Recombinant bovine enterovirus based on a composite 2A protease cleavage site can serve as a live vaccine vector for antigen delivery

This study identifies an unreported strategy to enhance antigen expression in a BEV-based live vector by optimizing 2A protease cleavage site combinations. We demonstrate that specific 2A motifs derived from different enteroviruses significantly improve both recombinant BEV replication and foreign protein expression. Importantly, the engineered vector showed excellent in vivo safety and efficiently delivered antigen to multiple tissues. These findings establish a clear mechanistic and technical basis for improving picornavirus vector performance and highlight BEV as a promising platform for developing next-generation mucosal vaccines for animal disease control.