They said their findings could ultimately lead to improved drugs to prevent or treat Salmonella infections.
The researchers found four genes related to the Salmonella's "molecular syringe" that are required for the bacteria to have maximum potency in infecting the worm, known as Caenorhabditis elegans. The virulence factors -- injected into the host cells by Salmonella -- act by blunting the innate immune system of C. elegans from attacking and destroying the infecting bacteria.
These findings are important, the researchers said, because the C. elegans innate immune response to Salmonella infection is quite similar to that of mammals, including humans. For this reason, the researchers said that their C elegans model can provide new genetic insights into the relationships between invading microbes and their target host cells.
The results of the Duke experiments were published June 8, 2004, in the journal Current Biology. The research was supported by the National Institutes of Health and the Whitehead Institute for Biomedical Research.
"C elegans lives in the soil, so it continually comes into contact with bacteria and other microbes," said lead researcher microbiologist Alejandro Aballay, Ph.D. "It has a highly developed system for not only recognizing bacteria, but also responding to them. The ability of its innate immune system to respond appropriately to specific bacteria is very similar to that of mammals.
"The goal of our research is not only to better understand what makes a particular pathogen harmful for the host, but to determine those characteristics of the host that either make it resistant or susceptible to the pathogen," Aballay added. "To be successful in this type of research, one cannot just focus on t
Contact: Richard Merritt
Duke University Medical Center