Immune Response to Salmonella Enteritidis Infection in Broilers Immunized Orally With Chitosan-Based Salmonella Subunit Nanoparticle Vaccine

Chitosan-nanoparticle-based oral Salmonella enteritidis subunit vaccine elicits cross-protection against Salmonella typhimurium in broilers

Non-typhoidal Salmonella infection is a significant health and economic burden in poultry industry. Developing an oral vaccine to induce robust mucosal immunity in the intestines of birds, especially cross protection against different Salmonella serotypes is challenging. Therefore, a potent oral vaccine platform that can mitigate different serotypes of Salmonella is warranted for the poultry industry. We reported earlier that the Salmonella enteritidis (SE) immunogenic outer membrane proteins (OMPs) and flagellin (FLA) entrapped in mannose chitosan nanoparticles (OMPs-FLA-mCS NPs) administered prime-boost (d-3 and 3-wk later) by oral inoculation elicits mucosal immunity and reduces challenge SE colonization by over 1 log10 CFU in birds. In this study, we sought to evaluate whether the SE antigens containing OMPs-FLA-mCS NPs vaccine induces cross-protection against Salmonella typhimurium (ST) in broilers. Our data indicated that the OMPs-FLA-mCS NPs vaccine induced higher cross-protective antibody responses compared to commercial Poulvac ST vaccine (contains a modified-live ST bacterium). Particularly, OMPs-FLA-mCS-NP vaccine elicited OMPs and FLA antigens specific increased production of secretory IgA and IgY antibodies in samples collected at both post-vaccination and post-challenge timepoints compared to commercial vaccine group. Notably, the vaccine reduced the challenge ST bacterial load by 0.8 log10 CFU in the cecal content, which was comparable to the outcome of Poulvac ST vaccination. In conclusion, our data suggested that orally administered OMPs-FLA-mCS-NP SE vaccine elicited cross protective mucosal immune responses against ST colonization in broilers. Thus, this candidate vaccine could be a viable option replacing the existing both live and killed Salmonella vaccines for birds.

Current status of nano-vaccinology in veterinary medicine science

Vaccination programmes provide a safe, effective and cost-efficient strategy for maintaining population health. In veterinary medicine, vaccination not only reduces disease within animal populations but also serves to enhance public health by targeting zoonoses. Nevertheless, for many pathogens, an effective vaccine remains elusive. Recently, nanovaccines have proved to be successful for various infectious and non-infectious diseases of animals. These novel technologies, such as virus-like particles, self-assembling proteins, polymeric nanoparticles, liposomes and virosomes, offer great potential for solving many of the vaccine production challenges. Their benefits include low immunotoxicity, antigen stability, enhanced immunogenicity, flexibility sustained release and the ability to evoke both humoral and cellular immune responses. Nanovaccines are more efficient than traditional vaccines due to ease of control and plasticity in their physio-chemical properties. They use a highly targeted immunological approach which can provide strong and long-lasting immunity. This article reviews the currently available nanovaccine technology and considers its utility for both infectious diseases and non-infectious diseases such as auto-immunity and cancer. Future research opportunities and application challenges from bench to clinical usage are also discussed.

Identification of SNPs Related to Salmonella Resistance in Chickens Using RNA-Seq and Integrated Bioinformatics Approach

