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The difficulty in making a vaccine against Salmonella and E. coli is related to their genetic diversity. If the Curtiss research team is to be successful, the vaccine must be effective against a broad spectrum of E. coli and Salmonella groups.

In the past decade several researchers and commercial enterprises have developed Salmonella vaccines for animal health, but they are only effective against a few strains.

The Curtiss group has been a world leader in Salmonella-based vaccines. Curtiss’ international team alone has already developed two vaccines that are effective against Salmonella in livestock. By freeing animals from Salmonella, the vaccine is designed to prevent it from traveling down the food chain to people. His vaccine has received FDA approval for use with swine and poultry and is on the market.

The first step in vaccine development is to understand the molecular tricks bacteria use to elude a host’s immune system. Within the haystack of the E. coli bacterial genome, the research team has been focused on identifying the genes responsible for triggering its harmful effects.

But in order for the APEC vaccine to pull double duty, they must also demonstrate effectiveness against Salmonella. A key challenge of the project is to see if there is a common thread that can be found in E. coli and Salmonella-which genetically, are very distant cousins at best.

“The problem right now is understanding the virulence of APEC as well as Salmonella to find a way that will protect against all types of the bacteria,” said Mellata.

For the past generation, Curtiss has employed Salmonella as a Trojan horse against a variety of harmful pathogens. By using a similar approach, his team is currently developing a vaccine against bacterial pneumonia in a $15 million project funded primarily by the Bill and Melinda Gates Foundation.

For the USDA project, the APEC genes would be shuttled into the Salmonella bacteria in the hopes of triggering a protective immune response against both Salmonella and E. coli.

Mellata feels her team has many APEC gene targets they will use, and they are hard at work to identify several promising factors. The team hopes to have several candidates to test at the end of the three-year, $400,000 project, which will be completed in 2010.

About the Biodesign Institute at ASU

The Biodesign Institute at Arizona State University pursues research to create personalized medical diagnostics and treatments, outpace infectious disease, clean the environment, develop alternative energy sources, and secure a safer world. Using a team approach that fuses the biosciences with nanoscale engineering and advanced computing, the Biodesign Institute collaborates with academic, industrial and governmental organizations globally to accelerate discoveries to market. The institute also educates future scientists by providing hands-on laboratory research for more than 200 students per semester. For more information, go to: www.biodesign.asu.edu