Many disease-causing microbes carry pumps that expel antibiotics, making the bugs hard to kill with standard drugs.
Ironically, these same pumps could be the bugs' