Engineering an Innovative Chimeric Multi-Epitope mRNA Based Vaccine Against Neonatal Calf Diarrhea Pathogens: Bovine Coronavirus, Bovine Rotavirus, and Escherichia coli K99

Neonatal calf diarrhea (NCD) is one of the most important problems of calf breeding across the world. It causes deaths in calves in the first 10 days of their life and it is mainly caused by E. coli, Bovine Rotavirus (BRV) and Bovine Coronavirus (BCoV). Ab-sence of an effective vaccine targeting the main causes of NCD makes disease control highly challenging. The current study aims to design multi-epitope mRNA based vac-cine targeting the major pathogens responsible for NCD using Immunoinformatic tools and molecular modelling approaches. BRV capsid protein VP6, BCoV Spike glycopro-tein and E. coli F5 fimbrial protein were used as antigenic proteins to predict potential epitopes. Fifteen selected epitopes were linked with suitable linkers and conjugated with build adjuvant, resulting in designing of stable, antigenic and non-allergenic vac-cine candidate against NCD pathogens. Furthermore, Molecular docking analysis shows strong binding affinity between the vaccine candidate and bovine Toll-like re-ceptors TLR2 and TLR4 at low energy and high stability. Based on these findings, the proposed multi-epitope vaccine represents a promising approach for prevention and control of neonatal calf diarrhea and provides a solid scientific foundation for future experimental studies to validate its efficacy and safety in vivo.