Potential single nucleotide polymorphisms (SNPs) were detected between two chicken breeds (Kashmir favorella and broiler) using deep RNA sequencing. This was carried out to comprehend the coding area alterations, which cause variances in the immunological response to Salmonella infection. In the present study, we identified high impact SNPs from both chicken breeds in order to delineate different pathways that mediate disease resistant/susceptibility traits. Samples (liver and spleen) were collected from Salmonella resistant (K. favorella) and susceptible (broiler) chicken breeds. Salmonella resistance and susceptibility were checked by different pathological parameters post infection. To explore possible polymorphisms in genes linked with disease resistance, SNP identification analysis was performed utilizing RNA seq data from nine K. favorella and ten broiler chickens. A total of 1778 (1070 SNPs and 708 INDELs) and 1459 (859 SNPs and 600 INDELs) were found to be specific to K. favorella and broiler, respectively. Based on our results, we conclude that in broiler chickens the enriched pathways mostly included metabolic pathways like fatty acid metabolism, carbon metabolism and amino acid metabolism (Arginine and proline metabolism), while as in K. favorella genes with high impact SNPs were enriched in most of the immune-related pathways like MAPK signaling pathway, Wnt signaling pathway, NOD-like receptor signaling pathway, etc., which could be a possible resistance mechanism against salmonella infection. In K. favorella, protein-protein interaction analysis also shows some important hub nodes, which are important in providing defense against different infectious diseases. Phylogenomic analysis revealed that indigenous poultry breeds (resistant) are clearly separated from commercial breeds (susceptible). These findings will offer fresh perspectives on the genetic diversity in chicken breeds and will aid in the genomic selection of poultry birds.

Immunological evaluation of a recombinant vaccine delivered with an analogous hyaluronic acid chitosan nanoparticle-hydrogel against Toxoplasma gondii in mice

BACKGROUND

Toxoplasma gondii (T. gondii) is not only a threat to the public health but it also poses adverse impacts on the livestock industry. This study aimed to develop a recombinant vaccine composed of T. gondii microneme protein 6 (TgMIC6) and T. gondii rhoptry protein 18 (TgROP18).The vaccine was delivered with a novel vector, named analogous hyaluronic acid chitosan nanoparticle-hydrogel (AHACNP-HG) and its immune protection was evaluated.

METHODS

The recombinant MIC6 and ROP18 proteins were obtained by affinity chromatography and loaded onto AHACNP-HG by magnetic stirring. The characterizations of AHACNP-HG were investigated, including its structure, rheological property, nanoparticle size and zeta potential, its ability to release protein in vitro and toxicology in vivo. The immunological and anti-infection effects of AHACNP-HG/rMIC6/rROP18 were examined in the mice model.

RESULTS

AHACNP-HG presented a characteristic of composite system and possessed biosecurity with excellent protein control-release property. AHACNP-HG/rMIC6/rROP18 vaccine enhanced a mixed Th1/Th2 cellular immune response accompanied by an increased level of the cytokines, IFN-γ and IL-10. It also provoked a stronger humoral immune response. Additionally, after challenge with T. gondii tachyzoite, AHACNP-HG/rMIC6/rROP18 inoculation prolonged the survival time of mice.

CONCLUSION

Our data indicated that mixed rMIC6 and rROP18 induced strong immune response and played a certain protective role in controlling T. gondii infection, and the novel adjuvant AHACNP-HG improved modestly some immunogenicity properties in mouse model, which indicated that it can be used as a novel delivery system in vaccine development.

Chitosan: a promising natural polysaccharide feed additive in poultry production systems

In recent years, the hazardous use of antibiotic growth promotors in the poultry industry has led to the development of drug resistance and violative tissue residues. Therefore, the European Union Regulation banned application of these growth promotors, and the international authorities have searched for other natural and safe feed additive sources as substitutes for antibiotics. Chitosan has been used as a feed-additive alternative in veterinary medicine practices worldwide. Chitosan and chitosan-based nanoparticles have been extensively investigated in the poultry production system and have proved several positive impacts. The overall performance parameters of broilers and layers have been improved following dietary treatments with chitosan. Besides, chitosan showed antimicrobial activity against many bacterial, fungal, viral, and parasitic diseases as well as boosting of the immune response. Modulation of the antioxidant activity and modification of some blood parameters have also been detected owing to dietary chitosan supplementations. Moreover, chitosan nanoparticles have been now applied as a vaccine delivery vehicle and a mucosal adjuvant for many important poultry bacterial and viral diseases. Therefore, this review article sheds light on the effects of chitosan and its nanoparticle forms on the production traits of broilers and layers, their antimicrobial, immuno-regulatory, and antioxidant properties, as well as their effects on the blood constituents and vaccine production.

