A rationally designed inactivatedSalmonellaTyphimurium vaccine induces strong and long-lasting immune responses in pigs

Abstract

AbstractSalmonella entericasubspeciesentericaserovar Typhimurium (S.Tm) poses a considerable threat to public health due to its zoonotic potential. Human infections are mostly foodborne, and pork and pork products are ranked among the top culprits for transmission. In addition, the high percentage of antibiotic resistance, especially in monophasicS.Tm, limits treatment options when needed. BetterS.Tm control would therefore be of benefit both for farm animals and for safety of the human food chain.A promising pre-harvest intervention is vaccination. In this study we tested safety and immunogenicity of an oral inactivatedS.Tm vaccine, which has been recently shown to generate an “evolutionary trap” and to massively reduceS.Tm colonization and transmission in mice. We show that this vaccine is highly immunogenic and safe in post-weaning pigs and that administration of a single oral dose results in a strong and long-lasting serum IgG response. This has several advantages over existing – mainly live – vaccines againstS.Tm, both in improved seroconversion and reduced risk of vaccine-strain persistence and reversion to virulence.