Georgia research project demonstrates safe, cost-effective mucosal immunization strategy against infectious laryngotracheitis virus.
December 3, 2024
The U.S. Poultry & Egg Association (USPOULTRY) and the USPOULTRY Foundation announced the completion of a funded research project by University of Georgia researchers demonstrating that a safe and cost-effective mucosal immunization strategy is possible using adjuvanted DNA plasmids expressing known immunogenic infectious laryngotracheitis virus (ILTV) glycoproteins delivered by calcium phosphate nanoparticles.
The research, made possible in part by an endowing USPOULTRY Foundation gift from Fieldale Farms Corp., is part of the association’s comprehensive research program encompassing all phases of poultry and egg production and processing. A summary of the project follows.
Project #738 – “DNA Immunization as a Safe & Economical Vaccination Strategy Against Infectious Laryngotracheitis Virus (ILTV) to Enhance Mucosal Protection in Primary Sites of Infection” – was led by Dr. Maricarmen Garcia, Poultry Diagnostic & Research Center at the University of Georgia’s College of Veterinary Medicine in Athens, Ga.
The study had three main objectives: (1) clone three ILTV glycoproteins into high-expression plasmids for DNA vaccine formulation; (2) assess the safety of the newly formulated vaccine when administered via the ocular route, and (3) assess the protection efficacy induced by the vaccine formulation after challenge with a virulent ILTV strain.
Control of infectious laryngotracheitis (ILT) by vaccination is a critical step in maintaining healthy and profitable poultry production. Nearly all long-lived poultry in the U.S. are vaccinated against ILT, typically using either a recombinant vaccine of the herpesvirus of turkey, fowlpox virus vectors, live attenuated vaccines of the chicken embryo origin (CEO) or tissue culture viral origin types, at times in combination.
The summary notes that live attenuated CEO vaccines may have drawbacks concerning regaining virulence, leading to performance penalties, yet they produce the best protection by diminishing virus shedding, which rapidly reduces the impact of disease outbreaks.
The summary adds that recombinant vaccines are a safer vaccination alternative against ILT because they do not become virulent during usage and, thus, can be safely administered in the hatchery, but it has been observed that their delayed immune response and inability to prevent viral shedding from the upper respiratory tract in the early stages of infection are limitations to their effectiveness.
Garcia and colleagues from the University of Georgia hypothesized that administering ILTV recombinant antigens by natural mucosal routes of viral entry may induce effective T-cell responses that can rapidly clear the virus and prevent further virus replication and shedding. Results highlighted the importance of boosting immunization to enhance the effectiveness of DNA immunizations. Neither the route (in ovo or eye drop), age, dose (single or double) or prime/boost strategies of plasmid administration induced a reduction of challenge virus replication.
The full research summary can be found on the USPOULTRY website. Information on other Association research may also be obtained by visiting the USPOULTRY website, uspoultry.org.
USPOULTRY, founded in 1947 and based in Tucker, Ga., serves its poultry and egg members through research, education, communications and technical services. The mission of the USPOULTRY Foundation is to support the recruitment and training of the brightest students, seek and fund scientific research, foster student scientists and promote careers in the poultry and egg industry.
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