Wang Dongsheng, Yu Ruiming, Zhang Liping, Zhang Zhongwang, Zhou Peng, Liu Xia, Guo Huichen, Pan Li, Du Xiaohua, Liu Xinsheng
State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046, China; Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou, 730046, China; College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, 730070, China.
State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046, China; Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou, 730046, China.
Virology. 2025 Sep;610:110625. doi: 10.1016/j.virol.2025.110625. Epub 2025 Jul 11.
Porcine epidemic diarrhea virus (PEDV) and porcine deltacoronavirus (PDCoV) coronaviruses cause highly similar histopathological damage and clinical symptoms, and often appear as mixed infections in clinic, leading to great economic losses in the pig industry. Previous studies have demonstrated a certain degree of serological cross-reactivity between PDCoV and PEDV. However, the antigens and crucial epitopes contributing to serological cross-reactivity remain unclear. In this study, the specific viral antigen and crucial epitopes leading to serological cross-reactivity between PDCoV and PEDV were investigated. The nucleocapsid (N) protein was the contributing viral antigen. Truncation and mutation of the PDCoV N protein revealed that the region for serological cross-reactivity was located in the N-terminal domain. The crucial epitopes were amino acid aa19-62, aa79-91, aa102-196, and aa285-342. In addition, these crucial epitopes were highly homologous between the N proteins of PDCoV and other coronaviruses, suggesting that these sites may be the crucial epitopes inducing serological cross-reactivity between different coronaviruses. Moreover, an indirect ELISA capable of specifically differentiating PDCoV and PEDV sera was established by virtue of the C-terminal-truncated portion of N protein, which had low serological cross-reactivity. In conclusion, the main antigen and crucial epitopes leading to serological cross-reactivity between PDCoV and PEDV were identified. The specific ELISA created in this study provided important clues and effective methods for subsequent establishment of the diagnostic methods for PDCoV and PEDV, as well as effective differentiation between them in clinical practice.
猪流行性腹泻病毒（PEDV）和猪三角洲冠状病毒（PDCoV）可引起高度相似的组织病理学损伤和临床症状，且在临床上常表现为混合感染，给养猪业造成巨大经济损失。先前的研究已证明PDCoV和PEDV之间存在一定程度的血清学交叉反应。然而，导致血清学交叉反应的抗原和关键表位仍不清楚。在本研究中，对导致PDCoV和PEDV血清学交叉反应的特异性病毒抗原和关键表位进行了研究。核衣壳（N）蛋白是起作用的病毒抗原。PDCoV N蛋白的截短和突变表明，血清学交叉反应区域位于N端结构域。关键表位为氨基酸aa19 - 62、aa79 - 91、aa102 - 196和aa285 - 342。此外，这些关键表位在PDCoV与其他冠状病毒的N蛋白之间高度同源，表明这些位点可能是诱导不同冠状病毒间血清学交叉反应的关键表位。而且，利用血清学交叉反应较低的N蛋白C端截短部分建立了一种能够特异性区分PDCoV和PEDV血清的间接ELISA。总之，确定了导致PDCoV和PEDV血清学交叉反应的主要抗原和关键表位。本研究建立的特异性ELISA为后续建立PDCoV和PEDV的诊断方法以及在临床实践中有效区分它们提供了重要线索和有效方法。
