease Prevention and Control, Chengdu, Sichuan Province, P. R. China.
PLoS Negl Trop Dis. 2023 Oct 23;17(10):e0011709. doi: 10.1371/journal.pntd.0011709. eCollection 2023 Oct.
Cystic echinococcosis (CE) is caused by the infection of Echinococcus granulosus sensu lato (E. granulosus s.l.), one of the most harmful zoonotic helminths worldwide. Infected dogs are the major source of CE transmission. While praziquantel-based deworming is a main measure employed to control dog infections, its efficacy is at times compromised by the persistent high rate of dog re-infection and the copious discharge of E. granulosus eggs into the environment. Therefore, the dog vaccine is a welcome development, as it offers a substantial reduction in the biomass of E. granulosus. This study aimed to use previous insights into E. granulosus functional genes to further assess the protective efficacy of six recombinant proteins in dogs using a two-time injection vaccination strategy.
We expressed and combined recombinant E. granulosus triosephosphate isomerase (rEgTIM) with annexin B3 (rEgANXB3), adenylate kinase 1 (rEgADK1) with Echinococcus protoscolex calcium binding protein 1 (rEgEPC1), and fatty acid-binding protein (rEgFABP) with paramyosin (rEgA31). Beagle dogs received two subcutaneous vaccinations mixed with Quil-A adjuvant, and subsequently orally challenged with protoscoleces two weeks after booster vaccination. All dogs were sacrificed for counting and measuring E. granulosus tapeworms at 28 days post-infection, and the level of serum IgG was detected by ELISA.
Dogs vaccinated with rEgTIM&rEgANXB3, rEgADK1&rEgEPC1, and rEgFABP-EgA31 protein groups exhibited significant protectiveness, with a worm reduction rate of 71%, 57%, and 67%, respectively, compared to the control group (P < 0.05). Additionally, the vaccinated groups exhibited an inhibition of worm growth, as evidenced by a reduction in body length and width (P < 0.05). Furthermore, the level of IgG in the vaccinated dogs was significantly higher than that of the control dogs (P < 0.05).
These verified candidates may be promising vaccines for the prevention of E. granulosus infection in dogs following two injections. The rEgTIM&rEgANXB3 co-administrated vaccine underscored the potential for the highest protective efficacy and superior protection stability for controlling E. granulosus infections in dogs.
包虫病（CE）是由细粒棘球绦虫（E. granulosus s.l.）感染引起的，它是世界上最具危害性的动物源性寄生虫之一。受感染的狗是 CE 传播的主要来源。尽管基于吡喹酮的驱虫是控制狗感染的主要措施，但由于狗持续高比例的再次感染和大量棘球蚴卵排放到环境中，其疗效有时会受到影响。因此，狗疫苗的发展是受欢迎的，因为它可以显著减少细粒棘球绦虫的生物量。本研究旨在利用先前对细粒棘球绦虫功能基因的了解，进一步评估在两次注射疫苗接种策略下，六种重组蛋白在狗中的保护效果。
我们表达并组合了重组细粒棘球蚴磷酸丙糖异构酶（rEgTIM）与 annexin B3（rEgANXB3）、腺嘌呤激酶 1（rEgADK1）与棘球蚴原头节钙结合蛋白 1（rEgEPC1），以及脂肪酸结合蛋白（rEgFABP）与副肌球蛋白（rEgA31）。比格犬接受两次皮下注射，并用 Quil-A 佐剂混合，在加强疫苗接种两周后口服感染原头节。所有狗在感染后 28 天被处死，以计算和测量棘球蚴绦虫，并通过 ELISA 检测血清 IgG 水平。
rEgTIM&rEgANXB3、rEgADK1&rEgEPC1 和 rEgFABP-EgA31 蛋白组的狗表现出显著的保护作用，与对照组相比，其绦虫减少率分别为 71%、57%和 67%（P<0.05）。此外，接种组的绦虫生长受到抑制，表现为体长和体宽减小（P<0.05）。此外，接种狗的 IgG 水平明显高于对照组（P<0.05）。
这些经过验证的候选疫苗在两次注射后可能是预防狗感染细粒棘球绦虫的有前途的疫苗。rEgTIM&rEgANXB3 联合疫苗强调了最高保护效果和控制狗感染细粒棘球绦虫的更优保护稳定性的潜力。
