Chapter 20 - Practical Aspects of Poultry Vaccination
The immune system evolved to free multi-cellular organisms from invasive organisms that can cause disease. Similar to the mammalian immune system, that of chickens, the best studied among birds, is a multilayered network of cells and molecules and their interactions, which becomes active in a sequential form after the organisms invade the host and that play different roles. The chicken immune response, like that of mammals, can be divided into innate or non-specific and adaptive or specific, both of which are necessary for an effective vaccine-induced immunity as outlined in this chapter. Live-attenuated and killed vaccines are widely used in the control of infectious diseases of poultry. The practical application of poultry vaccination strategies and the use of vector vaccines are reviewed as well.
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H5 highly pathogenic avian influenza (HPAI) viruses of the Asian lineage (A/goose/Guangdong/1/96) belonging to clade 2.3.4.4 have spread worldwide through wild bird migration in two major waves: in 2014/2015 (clade 2.3.4.4c), and since 2016 up to now (clade 2.3.4.4b). Due to the increasing risk of these H5 HPAI viruses to establish and persist in the wild bird population, implementing vaccination in certain sensitive areas could be a complementary measure to the disease control strategies already applied.
In this study, the efficacy of a novel DNA vaccine, encoding a H5 gene (A/gyrfalcon/Washington/41088-6/2014 strain) of clade 2.3.4.4c was evaluated in specific pathogen-free (SPF) white leghorn chickens against a homologous and heterologous H5 HPAI viruses. A single vaccination at 2 weeks of age (1 dose), and a vaccination at 2 weeks of age, boosted at 4 weeks (2 doses), with or without adjuvant were characterized. The groups that received 1 dose with or without adjuvant as well as 2 doses with adjuvant demonstrated full clinical protection and a significant or complete reduction of viral shedding against homologous challenge at 6 and 25 weeks of age. The heterologous clade 2.3.4.4b challenge of 6-week-old chickens vaccinated with 2 doses with or without adjuvant showed similar results, indicating good cross-protection induced by the DNA vaccine. Long lasting humoral immunity was observed in vaccinated chickens up to 18 or 25 weeks of age, depending on the vaccination schedule. The analysis of viral transmission after homologous challenge showed that sentinels vaccinated with 2 doses with adjuvant were fully protected against mortality with no excretion detected. This study of H5 DNA vaccine efficacy confirmed the important role that this type of so-called third-generation vaccine could play in the fight against H5 HPAI viruses.
Immunogenicity and protective efficacy of an inactivated Newcastle disease virus vaccine encapsulated in poly-(lactic-co-glycolic acid) nanoparticles
2023, Poultry ScienceAn immunization experiment was conducted in specific pathogen-free chickens with the inactivated Newcastle disease virus (NDV) vaccine encapsulated in the poly-(lactic-co-glycolic) acid (PLGA) nanoparticles (NP) to evaluate its immunogenicity and protective efficacy. The NDV vaccine was prepared by inactivating one virulent Indian strain of NDV belonging to Genotype VII by using beta-propiolactone. PLGA nanoparticles encapsulating inactivated NDV were prepared by the solvent evaporation method. Scanning electron microscopy and zeta sizer analysis revealed that the (PLGA+NDV) NP were spherical, with an average size of 300 nm, having a zeta potential of -6 mV. The encapsulation efficiency and loading efficiency were 72% and 2.4%, respectively. On immunization trial in chicken, the (PLGA+NDV) NP induced significantly (P < 0.0001) higher levels of HI and IgY antibodies with the peak HI titer of 28 and higher expression of IL-4 mRNA. The consistency of higher antibody levels suggests slow and pulsatile release of the antigens from the (PLGA+NDV) NP. The nano-NDV vaccine also induced cell mediated immunity with higher expression of IFN-γ indicating strong Th1 mediated immune responses in contrast to the commercial oil adjuvanted inactivated NDV vaccine. Further, the (PLGA+NDV) NP afforded 100% protection against the virulent NDV challenge. Our results suggested that PLGA NP have adjuvant potential on induction of humoral as well as Th1 biased cell mediated immune responses and also enhanced protective efficacy of the inactivated NDV vaccine. This study provides an insight for development of PLGA NP based inactivated NDV vaccine using the same genotype circulating in the field as well as for other avian diseases at exigencies.
Biotechnology for Sustainable Production of Food
2023, Sustainable Food Science - A Comprehensive Approach: Volumes 1-4An overview is provided of the role of biotechnology in sustainably feeding the world's population. Sustainability is a holistic concept requiring food security without jeopardizing the environment and the biosphere. Sustainable production of food and feed crops is key to a sustainable society. Productive plant varieties that better withstand environmental stresses and pests, and can be grown with fewer inputs, will contribute to enhancing sustainability of life. Use of biofertilizers, biocontrol agents and crops better able to use nutrients, will lower the environmental impact of production. Productivity of animals will be enhanced and the environmental footprint of their production reduced through attention to biotechnology-based approaches to nutrition, healthcare and impact mitigation. Transgenic animals and plants are likely to have a role in sustainable production of food. Novel food sources, including cultured meats and microbial proteins are expected to replace at least partly some of the more traditional unsustainable animal-based protein sources. More productive and sustainable aquaculture will play an increasing role as a source of protein. Edible insects, consumed directly, or indirectly, will add to food supply. Efficiency and quality of food processing and preservation will be enhanced by the use of biotechnology-based methods, reducing spoilage and increasing availability for consumption.
