The body's innate immune system is a first line of defense, intent on sensing invading pathogens and wiping them out before they can cause harm. It should not be surprising then that bacteria have evolved many ways to specifically evade and overcome this sentry system in order to spread infection.
A study led by researchers in the University of Pennsylvania's School of Veterinary Medicine now reveals how some Salmonella bacteria hide from the immune system, allowing them to persist and cause systemic infection. The findings could help researchers craft a more effective vaccine against Salmonella.
Igor Brodsky, an assistant professor in Penn Vet's Department of Pathobiology, was senior author on the paper, which was published in the Journal of Experimental Medicine. Co-authors included Penn Vet postdoctoral associates Meghan A. Wynosky-Dolfi and Patrick J. Doonan, Ph.D. students Naomi H. Philip, Erin E. Zwack and Amber M. Riblett and department colleague Bruce D. Freedman. The Penn researchers collaborated with Till Strowig and Richard A. Flavell of Yale University School of Medicine and Maya C. Poffenberger, Daina Avizonis and Russell G. Jones of McGill University.
"Many of the same signals that are present in harmless bacteria are also present in pathogenic bacteria," Brodsky said. "One of the big unanswered questions is how does the innate immune system distinguish between the two? And, conversely, how have pathogenic bacteria evolved to get around the immune response?"
The Penn study addresses both questions, focusing on a component of the innate immune response called the inflammasome. Consisting of a complex of proteins that triggers the release of signaling molecules, the inflammasome serves to recruit other components of the immune system that can fight off the pathogen.
"We hypothesized that during the systemic phase of disease, Salmonella would have some way of avoiding i
|Contact: Katherine Unger Baillie|
University of Pennsylvania