Vaccinating Meat Chickens against Campylobacter and Salmonella: A Systematic Review and Meta-Analysis

Foodborne enteritis is a major disease burden globally. Two of the most common causative bacterial enteropathogens in humans are Campylobacter and Salmonella species which are strongly associated with the consumption of raw or contaminated chicken. The poultry industry has approached this issue by use of a multi-hurdle method across the production chain to reduce or eliminate this risk. The use of poultry vaccines is one of these control methods. A systematic review and meta-analysis of vaccination effects against caecal Campylobacter and Salmonella were performed on primary research published between 2009 and 2022. Screening was conducted by three reviewers with one reviewer performing subsequent data extraction and one reviewer performing the risk of bias assessment. The confidence in cumulative evidence was evaluated based on the GRADE method. Meta-analyses were performed using standardised mean differences (SMDs) with additional analyses and random effects regression models on intervention effects grouped by the vaccine type. A total of 13 Campylobacter and 19 Salmonella studies satisfied the eligibility criteria for this review. Many studies included multi-arm interventions, resulting in a total of 25 Campylobacter and 34 Salmonella comparators which were synthesised. The analyses revealed a large reduction in pathogen levels; however, many effects required statistical adjustment due to unit of analysis errors. There was a moderate level of confidence in the reduction of Campylobacter by 0.93 SMD units (95% CI: −1.275 to −0.585; p value < 0.001) and a very low level of confidence in the reduction of Salmonella by 1.10 SMD units (95% CI: −1.419 to −0.776; p value < 0.001). The Chi2 test for heterogeneity (p value 0.001 and <0.001 for Campylobacter and Salmonella, respectively) and the I2 statistic (52.4% and 77.5% for Campylobacter and Salmonella, respectively) indicated high levels of heterogeneity in the SMDs across the comparators. The certainty of gathered evidence was also affected by a high risk of study bias mostly due to a lack of detailed reporting and, additionally for Salmonella, the presence of publication bias. Further research is recommended to source areas of heterogeneity, and a conscious effort to follow reporting guidelines and consider units of analysis can improve the strength of evidence gathered to provide recommendations to the industry.

Chitosan-Based Nanomaterial as Immune Adjuvant and Delivery Carrier for Vaccines

With the support of modern biotechnology, vaccine technology continues to iterate. The safety and efficacy of vaccines are some of the most important areas of development in the field. As a natural substance, chitosan is widely used in numerous fields-such as immune stimulation, drug delivery, wound healing, and antibacterial procedures-due to its good biocompatibility, low toxicity, biodegradability, and adhesion. Chitosan-based nanoparticles (NPs) have attracted extensive attention with respect to vaccine adjuvants and delivery systems due to their excellent properties, which can effectively enhance immune responses. Here, we list the classifications and mechanisms of action of vaccine adjuvants. At the same time, the preparation methods of chitosan, its NPs, and their mechanism of action in the delivery system are introduced. The extensive applications of chitosan and its NPs in protein vaccines and nucleic acid vaccines are also introduced. This paper reviewed the latest research progress of chitosan-based NPs in vaccine adjuvant and drug delivery systems.

