Muratore Elvira, Bertolotti Luigi, Nogarol Chiara, Caruso Claudio, Lucchese Laura, Iotti Bryan, Ariello Dario, Moresco Angela, Masoero Loretta, Nardelli Stefano, Rosati Sergio
Department of Veterinary Science, University of Torino, Italy.
Istituto Zooprofilattico Sperimentale di Piemonte Liguria e Valle d'Aosta, Torino, Italy.
Vet Immunol Immunopathol. 2017 Mar;185:1-6. doi: 10.1016/j.vetimm.2017.01.003. Epub 2017 Jan 24.
Infectious Bovine Rhinotracheitis (IBR) occurs worldwide, requiring significant resources for eradication programs or surveillance purposes. The status of infection is usually detected by serological methods using the virus neutralization test (VNT) or enzyme-linked immunosorbent assay (ELISA) on individual sera. The gE DIVA (Differentiating Infected from Vaccinated Animals) vaccines approach, adopted in order to reduce the virus circulation and prevent clinical signs, have tightened the range of available methods for the serological diagnosis. Different gE blocking ELISA could be performed to detect specific antibodies in sera of infected or whole virus-vaccinated animals but with less sensitivity if applied to bulk milk samples, especially in marker-vaccinated herds. A new rec-gE ELISA was recently developed in Italy and applied with good performances on blood serum samples. The present paper focuses on the application of a rapid protocol for purification/concentration of immunoglobulin G (IgG) from bulk milk and on the use of the new rec-gE indirect ELISA. The study involved three different partners and 225 herds (12,800 lactating cows) with different official IBR diagnostic statuses. The diagnostic specificity of the method was demonstrated closed to 100% while the diagnostic sensitivity was strictly related to the herd-seroprevalence. Considering 2.5% as the limit of detection of within-herd seropositivity prevalence, the diagnostic sensitivity showed by the proposed method was equal to 100%. A single reactivation of a whole strain vaccine in an old cow was detected inside a group of 67 lactating cows, showing the field applicability of the method.
牛传染性鼻气管炎（IBR）在全球范围内均有发生，根除计划或监测工作需要投入大量资源。感染状况通常通过血清学方法进行检测，即对个体血清进行病毒中和试验（VNT）或酶联免疫吸附测定（ELISA）。为减少病毒传播并预防临床症状而采用的gE DIVA（区分感染动物和接种疫苗动物）疫苗方法，限制了血清学诊断可用方法的范围。可以进行不同的gE阻断ELISA来检测感染动物或接种全病毒疫苗动物血清中的特异性抗体，但应用于批量牛奶样本时灵敏度较低，尤其是在接种标记疫苗的牛群中。意大利最近开发了一种新的重组gE ELISA，并在血清样本上取得了良好的应用效果。本文重点介绍了一种从批量牛奶中快速纯化/浓缩免疫球蛋白G（IgG）的方法以及新型重组gE间接ELISA的应用。该研究涉及三个不同的合作伙伴和225个牛群（12,800头泌乳奶牛），这些牛群具有不同的IBR官方诊断状态。该方法的诊断特异性接近100%，而诊断灵敏度与牛群血清阳性率密切相关。以2.5%作为牛群内血清阳性率的检测下限，该方法的诊断灵敏度为100%。在一组67头泌乳奶牛中检测到一头老龄奶牛体内的全病毒疫苗出现了一次再激活情况，表明该方法具有现场适用性。
