Construction Of A Bivalent Vaccine Against

Escherichia coli causes a number of serious poultry diseases, including colibacillosis resulting inmillions of dollars lost to the poultry industry each year. Contamination of poultry products bySalmonella is a major public health concern. Development of a bivalent poultry vaccine directedagainst both of these bacteria would benefit the public health and increase poultry production. Orallyadministered attenuated S. typhimurium strains have been shown to provide excellent protection againstwild-type Salmonella challenge in chickens and systems for stable expression of heterologous antigensin such strains have been developed. Therefore, we will use attenuated S. typhimurium strains asdelivery vehicles for E. coli-derived surface antigens, thus eliciting an immune response against bothorganisms. Many iron-regulated proteins are ubiquitous among E. coli isolates, and others are directlycorrelated with pathogenic strains. We will target some of these as candidate antigens. Certain E. coliantigens will be characterized with regard to stability, growth properties, and, after oral inoculation ofchicks, the ability to colonize lymphoid organs and protect against challenge with virulent E. colistrains.