Identification of novel B-cell epitopes on the capsid protein of type 1 porcine astrovirus, using monoclonal antibodies

• Published in: International journal of biological macromolecules 2021-10, Vol.189, p.939-947
• Main Authors: Zhang, Wenchao, Wang, Weiyi, Liu, Xin, Chen, Ying, Ouyang, Kang, Wei, Zuzhang, Liu, Huan, Huang, Weijian
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Antibodies, Monoclonal - metabolism; B-cell epitope; B-lymphocytes; blood serum; Capsid protein; Capsid Proteins - chemistry; Capsid Proteins - immunology; coat proteins; cross reaction; Cross Reactions - immunology; diarrhea; encephalitis; epitopes; Epitopes, B-Lymphocyte - immunology; Female; Mamastrovirus - immunology; Mamastrovirus 3; Mice; Mice, Inbred BALB C; Models, Molecular; Monoclonal antibodies; peptides; Peptides - chemical synthesis; Peptides - chemistry; Porcine astrovirus; sequence alignment; viruses
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2021.08.129

Porcine astrovirus (PAstV) is prevalent in pigs worldwide and could cause clinical symptoms such as diarrhea and encephalitis. The capsid protein (Cap) of PAstV plays a determinant role for virus immunological characteristics. In this study, the major antigenic regions of PAstV1 Cap were expressed through prokaryotic expression systems and immunized to BALB/c mice. Finally, two anti-Cap monoclonal antibodies (named mAb F4-4 and D3F10) were screened by indirect immune-fluorescence assay (IFA). A series of truncated GST-fused or artificially synthesized peptides were used to detect their reactivity with the mAbs and PAstV positive serum. Two novel B cell epitopes (120-GNNTFG-125, 485-RISDPTWFSA-494) were identified by using these two mAbs. Moreover, sequence alignment result showed that epitope 120-GNNTFG-125 was highly conserved in type 1 PAstV capsid protein. Cross-reactivity analysis further confirmed the genotype-specificity of mAb F4-4. The results of this study demonstrated to be the first description of monoclonal antibody preparation and B-cell epitope mapping on PAstV capsid protein, which may provide new information on the biological significance of PAstV capsid protein and lay a foundation for the development of PAstV immunological tests and genotype diagnostic methods. •Four monoclonal antibodies (mAbs) against PAstV1 were successfully developed.•Two mAbs could specifically react with the N terminal conserved and C terminal hypervariable region of PAstV Cap.•The B cell epitopes on PAstV Cap were further identified as 120GNNTFG125 and 485RISDPIWFSA494.•The epitope120GNNTFG125 was highly conserved and mAb F4-4 was PAtsV1 type-specific.