Antigenicity, epitope mapping, and intracellular distribution of the NSP7α protein of porcine reproductive and respiratory syndrome virus

• Published in: International journal of biological macromolecules 2024-04, Vol.265 (Pt 1), p.130944-130944, Article 130944
• Main Authors: Wang, Tao, Xia, Da-Song, Tian, Xiao-Xiao, Yang, Yong-Bo, An, Tong-Qing
• Format: Article
• Language: English
• Subjects: Antigenicity; Epitope; Intracellular distribution; NSP7α; PRRSV
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2024.130944

Porcine reproductive and respiratory syndrome virus (PRRSV) is an important pathogen that causes huge economic losses to the global pig industry. Nonstructural protein 7α (NSP7α) of PRRSV is highly conserved among different lineages of PRRSV and could be a potential target for the development of detection methods. In this study, NSP7α was expressed in prokaryote (Escherichia coli) and purified. An NSP7α-ab-ELISA detection method was established, the NSP7α-ab-ELISA has 93.1 % coincidence rate with IDEXX PRRS X3 ab test kit. NSP7α antibody was detected in pig serum by ELISA 14 days following PRRSV infection. Three monoclonal antibodies (4H9, 3F2, and C10) against NSP7α prepared by a hybridoma technique were used for epitope mapping by indirect immunofluorescence. The 4H9, 3F2, and C10 antibodies all recognized the C-terminal 72–149 amino acid region of NSP7α. 4H9 reacted with amino acids 135–143, but 3F2 and C10 did not react with any truncated polypeptide. In addition, by using the monoclonal antibodies, NSP7α was localized solely in the cytoplasm, while the N protein was distributed in the cytoplasm and nucleus. The collective findings of the antigenicity and epitope of NSP7α will be helpful for understanding the antigenicity of NSP7α and developing PRRSV diagnostic methods. •Three strains mAbs specific against PRRSV-2 NSP7α were produced.•The aa 135–143 of PRRSV NSP7α was identified as highly conserved linear epitopes among PRRSV-2.•NSP7α could induce high level antibody in piglet serum at 14 d post PRRSV infection.