Salmonella typhimurium Vaccine Candidate Delivering Infectious Bronchitis Virus S1 Protein to Induce Protection

Area of Science:

• Veterinary Virology
• Immunology
• Bacterial Vector Vaccines

Background:

• Infectious bronchitis (IB) poses a significant economic threat to the global poultry industry.
• There is a critical need for effective vaccines offering both safety and robust immune protection against IB.

Purpose of the Study:

• To develop and evaluate a novel vaccine candidate for infectious bronchitis (IB).
• To assess the immunogenicity and protective efficacy of a recombinant attenuated Salmonella Typhimurium vector expressing the IB virus S1 protein.

Main Methods:

• Constructed a recombinant attenuated Salmonella Typhimurium vector (χ11246(pYA4545-S1)) carrying the IB virus S1 gene.
• Confirmed high expression of the S1 protein in HD11 cells.
• Administered the vaccine candidate orally to chickens and evaluated immune responses and protection against IBV challenge.

Main Results:

• Oral immunization with χ11246(pYA4545-S1) successfully induced antibody and cytokine production, indicating an effective immune response.
• The vaccine candidate provided significant protection rates: 72% in the lacrimal gland, 56% in the trachea, and 56% in the cloaca against IBV infection.
• Vaccination significantly reduced histopathological damage in chickens challenged with infectious bronchitis virus.

Conclusions:

• The recombinant attenuated Salmonella Typhimurium vector expressing the IB virus S1 protein is a promising vaccine candidate for infectious bronchitis.
• This oral vaccination strategy offers a viable approach for enhancing poultry health and reducing economic losses associated with IB.
• The study presents a novel strategy for IB prevention, balancing host safety and immunogenicity.