Engineered OMVs of Salmonella displaying PlpE antigen provide effective protection against Pasteurella multocida infection in mice

Pasteurella multocida is a major zoonotic pathogen that contributes to progressive atrophic rhinitis and the porcine respiratory disease complex in pigs, leading to significant economic losses in the swine industry. Current vaccines show limited efficacy and safety concerns. Here, we developed an OMV-based antigen display system using the signal peptide of OmpD derived from Salmonella Typhimurium to present the protective antigen PlpE. The engineered OMVs enabled surface localization of PlpE and were evaluated via intranasal immunization in mice. Immunization induced strong antigen-specific IgA and IgG responses, along with a Th1/Th17-biased cellular response. The resulting serum exhibited complement-dependent bactericidal activity against P. multocida . Upon challenge with a 10× LD 50 dose, vaccinated mice showed significantly improved survival (80%) and reduced tissue damage. These findings demonstrate that engineered OMVs represent an effective antigen delivery platform for the control of porcine pasteurellosis.