Induces Protection and Enhances Innate Immunity of Chickens, and Other Poultry Against Pathogen-Caused Diseases
This in ovo vaccination uses genetically modified Salmonella vectored vaccines to induce protection of chickens and other poultry types against bacterial, viral, and parasite pathogens. The global demand for poultry products has increased significantly, making poultry meat and eggs the most consumed sources of protein worldwide. The United States alone produced approximately 46.2 billion pounds of chicken meat and 109.5 billion eggs in 2022, generating a revenue of $69 billion. The global demand for affordable, healthy, and nutritious poultry products has driven intensive production systems with high bird density and rapid growth rates. These conditions have contributed to the rise of antibiotic-resistant bacteria, increasing poultry’s susceptibility to infection and facilitating the spread of pathogens such as Salmonella, Clostridium perfringens, Campylobacter jejuni, avian pathogenic Escherichia coli (APEC), Eimeria species, avian influenza, and other respiratory viruses. Many of these also pose significant foodborne and zoonotic risks for humans. For example, Salmonella app. is a major concern in the poultry industry, accounting for nearly 35% of hospitalizations and 28% of mortality related to foodborne illnesses in the United States.
Current control measures rely heavily on post-hatch vaccination, biosecurity practices, and historical use of antimicrobial growth promoters. This contributes to the emergence of drug-resistant bacteria, provides incomplete or serotype-limited protection, often fails to protect birds in the first days of life, and can be labor-intensive and costly to deploy at scale. Therefore, there is an evident need for an innovative method to induce protection of chickens against diseases caused by pathogens and to lower rates of contaminated poultry-derived food products and the incidence of human foodborne illnesses.
Researchers at the University of Florida have developed a self-destructing, genetically modified Salmonella vectored vaccine platform for in ovo administration at 18 days of incubation. They are designed to induce robust innate and acquired immune responses before hatch and reduce early colonization by major bacterial, viral, and parasitic pathogens. By providing a safe and effective way to immunize chickens, this vaccine has the potential to lower rates of contaminated food products and human foodborne illnesses, ultimately benefiting both the poultry industry and the public health.
Application
Safe, biologically contained in ovo vaccination of 18-day-old chicken embryos using self-destructing Salmonella vectored vaccines to confer early, broad protection against major poultry pathogens
Advantages
- Stimulates strong innate and acquired immune responses, including cross-protective immunity against multiple enteric pathogens, enhancing overall health
- Provides early protection against infection and intestinal colonization, immediately addressing a high-risk window
- Supports healthy development of newly hatched birds ensuring they achieve their genetic potential
- Prevents colonization by pathogens of public health importance, lowering rates of contaminated poultry-derived products and rates of human foodborne illnesses
- Enables scalable, automated in ovo delivery compatible with existing commercial hatchery equipment, decreasing labor, time, and cost versus post-hatch vaccination programs
Technology
This platform for in ovo vaccination with genetically modified Salmonella vectored vaccines induces protection against various diseases caused by infectious pathogens. The vaccine comprises a suite of genetically engineered self-destructing Salmonella enterica based vaccine vectors, termed self-destructing Protective Immunity Enhanced Salmonella Vaccine (sd-PIESV) strains, and self-destructing attenuated adjuvant Salmonella (SDAAS) strains that are administered at about day 18 of chicken embryo development.
Vaccine plasmids such as pG8R110, pG8R111, and pG8R114 provide arabinose-regulated murA and/or asdA expression to maintain a balanced-lethal relationship and impose regulated delayed lysis, while carrying codon-optimized genes encoding protective antigens from Clostridium perfringens, Campylobacter jejuni, Eimeria maxima and E. tenella, and influenza virus. Secretion modules based on enhanced type 2 secretion systems promote antigen release and outer membrane vesicle formation, and type3 secretion modules enable delivery of conserved T-cell epitopes to the host cell cytosol.
This mechanism prevents strain persistence in the environment and reduces the prevalence of antibiotic resistance. The platform combines the safety of a self-destructing mechanism with the efficacy of a live attenuated vaccine. Key technical features include the use of a regulated delayed lysis system, which allows for controlled release of antigens, and the incorporation of multiple antigens, which provides broad protection against various diseases.
Brochure
