Immunization with recombinant E^rns-LTB fusion protein elicits protective immune responses against bovine viral diarrhea virus

Bovine viral diarrhea virus (BVDV), a major infectious pathogen and is associated with major economic losses and significant impact on animal welfare worldwide. Here, recombinant E-rns -LTB protein vaccine containing MF59 adjuvant was prepared and assessed using a mouse model. The recombinant plasmid (pET32a-E-rns-LTB) was constructed and transformed into BL21 (DE3) cells to produce E-rns-LTB protein. The E-rns-LTB protein was formulated with MF59 adjuvant, when delivered intraperitoneally in mice, exhibited higher immunogenic and induced superior levels of anti-BVDV IgG compared with the MF59 adjuvanted E-rns protein. Importantly, after challenged with different BVDV BJ175170 and BJ1305 isolate strains, mice inoculated with E-rns -LTB protein displayed alleviated pathological damage and decreased plasma virus shedding compared with mice inoculated with E-rns protein. The enhanced protection from E-rns -LTB protein is mediated by T cell immunity and primarily based on CD4(+) T helper (Th) and CD8(+) cytotoxic T lymphocyte (CTL), these results suggest that E-rns -LTB protein has potential to protect against a broad range of BVDV strains thereby providing a novel direction for developing broadly protective vaccines.