A multi-epitope subunit vaccine against Salmonella Enteritidis: design, immunogenicity, and protective efficacy in mice and chickens

Abstract

Salmonella enterica serovar Enteritidis (SE) not only causes systemic acute infections in chickens but can also be transmitted to humans through contaminated poultry and egg products, posing a serious threat to public health safety. In this study, we constructed a multi-epitope subunit vaccine against SE and investigated its immunostimulatory capacity and protective efficacy in mice and chickens. Ten B-cell epitopes and three T-cell epitopes were selected from two immunogenic proteins, FliC and SipD, and linked to construct a multi-epitope vaccine designated FLPD. In silico analysis revealed that FLPD exhibited favorable immunogenicity, stability, and immune-inducing potential. To validate its protective efficacy in vivo, immunization and challenge experiments were performed in mice and chickens. In mice, FLPD induced high IgG levels, with the 50 μg dose group showing particularly robust responses. After triple immunization, FLPD conferred 65% and 45% protection against lethal challenge with SE and Salmonella Typhimurium (ST), respectively. In chickens, triple immunization with FLPD and a commercial live attenuated vaccine achieved 70% and 80% protection against lethal SE challenge, respectively. Furthermore, FLPD-induced polyclonal antibodies showed cross-reactive effects against eight common Salmonella serovars in vitro. These findings suggest that FLPD is a promising vaccine candidate for combating SE infections.

Keywords

Salmonella Enteritidis / Salmonella Typhimurium / Multi-epitope vaccine

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Funding

the National Natural Science Foundation of China(No. 32072921)

RIGHTS & PERMISSIONS

The Author(s)