Chitosan-based formulation of hemagglutinin antigens for oculo-nasal booster vaccination of chickens against influenza viruses
2022, Veterinary Immunology and ImmunopathologyCitation Excerpt :Due to disadvantages of needle-mediated immunization related to injecting individual birds by trained personnel, some alternative immunization techniques have been developed. For AIV control, in ovo vaccination is currently used to effectively deliver inactivated avian influenza oil-emulsion vaccines and vectored vaccines encoding H5 or H7 AIV HAs (Swayne et al., 2014; Schijns et al., 2014). Mass and/or easier vaccination can be provided by aerosol, spray, drinking water, or eye drop (Sharma, 1999), each of which acts via mucosa.
Avian influenza viruses (AIVs) and especially highly pathogenic (HP) AIVs of the H5 and H7 subtypes are of both veterinary and public health concern worldwide. In response to the demand for effective vaccines against H5N1 HPAIVs, we produced recombinant protein based on hemagglutinin (HA), a protective viral antigen. A fragment of the HA ectodomain, with a multibasic cleavage site deletion, was expressed in Escherichia coli, refolded, and chromatographically purified from inclusion bodies. Finally, the protein was formulated in Tris-HCl buffer of pH 8.0 or PBS of pH 7.4 to obtain antigens denoted rH5–1 and rH5–2, respectively. The systemic prime and boost immunizations proved that rH5–1 adsorbed to aluminum hydroxide induces anti-H5 HA neutralizing antibodies and protective immune responses against H5N1 HPAIVs in chickens. The present studies were aimed at stimulating immune responses via the mucosal routes using the systemic prime-mucosal boost strategy. Efficacy trials were performed in commercial layer chickens. For systemic and mucosal immunizations, H5 HA antigens were adjuvanted with aluminum hydroxide and chitosan glutamate, respectively. The first dose of rH5–2 was administered subcutaneously, while its second dose was administered subcutaneously, intraocularly, oculo-nasally, or intranasally. rH5–1 was delivered to the subcutaneously primed chickens by the intranasal route. Post-vaccination sera were analyzed for anti-H5 HA antibodies, using homologous ELISA and heterologous FluAC H5 and hemagglutination inhibition tests. Intraocularly and oculo-nasally delivered rH5–2 mixed with chitosan glutamate was capable of stimulating anti-H5 HA IgY antibody responses in the subcutaneously primed chickens; however, it was ineffective when administered by the intranasal route. Efficient intranasal boosting was achieved using rH5–1. The enhanced production of antigen-specific antibodies was reflected in the development of H5-subtype specific and hemagglutination inhibiting antibodies. Conclusively, the subcutaneous prime and oculo-nasal boost vaccination is proposed as the target strategy for future optimization.
Practical aspects of poultry vaccination
2021, Avian ImmunologyCommercial poultry is vaccinated routinely to protect the birds against infection or disease caused by several pathogens. The number of vaccines that are used in a particular flock depends on many factors such as disease pressure, pathogenicity of the pathogen, life span of the chicken, type of chicken, efficacy, availability, and costs of the vaccines, labor, regulations, efficacy of maternally derived antibodies, housing system, and relevance of vertical transmission. Vaccines can be applied individually or by mass application. Mass application by spray, feed, or drinking water is relatively cheap, fast, and safe regarding potential breaks of biosecurity as few people can vaccinate many birds in this way. Individual application is used for inactivated vaccines and for live vaccines that cannot, or cannot in a reliable way, be applied by a mucosal route.
Comparison of flagellin and an oil-emulsion adjuvant in inactivated Newcastle disease vaccine in stimulation of immunogenic parameters
2021, Comparative Immunology, Microbiology and Infectious DiseasesThe present study was designed to investigate the potential application of native (N) and recombinant (truncated modified [tmFliC] and full-length [flFliC]) flagellin proteins along with inactivated Newcastle disease virus (NDV). Fifty six SPF chickens were immunized twice with PBS (control), inactivated NDV (Ag), inactivated NDV/flFliC (AgF), inactivated NDV/tmFliC (AgT), inactivated NDV/N (AgN), commercial vaccine containing Montanide (Vac) and Vac/N (VacN), with a two-week interval. Blood was collected weekly and spleens were harvested after chickens were sacrificed. Interleukin-6 (IL-6) and tumor necrotic factor-α (TNF-α) gene expression in peripheral blood mononuclear cells were analyzed by Real-Time PCR. Antibody response was assessed by haemagglutination inhibition (HI). Cellular activity was quantified by MTT assay. Results showed that the most IL-6 and TNF-α gene expression was observed in AgF group (P < 0.01). The lowest gene expression among vaccinated groups was observed in Ag group for IL-6 and Ag and Vac group for TNF-α. The highest HI titer was observed in Vac, VacN, AgF and AgT groups. The AgF group showed the highest cellular activity (P < 0.01). In conclusion, flagellin-adjuvanted groups showed a pro-inflammatory effect and acted similarly to or better than the Vac group. Hence, flagellin can be proposed as a potential adjuvant for ND vaccine.