The Influence of Nanoparticle on Vaccine Responses against Bacterial Infection

Nowadays, nanovaccine is considered as an evolving method in the field of vaccination to induce immunity in the human body against various diseases, including bacterial or viral diseases as well as virulent tumors. Nanovaccines are more efficient than traditional vaccines since they could potentially induce both humoral and cellular immune reactions. Various studies have shown that nanoparticles with multiple compounds have been designed as delivery systems or as adjuvants for vaccines. Nanoparticles could function as a drug delivery tool, as an adjuvant to promote antigen processing, and as an immune modulator to induce immune responses. These nanoparticles generate immune responses through activating immune cells as well as through the production of antibody responses. Design engineering of nanoparticles (NPs) used to produce nanovaccines to induce immunity in the human body needs comprehensive information about the ways they interact with the component of immune system. Challenges remain due to the lack of sufficient and comprehensive information about the nanoparticles' mode of action. Several studies have described the interactions between various classes of nanoparticles and the immune system in the field of prevention of bacterial infections. The results of some studies conducted in recent years on the interaction between nanoparticles and biosystems have considerably affected the methods used to design nanoparticles for medical applications. In this review, NPs’ characteristics influencing their interplay with the immune system were discussed in vivo. The information obtained could lead to the development of strategies for rationalizing the design of nanovaccines in order to achieve optimum induction of immune response.

Immunization of Broiler Chickens With a Killed Chitosan Nanoparticle Salmonella Vaccine Decreases Salmonella Enterica Serovar Enteritidis Load

There is a critical need for an oral-killed Salmonella vaccine for broilers. Chitosan nanoparticle (CNP) vaccines can be used to deliver Salmonella antigens orally. We investigated the efficacy of a killed Salmonella CNP vaccine on broilers. CNP vaccine was synthesized using Salmonella enterica serovar Enteritidis (S. Enteritidis) outer membrane and flagella proteins. CNP was stable at acidic conditions by releasing 14% of proteins at pH 5.5. At 17 h post-incubation, the cumulative protein release for CNP was 75% at pH 7.4. Two hundred microliters of PBS with chicken red blood cells incubated with 20 μg/ml CNP released 0% hemoglobin. Three hundred chicks were allocated into 1) Control, 2) Challenge, 3) Vaccine + Challenge. At d1 of age, chicks were spray-vaccinated with PBS or 40 mg CNP. At d7 of age, chicks were orally-vaccinated with PBS or 20 μg CNP/bird. At d14 of age, birds were orally-challenged with PBS or 1 × 107 CFU/bird of S. Enteritidis. The CNP-vaccinated birds had higher antigen-specific IgY/IgA and lymphocyte-proliferation against flagellin (p &lt; 0.05). At 14 days post-infection, CNP-vaccinated birds reversed the loss in gut permeability by 13% (p &lt; 0.05). At 21 days post-infection, the CNP-vaccinated birds decreased S. Enteritidis in the ceca and spleen by 2 Log10 CFU/g, and in the small intestine by 0.6 Log10 CFU/g (p &lt; 0.05). We conclude that the CNP vaccine is a viable alternative to conventional Salmonella poultry vaccines.

A Novel Approach against Salmonella: A Review of Polymeric Nanoparticle Vaccines for Broilers and Layers

This work discusses the present-day limitations of current commercial Salmonella vaccines for broilers and layers and explores a novel approach towards poultry vaccination using biodegradable nanoparticle vaccines against Salmonella. With the increasing global population and poultry production and consumption, Salmonella is a potential health risk for humans. The oral administration of killed or inactivated vaccines would provide a better alternative to the currently commercially available Salmonella vaccines for poultry. However, there are currently no commercial oral killed-vaccines against Salmonella for use in broilers or layers. There is a need for novel and effective interventions in the poultry industry. Polymeric nanoparticles could give way to an effective mass-administered mucosal vaccination method for Salmonella. The scope of this work is limited to polymeric nanoparticles against Salmonella for use in broilers and layers. This review is based on the information available at the time of the investigation.

