Summary

Vaccine vectors are attenuated organisms that are used to deliver antigens from other pathogens. The expression of multiple antigens from the one vector means that a single vaccine can protect against a range of pathogens. Advantages of vectored vaccines include reduced production costs, simplified vaccination protocols and enhanced immunogenicity. Suprisingly, however, only a small number of vectored vaccines have been developed for the poultry industry. This pilot study aims to address this gap, using infectious bronchitis virus (IBV) as a model target.

In this project, antigens from IBV would be expressed in two contrasting vector systems:
1. A bacterial vector based on avian pathogenic E. coli (APEC) with defined, attenuating mutations in ion transport and regulatory genes
2. A virus vector based on infectious laryngotracheitis virus (ILTV) deficient in the virulence factor glycoprotein G
Controlled vaccination trials in SPF chickens would then assess and compare the ability of these two vectors to induce protection against challenge with IBV, APEC or ILTV.

Once this technology has been demonstrated, future projects can assess the ability of these vectors to deliver protective antigen from other significant pathogens. Simultaneously developing and assessing two contrasting vector systems (bacterial and viral) is a lower-risk strategy to identify effective methods for delivering protective antigens and developing new poultry vaccines.

Program

Chicken Meat

Research Organisation

The University of Melbourne

Objective Summary

Specific aims of this project are to…
1. Demonstrate that attenuated strains of ILTV and APEC are suitable vector delivery systems for poultry vaccines
2. Assess the vaccine efficacy of IBV antigen expressed by ILTV and APEC vaccine vector delivery systems
3. Facilitate future research that would apply this same vector technology to protect against a wide range of diseases

This project addresses objective 1 of the Chicken Meat Research and Development Plan 2009-14 (production efficiency for profit, climate change response and food security outcome). The project falls within the strategy that aims to develop additional, more efficient and lower cost disease prevention and control techniques for endemic, emerging infectious and non-infectious poultry diseases. This project will work towards achieving new control strategies for important endemic and emerging diseases by 2014.