Oral Immunization With Plant-Based Vaccine Induces a Protective Response Against Infectious Bursal Disease

Area of Science:

• Veterinary Virology
• Immunology
• Biotechnology

Background:

• Infectious Bursal Disease Virus (IBDV) causes significant economic losses in the poultry industry due to its immunosuppressive and contagious nature.
• A previously developed plant-based vaccine candidate protected against IBDV via intramuscular administration.

Purpose of the Study:

• To evaluate the efficacy of the plant-based IBDV vaccine candidate when administered orally.
• To determine if oral vaccination can elicit a protective immune response at the primary site of IBDV entry.

Main Methods:

• Chickens were vaccinated with two oral doses or an intramuscular prime followed by an oral boost.
• Immune response was assessed by virus-neutralizing antibodies, bursa/body weight ratio, T-cell infiltration, and viral load in the bursa.
• Vaccine efficacy was evaluated after challenge with IBDV.

Main Results:

• 85% of chickens receiving two oral doses and 100% receiving an oral boost after intramuscular prime developed virus-neutralizing antibodies.
• Oral vaccination schemes conferred protection against IBDV infection, indicated by improved bursa/body weight ratio and reduced viral load.
• While some mild bursal damage occurred, it was less severe than in unvaccinated, challenged controls.

Conclusions:

• The plant-based IBDV vaccine candidate is effective when administered orally, either through a prime/boost regimen or an oral boost following an intramuscular prime.
• Oral vaccination stimulates a specific and protective immune response against IBDV in chickens.
• This oral plant-based vaccine presents a viable and potentially advantageous alternative to conventional IBDV vaccines for the poultry industry.