Nanovaccines against Animal Pathogens: The Latest Findings

Nowadays, safe and efficacious vaccines represent powerful and cost-effective tools for global health and economic growth. In the veterinary field, these are undoubtedly key tools for improving productivity and fighting zoonoses. However, cases of persistent infections, rapidly evolving pathogens having high variability or emerging/re-emerging pathogens for which no effective vaccines have been developed point out the continuing need for new vaccine alternatives to control outbreaks. Most licensed vaccines have been successfully used for many years now; however, they have intrinsic limitations, such as variable efficacy, adverse effects, and some shortcomings. More effective adjuvants and novel delivery systems may foster real vaccine effectiveness and timely implementation. Emerging vaccine technologies involving nanoparticles such as self-assembling proteins, virus-like particles, liposomes, virosomes, and polymeric nanoparticles offer novel, safe, and high-potential approaches to address many vaccine development-related challenges. Nanotechnology is accelerating the evolution of vaccines because nanomaterials having encapsulation ability and very advantageous properties due to their size and surface area serve as effective vehicles for antigen delivery and immunostimulatory agents. This review discusses the requirements for an effective, broad-coverage-elicited immune response, the main nanoplatforms for producing it, and the latest nanovaccine applications for fighting animal pathogens.

Immunity and Protective Efficacy of Mannose Conjugated Chitosan-Based Influenza Nanovaccine in Maternal Antibody Positive Pigs

Parenteral administration of killed/inactivated swine influenza A virus (SwIAV) vaccine in weaned piglets provides variable levels of immunity due to the presence of preexisting virus specific maternal derived antibodies (MDA). To overcome the effect of MDA on SwIAV vaccine in piglets, we developed an intranasal deliverable killed SwIAV antigen (KAg) encapsulated chitosan nanoparticles called chitosan-based NPs encapsulating KAg (CS NPs-KAg) vaccine. Further, to target the candidate vaccine to dendritic cells and macrophages which express mannose receptor, we conjugated mannose to chitosan (mCS) and formulated KAg encapsulated mCS nanoparticles called mannosylated chitosan-based NPs encapsulating KAg (mCS NPs-KAg) vaccine. In MDA-positive piglets, prime-boost intranasal inoculation of mCS NPs-KAg vaccine elicited enhanced homologous (H1N2-OH10), heterologous (H1N1-OH7), and heterosubtypic (H3N2-OH4) influenza virus-specific secretory IgA (sIgA) antibody response in nasal passage compared to CS NPs-KAg vaccinates. In vaccinated upon challenged with a heterologous SwIAV H1N1, both mCS NPs-KAg and CS NPs-KAg vaccinates augmented H1N2-OH10, H1N1-OH7, and H3N2-OH4 virus-specific sIgA antibody responses in nasal swab, lung lysate, and bronchoalveolar lavage (BAL) fluid; and IgG antibody levels in lung lysate and BAL fluid samples. Whereas, the multivalent commercial inactivated SwIAV vaccine delivered intramuscularly increased serum IgG antibody response. In mCS NPs-KAg and CS NPs-KAg vaccinates increased H1N2-OH10 but not H1N1-OH7 and H3N2-OH4-specific serum hemagglutination inhibition titers were observed. Additionally, mCS NPs-KAg vaccine increased specific recall lymphocyte proliferation and cytokines IL-4, IL-10, and IFNγ gene expression compared to CS NPs-KAg and commercial SwIAV vaccinates in tracheobronchial lymph nodes. Consistent with the immune response both mCS NPs-KAg and CS NPs-KAg vaccinates cleared the challenge H1N1-OH7 virus load in upper and lower respiratory tract more efficiently when compared to commercial vaccine. The virus clearance was associated with reduced gross lung lesions. Overall, mCS NP-KAg vaccine intranasal immunization in MDA-positive pigs induced a robust cross-reactive immunity and offered protection against influenza virus.

