Key Laboratory of Animal Disease Diagnostics and Immunology, Ministry of Agriculture, MOE International Joint Collaborative Research Laboratory for Animal Health & Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China.
Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China.
Viruses. 2024 Mar 9;16(3):424. doi: 10.3390/v16030424.
Porcine epidemic diarrhea virus (PEDV) is a highly pathogenic swine coronavirus that causes diarrhea and high mortality in piglets, resulting in significant economic losses within the global swine industry. Nonstructural protein 3 (Nsp3) is the largest in coronavirus, playing critical roles in viral replication, such as the processing of polyproteins and the formation of replication-transcription complexes (RTCs). In this study, three monoclonal antibodies (mAbs), 7G4, 5A3, and 2D7, targeting PEDV Nsp3 were successfully generated, and three distinct linear B-cell epitopes were identified within these mAbs by using Western blotting analysis with 24 truncations of Nsp3. The epitope against 7G4 was located on amino acids 31-TISQDLLDVE-40, the epitope against 5A3 was found on amino acids 141-LGIVDDPAMG-150, and the epitope against 2D7 was situated on amino acids 282-FYDAAMAIDG-291. Intriguingly, the epitope 31-TISQDLLDVE-40 recognized by the mAb 7G4 appears to be a critical B-cell linear epitope due to its high antigenic index and exposed location on the surface of Nsp3 protein. In addition, bioinformatics analysis unveiled that these three epitopes were highly conserved in most genotypes of PEDV. These findings present the first characterization of three novel linear B-cell epitopes in the Nsp3 protein of PEDV and provide potential tools of mAbs for identifying host proteins that may facilitate viral infection.
猪流行性腹泻病毒（PEDV）是一种高致病性猪冠状病毒，可导致仔猪腹泻和高死亡率，给全球养猪业造成重大经济损失。非结构蛋白 3（Nsp3）是冠状病毒中最大的蛋白，在病毒复制中发挥关键作用，如多蛋白的加工和复制转录复合物（RTCs）的形成。在这项研究中，成功产生了针对 PEDV Nsp3 的三种单克隆抗体（mAb），7G4、5A3 和 2D7，并通过 Western blot 分析 24 个 Nsp3 截断物，鉴定出这三种 mAb 中的三个不同的线性 B 细胞表位。针对 7G4 的表位位于氨基酸 31-TISQDLLDVE-40，针对 5A3 的表位位于氨基酸 141-LGIVDDPAMG-150，针对 2D7 的表位位于氨基酸 282-FYDAAMAIDG-291。有趣的是，mAb 7G4 识别的表位 31-TISQDLLDVE-40 似乎是一个关键的 B 细胞线性表位，因为它具有较高的抗原指数和位于 Nsp3 蛋白表面的暴露位置。此外，生物信息学分析表明，这些三个表位在 PEDV 的大多数基因型中高度保守。这些发现首次描述了 PEDV Nsp3 蛋白中的三个新的线性 B 细胞表位，并为鉴定可能促进病毒感染的宿主蛋白提供了潜在的 mAb 工具。
