A Multi-Epitope Vaccine Design for Human Pasteurellosis using Outer Membrane β-barrel Proteins of Pasteurella multocida

Pasteurella multocida is a facultative anaerobic, Gram-negative coccobacillus that causes pasteurellosis in companion animals (cats and dogs), livestock, and poultry. Close contact with infected animals poses a significant zoonotic risk to humans through bite wounds, scratches, licking and transfer of bodily fluids. Current treatment relies mainly on antibiotics, and the lack of a licensed human vaccine further exacerbates the challenge. In the present study, a consensus-based computational approach was employed on the P. multocida Past 9 proteome. A total of 29 outer membrane β-barrel (OMBB) proteins, including TonB-dependent receptors, porins, autotransporters, adhesins and efflux pumps, were identified and used to design a multi-epitope vaccine (MEV) construct. B-cell and T-cell epitopes were predicted from the identified proteins. Ten epitopes each of cytotoxic T-lymphocyte (CTL) and helper T-lymphocyte (HTL), and three B-cell epitopes were selected based on their antigenicity, non-allergenicity, non-toxicity, surface accessibility, and conservation across eight P. multocida human-infecting strains. The MEV was supplemented with suitable adjuvants at the N-terminus to enhance its immunogenicity. The MEV construct, with a length of 459 amino acids, was predicted to be antigenic, non-allergenic, non-toxic and soluble upon expression. The MEV structural model was generated and subsequently validated, which indicated good structural quality. Molecular docking between MEV and human toll-like receptor 4 (TLR4) demonstrated strong binding affinity, and molecular dynamics simulation confirmed the structural stability of the MEV-TLR4 complex. Immune simulation of the MEV construct elicited a strong immune response. This study proposes a designed MEV candidate against human pasteurellosis and highlights OMBB proteins as potential immunogenic targets for vaccine development.