Salmonellosis in poultry is a serious economic burden. The major concern is the public health hazard by consumption of salmonella contaminated poultry meat and egg. Currently used salmonella vaccines are ineffective in combating the Salmonellosis of chicken thus warranting the need of a potent vaccine, especially an oral vaccine that can elicit robust local intestinal immunity. Biodegradable and biocompatible natural polymers are FDA approved vehicles for vaccine delivery. We prepared a candidate subunit chitosan nanoparticle vaccine containing the immunogenic outer membrane proteins (OMPs) and flagellar (F) protein of salmonella, and surface decorated with F-protein (OMPs-F-CS NPs). Physicochemical and biocompatibility properties of OMPs-F-CS NPs were studied in detail including its stability in stomach pH conditions. Salmonella targets the microfold (M) cells in the ileum Peyer’s patches (PPs) of chicken. We designed the oral OMPs-F-CS NPs vaccine to target ileal PPs to induce specific local intestinal immunity, and demonstrated that by ex vivo and in vivo studies. Layer chickens vaccinated orally with OMPs-F-CS NPs had significantly higher OMPs- specific intestinal mucosal antibody and OMPs-specific lymphocytes proliferation responses. Further, OMPs-F-CS NPs vaccination upregulated the expression of toll-like receptor (TLR) -2, TLR-4, IFN-g, IL-4 and GATA-3 mRNA levels in cecal tonsils of birds. In conclusion, we engineered chitosan based oral salmonella nanovaccine targeting intestinal PPs immune cells of birds, and demonstrated its ability to induce antigen specific mucosal antibody and T cell responses. Thus, our candidate oral salmonella vaccine has the potential to mitigate Salmonellosis in poultry.
Swine influenza A virus (SwIV) causes respiratory tract infection in pigs. Available SwIV vaccines fail to provide cross-protective immunity in pigs. Nano-11 is an amphiphilic nanoparticle (70–80nm) obtained from sweet corn-derived phytoglycogen. Nano-11 carries high surface positive charge and thus facilitates easy preparation of nanoparticle based vaccine by electrostatic interaction with killed SwIAV antigen (KAg) or peptides (negative charge). Earlier we showed that Nano-11 bound killed SwIV H1N2 Ag (Nano-11+KAg) delivered intranasally in pigs induced mucosal antibody response, but the challenge heterologous H1N1 SwIV load was not substantially reduced in the airways. In this study, KAg or conserved ten IAV peptides co-adsorbed with adjuvant Poly(I:C) (negative charge) on Nano-11 [Nano-11+KAg/peptides+Poly(I:C)] was vaccinated to influenza-free pigs intranasally, twice, and challenged with a heterologous SwIV. We observed increased SIgA and IgG responses in the airways and enhanced proliferation of IFN-g+ gd T cells in PBMCs in Nano-11+KAg+Poly(I:C) vaccinates compared to control. In Nano-11+peptides+Poly(I:C) vaccinates noticed an increased proliferation of IFN-g+ gd T cells and IFN-g+ cytotoxic T cells in PBMCs compared to control. Commercial vaccine group induced higher IgG response in serum and proliferation of IFN-g+ T-helper/memory cells in PBMCs compared to control. However, reduction in challenge virus load in any of the vaccinated groups was not statistically significant. In conclusion, inclusion of Poly(I:C) in Nano-11 flu vaccine improved the T cell response, but further improvements in the vaccine formulation is required to take advantage of this easy to prepare particle based mucosal flu vaccine.
Swine influenza virus (SwIV) causes considerable economic loss to pig industry, and some SwIV are zoonotic. This study was conducted to evaluate the cross-protective efficacy of PLGA (poly lactic-co-glycolic acid) nanoparticles (NPs) encapsulated SwIV vaccine in pigs. Killed SwIV H1N2 (δ lineage) antigens (KAg) were encapsulated in PLGA NPs of 200–300 nm (PLGA-KAg NPs), and influenza antibody-free pigs were prime-boost vaccinated intranasally as mist and challenged using a heterologous, virulent and zoonotic SwIV H1N1 (γ lineage). PLGA-KAg NPs induced maturation of pig macrophages and dendritic cells in vitro. In vaccinated pigs, PLGA-KAg NPs induced antigen specific lymphocyte proliferation and enhanced the frequency of T-helper/memory cells and cytotoxic T cells in peripheral blood mononuclear cells (PBMCs). In virus challenged pigs, the PLGA-KAg NPs vaccine rescued virus induced clinical fever, reduced the gross lung pathology, reduced the virus load in the lung sections with complete clearance of the virus from the lungs of most of the pigs; but the nasal virus shedding was not reduced. Immunologically, at post-challenge day 6 in a recall response in PBMCs of PLGA KAg NPs vaccinated pigs, a significant increase in IFN-γ secreting T cells against both vaccine and challenge viruses were detected. However, humoral immune response in those pigs was not augmented. In conclusion, intranasal delivery of PLGA NPs based SwIV induced cross-protective response through specific cell-mediated response. Future studies are aimed at boosting the mucosal antibody response.
Food processors aim to preserve as much as desirable quality attributes without compromising food safety. Thermal processing is the cheapest and most common method of food preservation across the world due to its outstanding record of assuring safety. The major challenge associated with the conventional heating method is to protect adequately desirable quality attributes like color, flavor, texture, nutrients and bioactive compounds to address the demands of modern health conscious consumers. One approach is to use kinetic models and adopt the principle of optimization. Reaction kinetic models can be used in process design to estimate quantitative impact on food components including microorganisms in foods. There are various types of linear and nonlinear kinetic models proposed by food engineers. However, the selection of appropriate process variables (time, temperature), knowledge on the product factors (e.g. pH, oBrix) and understanding their interactions with the model parameters (rate constant, activation energy) is important for accurately estimating the impact of the process. The purpose of this review is to summarize the principles and functions of thermal processing followed by the application of reaction kinetic models to estimate the impact of thermal process on the food components, namely microbial population, ascorbic acid, anthocyanin and furan in liquid foods and beverages. In addition, it illustrates how the model parameters can be used to optimize the process through time-temperature tolerance (TTT) curve. Furthermore, it explains the significance of high temperature short time process for selected food components.
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