Immunogenicity in sheep of Uruguayan commercial vaccines against bovine alphaherpesvirus 1, 5 and bovine pestiviruses

ABSTRACT: The serological responses induced by four commercial inactivated Uruguayan vaccines against bovine alphaherpesviruses (BoHV)-1 and -5 and bovine pestiviruses (BVDV-1, BVDV-2, and HoBiPeV) were evaluated in sheep. Thirty-seven sheep were immunized twice (day 0 and 25) and their serum samples were tested at different intervals (days 0, 25, 40, 60, and 90) post-vaccination (PV). Among the four vaccines tested, only one (G4) could induce the production of moderate neutralizing antibody titers against BoHV-1 and -5 and BVDV-1 and -2. The G3 vaccine showed a neutralizing serological response against the bovine alphaherpesviruses only. The G1 and G2 vaccines produced extremely low levels of antibodies in a few vaccinated animals only (geometric mean titers (GMT) 2.2). Similar levels of immunological responses were induced by the G4 vaccine against BoHV-1 and -5, and titers of neutralizing antibodies induced in approximately 70% of the animals are known to confer protection (GMT > 8). For bovine pestiviruses, the vaccine stimulated response of G4 against BVDV-2 was higher compared to that against BVDV-1, and extremely low for HoBiPeV. The peak of neutralizing antibodies to BoHV-1 and BVDV-1 was observed on days 40 and 60 PV, respectively. Thereafter, a remarkably decrease in neutralizing antibody response was observed at day 90 PV. These results demonstrated that tested commercial Uruguayan vaccines did not induce a serological response of adequate magnitude and duration. Thus, it is important to periodically review formulations and compositions of commercial vaccines against bovine alphaherpesviruses and pestiviruses.

摘要：本研究评估了四款乌拉圭市售灭活疫苗针对牛α疱疹病毒（bovine alphaherpesviruses, BoHV）-1型、-5型以及牛瘟病毒属病毒（bovine pestiviruses）-1型（BVDV-1）、-2型（BVDV-2）与HoBiPeV的血清学应答效果，受试对象为绵羊。37只绵羊于免疫后（post-vaccination, PV）第0天和第25天接受两次免疫，并分别在PV第0、25、40、60和90天采集血清样本进行检测。在所测试的四款疫苗中，仅G4疫苗可诱导针对BoHV-1、-5型以及BVDV-1、-2型的中等水平中和抗体滴度。G3疫苗仅可诱导针对牛α疱疹病毒的中和血清学应答。G1与G2疫苗仅在少数免疫绵羊体内诱导出极低水平的抗体，其几何平均滴度（geometric mean titers, GMT）仅为2.2。G4疫苗针对BoHV-1与-5型诱导的免疫应答水平相近，且约70%受试动物体内产生的中和抗体滴度（GMT＞8）已被证实可提供免疫保护。针对牛瘟病毒属病毒类，G4疫苗针对BVDV-2的免疫应答水平高于BVDV-1型，而针对HoBiPeV的应答水平极低。针对BoHV-1与BVDV-1的中和抗体峰值分别出现在PV第40天和第60天，随后在PV第90天中和抗体应答水平出现显著下降。本研究结果显示，本次测试的乌拉圭市售疫苗均未诱导出具有足够强度与持续时长的血清学应答。因此，定期审查针对牛α疱疹病毒与牛瘟病毒属病毒的市售疫苗的配方与组分，具有重要意义。