Protection Conferred by Drinking Water Administration of a Nanoparticle-Based Vaccine against Salmonella Enteritidis in Hens

Salmonellosis remains a major medical and an unmet socioeconomic challenge. Worldwide, more than three million deaths per year are associated with Salmonella enterica serovar Enteritidis infections. Although commercially available vaccines for use in poultry exist, their efficacy is limited. We previously described a method for isolating a heat extract (HE) fraction of the cell surface of S. Enteritidis that contained major antigenic complexes immunogenic in hens naturally infected with the bacterium. One single dose of S. Enteritidis’ HE induced protection against lethal salmonellosis in mice. Furthermore, HE encapsulation in nanoparticles of the copolymer of methyl vinyl ether and maleic anhydride (PVM/MA), Gantrez AN, improved and prolonged the protection against the disease in mice. We formulated new preparations of Gantrez AN nanoparticles with HE S. Enteritidis and assessed their stability in drinking water and their efficacy in hens after experimental infection. The oral treatment of six-week-old hens with two doses of HE nanoparticles significantly reduced the Salmonella excretion in hens. Due to the effectiveness of the treatment in reducing bacterial excretion, we conclude that HE nanoencapsulation obtained from S. Enteritidis is a viable novel vaccination approach against salmonellosis in farms.

Chitosan Nanoparticle Based Mucosal Vaccines Delivered Against Infectious Diseases of Poultry and Pigs

Infectious disease of poultry and pig are major threat to health and cause severe economic loss to the food industry and a global food safety issue. Poultry and pig act as a mixing vessel of zoonotic transmission of disease to humans. Effective mucosal vaccines used in animals could reduce the impact of diseases in food animals. Chitosan is a biocompatible polymer, and its positive charge makes it a natural mucoadhesive agent. Therefore, since last one-decade chitosan derived nanoparticles (CS NPs) have been in use widely to deliver vaccine antigens in animals through mucosal route. Primary route of entry of most infectious disease pathogen is through oral and nasal routes, and the CS NPs based vaccines delivered through that routes enhance the immunogenicity of encapsulated vaccine antigens by targeting the cargo to mucosal microfold cells, dendritic cells and macrophages. Resulting in induction of robust secretory and systemic antibodies and/or cell mediated immune response which provides protection against infections. To date, CS NPs is being widely used for mucosal vaccine delivery in poultry and pigs to control bacterial and viral infections, and tested in several preclinical trials for vaccine delivery in humans. In this review, we highlighted the progress so far made in using CS NPs as a vehicle for mucosal vaccine delivery against infectious and zoonotic diseases of poultry and pigs. Discussed about the need of CS NPs modifications, CS NPs based vaccines induced immune responses and its role in protection, and challenges in vaccination and future directions.

Mannose-Modified Chitosan-Nanoparticle-Based Salmonella Subunit OralVaccine-Induced Immune Response and Efficacy in a Challenge Trial in Broilers

Controlling Salmonella enterica serovar Enteritidis (SE) infection in broilers is a huge challenge. In this study, our objective was to improve the efficacy of a chitosan nanoparticle (CS)-based Salmonella subunit vaccine for SE, containing immunogenic outer membrane proteins (OMP) and flagellin (FLA), called the CS(OMP+FLA) vaccine, by surface conjugating it with mannose to target dendritic cells, and comparing the immune responses and efficacy with a commercial live Salmonella vaccine in broilers. The CS(OMP+FLA)-based vaccines were administered orally at age 3 days and as a booster dose after three weeks, and the broilers were challenged with SE at 5 weeks of age. Birds were sacrificed 10 days post-challenge and it was observed that CS(OMP+FLA) vaccine surface conjugated with both mannose and FLA produced the greatest SE reduction, by over 1 log₁₀ colony forming unit per gram of the cecal content, which was comparable to a commercial live vaccine. Immunologically, specific mucosal antibody responses were enhanced by FLA-surface-coated CS(OMP+FLA) vaccine, and mannose-bound CS(OMP+FLA) improved the cellular immune response. In addition, increased mRNA expression of Toll-like receptors and cytokine was observed in CS(OMP+FLA)-based-vaccinated birds. The commercial live vaccine failed to induce any such substantial immune response, except that they had a slightly improved T helper cell frequency. Our data suggest that FLA-coated and mannose-modified CS(OMP+FLA) vaccine induced robust innate and adaptive cell-mediated immune responses and substantially reduced the Salmonella load in the intestines of broilers.