Eosinophils are prominent effector cells in immune responses against gastrointestinal nematode infections in ruminants, but their in vivo role has been hard to establish in large animals. Interleukin-5 is a key cytokine in the induction and stimulation of anti-parasitic eosinophil responses. This study attempted to modulate the eosinophil response in sheep through vaccination with recombinant interleukin-5 (rIL-5) and determine the effect on subsequent Haemonchus contortus infection. Nematode-resistant Canaria Hair Breed (CHB) sheep vaccinated with rIL-5 in Quil-A adjuvant, had lower blood eosinophil counts and higher mean worm burdens than control sheep vaccinated with Quil-A adjuvant alone. In addition, adult worms in IL-5-vaccinated sheep were significantly longer with higher eggs in utero in female worms, supporting an active role of eosinophils against adult parasites in CHB sheep. These results confirm that eosinophils can play a direct role in effective control of H contortus infection in sheep and offer a new approach to study immune responses in ruminants.

中文翻译：

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通过对绵羊嗜酸性粒细胞应答的白介素5调节，增加了对捻转血矛线虫感染的敏感性。

嗜酸性粒细胞是针对反刍动物胃肠道线虫感染的免疫反应中的重要效应细胞，但在大型动物中很难确立其体内作用。白介素5是诱导和刺激抗寄生虫嗜酸性粒细胞应答的关键细胞因子。这项研究试图通过用重组白介素5（rIL-5）进行疫苗接种来调节绵羊的嗜酸性粒细胞应答，并确定其对随后的弯曲变形杆菌的影响。在单独的Quil-A佐剂中接种了rIL-5的耐线虫的Canaria毛发（CHB）绵羊比单独接种Quil-A佐剂的对照羊具有较低的嗜酸性粒细胞计数和较高的平均蠕虫负担。此外，接种IL-5疫苗的绵羊的成虫比雌虫的子宫内卵长得多，卵长得多，支持嗜酸性粒细胞对CHB绵羊中成虫的积极作用。这些结果证实，嗜酸性粒细胞可以在绵羊的控制变形中有效发挥直接作用，并为研究反刍动物的免疫反应提供了一种新方法。