针对狂犬病病毒P蛋白的单克隆抗体开发及表位表征研究

Abstract

Rabies is a fatal zoonotic disease caused by rabies virus (RABV), resulting in approximately 59,000 deaths annually worldwide and posing a serious threat to public health. The RABV phosphoprotein (P protein) plays crucial roles in viral replication, transcription, and immune antagonism; however, its immunogenic properties have not been fully characterized. In this study, the RABV P protein was expressed in an Escherichia coli expression system and used to immunize mice, resulting in the generation of six P protein-specific monoclonal antibodies (mAbs). Using an overlapping peptide-based truncation strategy, two linear B-cell epitopes were identified: 52 DMKRLHLDDEKSSNL 66 and 177 VAPGPPALEWSATNE 191 . Alanine-scanning mutagenesis revealed that residues D52, M53, R55, L56, and L58 were critical for the recognition of epitope 52 DMKRLHLDDEKSSNL 66 by mAbs 2D2 and 18G7. Residues G180, P181, and W186 were essential for recognition of epitope 177 VAPGPPALEWSATNE 191 by mAbs 3D7, 15D8, 16D3, and 16C6. Notably, although some amino acid residues within epitopes P1-5 and P4-2 exhibited high variability among representative RABV strains, the critical residues recognized by these monoclonal antibodies were highly conserved. These findings provide new insights into the antigenic structure of the RABV P protein and may contribute to future studies on its functional characterization, as well as the development of P protein-based diagnostic reagents and subunit vaccines.