Abstract
PURPOSE: Salmonellosis in poultry is a serious economic burden. A major concern is the public health hazard caused by consumption of Salmonella-contaminated poultry products. Currently used Salmonella vaccines are ineffective in combating poultry Salmonellosis warranting the need of a potent vaccine, especially an oral vaccine that can elicit robust local intestinal immunity. MATERIALS AND METHODS: A Salmonella subunit chitosan nanoparticles (NPs)-based vaccine was prepared that contained immunogenic outer membrane proteins (OMPs) and -flagellin (F) protein (OMPs-F-CS NPs). OMPs-F-CS NPs were administered as an oral vaccine in layer chickens and the resultant humoral and cell-mediated immune responses and localization of NPs were examined using standard detection methods. RESULTS: We demonstrated targeting of surface F-protein coated chitosan NPs to immune cells when delivered orally to layer chickens, the particles were localized in ileal Peyer's patches. The OMPs-F-CS NPs vaccinated layer chickens had significantly higher OMPs-specific mucosal IgA production and lymphocyte proliferation response. The candidate vaccine increased the expression of toll-like receptor (TLR)-2, TLR-4, IFN-γ, TGF-ß and IL-4 mRNA expression in chicken cecal tonsils. CONCLUSION: Our study demonstrated that the chitosan-based oral Salmonella nanovaccine targets immune cells of chickens and induced antigen-specific B and T cell responses. This candidate oral Salmonella nanovaccine has the potential to mitigate Salmonellosis in poultry.