Precise mapping of two conserved minimal epitopes on the nucleocapsid protein of porcine epidemic diarrhea virus
Introduction Porcine epidemic diarrhea virus (PEDV) is a highly contagious enteric pathogen that causes severe diarrhea and high mortality in neonatal piglets, leading to substantial economic losses in the swine industry. The nucleocapsid (N) protein is highly conserved and abundantly expressed during infection, making it a suitable target for serological detection. Methods In this study, twomonoclonal antibodies (mAbs), C9 and G11, directed against the PEDV N protein were used to define minimal linear epitopes. A stepwise truncation approach based on overlapping recombinant fragments was applied to localize the antigenic regions. Results The results showed that mAb C9 and mAb G11 recognized the minimal epitopes 58RWRM61 and 15PLSL18, respectively. Sequence analysis indicated that both epitopes are highly conserved among representative PEDV strains from different genotypes. In addition, structural modeling suggested that these regions are exposed on the surface of the N protein, consistent with their accessibility to antibody binding. Discussion These findings provide a more precise characterization of antigenic sites within the PEDVNprotein andmay be useful for the development of specific and reliable serological assays.