Background/Objectives: Bovine ephemeral fever (BEF) is a significant disease affecting the cattle industry. The current control strategy for BEF in the field primarily relies on inactivated vaccines. However, some individuals have experienced hypersensitive reactions to these vaccines, prompting the exploration of subunit vaccines as a potential alternative for BEF prevention. Glycoprotein (G protein)-based subunit vaccines derived from virions have successfully induced neutralizing antibodies in cattle for over a decade. Nevertheless, the lack of recent studies evaluating their efficacy using recombinant proteins has raised concerns regarding the development of BEF subunit vaccines for practical field application. Therefore, the objective of this study was to evaluate the antigenicity of a novel truncated G protein produced in mammalian cells as a candidate subunit vaccine for BEF in cattle. Methods: In this study, the G protein with full ectodomain and a version truncated at the C-terminal domain were successfully generated using the ExpiCHO™ expression system. Vaccine efficacy was evaluated weekly by measuring neutralizing antibody titers and cytokine mRNA expression levels following vaccination. Results: Results show that the recombinant protein s510, derived from the G protein of BEF, can stimulate cattle to produce an average 35-fold increase in neutralizing antibodies after three doses of vaccination. The significant upregulation of IFN-γ mRNA supports the effectiveness of the s510-based subunit vaccine and indicates the activation of a cytotoxic immune response in cattle following vaccination. Conclusions: In conclusion, the results indicate that the recombinant protein s510 is a promising antigen for future BEF subunit vaccine development in this study.
Hsu et al. (Sun,) studied this question.