School of Environmental and Rural Science, University of New England, Armidale, NSW 2351, Australia; College of Agriculture and Environmental Science, Arsi University, Asella, P.O.Box 193, Ethiopia.
CSIRO, Livestock & Aquaculture, F.D. McMaster Laboratory, Armidale, NSW 2350, Australia.
Vet Parasitol. 2022 Jan;301:109637. doi: 10.1016/j.vetpar.2021.109637. Epub 2021 Dec 8.
This study was conducted to investigate whether co-administration of Barbervax® (Bvax) with Haemonchus contortus surface larval antigen (HcsL3) would increase the protective efficacy and duration of protection against H. contortus infection in weaner Merino sheep. A total of 132 10-month-old weaned Merino ewe lambs were randomly allocated into six treatment groups (n = 22). Sheep were vaccinated four times with either Barbervax® (Bvax), H. contortus L3 surface larval antigen (HcsL3), combined vaccination (Bvax + HcsL3), Bvax + AlOH, HcsL3 + Saponin or remained as unvaccinated controls. Aluminium hydroxide (AlOH) and saponin adjuvants were included in HcsL3 and Bvax vaccines respectively. The first three vaccinations were given at 4 week intervals and the fourth vaccination provided as booster, 9 weeks later. All animals were treated with Zolvix™ (monepantel 25 mg/mL, Elanco) at the third vaccination and commencing two weeks later, artificially trickle infected with H. contortus L3. Worm egg count (WEC), packed cell volume (PCV), antibody titre and bodyweight were measured throughout the study as was specific antibody directed against each antigen using ELISA. The administration of Bvax and HcsL3, alone or in combination, induced an antibody response against HcsL3 but only the Bvax and the combined treatment elicited an antibody response to the Bvax antigen. The targeting of HcsL3 by each vaccine was confirmed by immunofluorescence staining of H. contortus L3. However, only the booster vaccination in the Bvax treatments reduced WEC to levels below untreated controls. The HcsL3 vaccine did not reduce WEC in this experiment and co-administration with Bvax did not improve the efficacy and duration of protection against H. contortus infection.
本研究旨在探讨在断奶美利奴羊中，同时给予 Barbervax®（Bvax）和 Haemonchus contortus 表面幼虫抗原（HcsL3）是否会增加对 H. contortus 感染的保护效力和保护持续时间。总共 132 只 10 月龄断奶美利奴母羊被随机分配到六个治疗组（n = 22）。羊用 Barbervax®（Bvax）、H. contortus L3 表面幼虫抗原（HcsL3）、联合疫苗（Bvax + HcsL3）、Bvax + AlOH、HcsL3 + 皂素或未接种疫苗进行四次免疫。氢氧化铝（AlOH）和皂素佐剂分别包含在 HcsL3 和 Bvax 疫苗中。前三次免疫接种间隔 4 周，第四次免疫接种作为加强针，9 周后进行。所有动物在第三次免疫接种时用 Zolvix™（monepantel 25 mg/mL，Elanco）进行治疗，并在两周后开始，人工滴注感染 H. contortus L3。在整个研究过程中，测量了蠕虫卵计数（WEC）、红细胞压积（PCV）、抗体滴度和体重，并使用 ELISA 测量了针对每种抗原的特异性抗体。Bvax 和 HcsL3 的单独或联合给药诱导了针对 HcsL3 的抗体反应，但只有 Bvax 和联合治疗诱导了针对 Bvax 抗原的抗体反应。通过对 H. contortus L3 进行免疫荧光染色，证实了每种疫苗对 HcsL3 的靶向作用。然而，只有 Bvax 治疗中的加强免疫接种将 WEC 降低到未处理对照以下的水平。在本实验中，HcsL3 疫苗并未降低 WEC，并且与 Bvax 联合使用并未提高对 H. contortus 感染的保护效力和保护持续时间。
