猪δ冠状病毒核衣壳蛋白新型线性B细胞表位的鉴定OA

In this study,ten previously established monoclonal antibodies(mAbs)against the nucleocapsid(N)protein of porcine deltacoronavirus(PDCoV)—6G10,5B11,3C9,4G2,2B2,3B3,4E11,5F6,6B5,and 7C8—were characterized for specificity and their corresponding antigenic epitopes were identified.The mAbs were first validated by Western-blot and indirect immunofluorescence assay(IFA).Epitope mapping was performed using sandwich ELISA and a series of truncated N protein constructs,followed by homology alignment and struc-tural analysis of the identified epitopes.Results demonstrated that all ten mAbs reacted specifically with both the recombinant N protein and native N protein expressed in PDCoV-infected LLC-PK1 cells.Epi-tope mapping revealed that mAb 3C9 recognized a distinct epitope,270GSPDYER276,while 3B3 and the other eight mAbs recognized the epitope 130TGDGPAQGFRV140.Homology and structural analyses indicated that both epitopes were highly conserved across PDCoV strains and shared considerable sequence similarity with certain avian deltacoronaviruses,but they exhibited low homology with other porcine coronaviruses,which confirmed the high specificity of the mAbs.This study successfully identified a novel linear B cell epitope of 130TGDG-PAQGFRV140 through the characterization of the antigenic epitopes of 3B3 and 3C9 mAbs,which provided a valuable foundation for further investigation into the structure and function of PDCoV N protein.