Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America.
Animal Disease Research Unit, Agricultural Research Service, United States Department of Agriculture, Pullman, Washington, United States of America.
PLoS One. 2018 Jul 2;13(7):e0200130. doi: 10.1371/journal.pone.0200130. eCollection 2018.
Gammaherpesviruses in the genus Macavirus establish clinically unapparent persistent infections in reservoir species. Transmission of some of these viruses, including alcelaphine herpesvirus 1 (AlHV-1) and ovine herpesvirus 2 (OvHV-2), to clinically susceptible species in the order Artiodactyla can result in malignant catarrhal fever (MCF), a usually fatal lymphoproliferative disease. Serology can be used to identify MCF virus (MCFV)-infected carrier animals. However, all current serological assays utilize AlHV-1 antigens, thus none is specific for OvHV-2. In situations where sheep and other MCFV carriers are present, such as in zoos and game farms, an OvHV-2-specific assay would determine if OvHV-2 is present in the population. In this study, a recombinant protein containing a truncated OvHV-2 Ov8 glycoprotein was expressed and evaluated as a suitable target antigen to specifically detect OvHV-2 infection using an enzyme linked immunosorbent assay (ELISA). A competitive inhibition (CI)-ELISA that detects an epitope conserved among all MCFVs was used to categorize, as positive or negative, sera from 205 domestic sheep. The Ov8 assay showed 100% diagnostic sensitivity, 98.97% diagnostic specificity, 99.07% positive predictive value, and 100% negative predictive value and very high agreement (kappa = 0.990 and 95% CI = 0.971-1.000) with the CI-ELISA. Sera from animals infected with MCFVs other than OvHV-2 did not cross-react with Ov8 (100% negative predictive value). These data support the use of the Ov8 ELISA as an OvHV-2-specific diagnostic assay.
马卡里亚疱疹病毒属中的γ疱疹病毒在储存物种中建立了临床无症状的持续性感染。这些病毒中的一些，包括非洲牛瘟疱疹病毒 1（AlHV-1）和绵羊疱疹病毒 2（OvHV-2），在偶蹄目动物的临床易感物种中的传播可能导致恶性卡他热（MCF），这是一种通常致命的淋巴增生性疾病。血清学可用于识别 MCF 病毒（MCFV）感染的携带动物。然而，所有当前的血清学检测都利用 AlHV-1 抗原，因此没有一种是针对 OvHV-2 的特异性检测。在绵羊和其他 MCFV 携带者存在的情况下，如动物园和猎场，一种针对 OvHV-2 的特异性检测将确定该人群中是否存在 OvHV-2。在这项研究中，表达并评估了一种含有截断的 OvHV-2 Ov8 糖蛋白的重组蛋白，作为一种合适的靶抗原，用于使用酶联免疫吸附试验（ELISA）特异性检测 OvHV-2 感染。一种检测所有 MCFV 中保守表位的竞争抑制（CI）-ELISA 用于对来自 205 只绵羊的血清进行分类，分为阳性或阴性。Ov8 检测法显示出 100%的诊断敏感性、98.97%的诊断特异性、99.07%的阳性预测值和 100%的阴性预测值，以及与 CI-ELISA 非常高的一致性（kappa=0.990，95%置信区间=0.971-1.000）。除了 OvHV-2 以外的 MCFV 感染动物的血清与 Ov8 没有交叉反应（100%的阴性预测值）。这些数据支持使用 Ov8 ELISA 作为一种针对 OvHV-2 的特异性诊断检测方法。
