A M. bovis-BoHV-1 Combined Vaccine Confers Protection Against Diverse Bovine
Herpesvirus Type 1 Strains

Mycoplasma bovis (M. bovis) and bovine herpesvirus 1 (BoHV-1) are two major infections that seriously impair cattle's reproductive and respiratory systems. We created an M. bovis-BoHV-1 combined vaccine and assessed its safety and effectiveness in our earlier work. This study evaluated a novel combined vaccine comprising attenuated M. bovis and marker BoHV-1 antigens for its immunogenicity and efficacy in protecting cattle against diverse BoHV-1 genotypes. The cattle were divided into four groups: M. bovis-BoHV-1 combined vaccine, inactivated vaccine, non-immune challenge and blank control groups. The results demonstrated that the combined vaccine group prompted a high degree of production of cytokines, B cells, and T cell-associated signaling pathways, and was able to elicit considerably greater antibody titers (p < 0.01). Subsequently, RT-PCR was used to assess viral shedding after the groups were challenged with either the BoHV-1 1.1a or 1.2b strains. Under experimental challenge conditions, the combined vaccine reduced BoHV-1 viral shedding by 70% in vaccinated cattle compared to controls, and a shorter duration of virus shedding was also observed in the vaccinated groups compared to the non-immune challenge group for different BoHV-1 strain challenges, with about 6-8 day earlier clearance of virus shedding compared to the non-immune challenge group. Notably, the combined vaccine provided cross-protection against multiple BoHV-1 genotypes, demonstrating its potential as a broad-spectrum solution for controlling bovine respiratory disease. These findings provide important insights into effective disease control strategies for cattle herds.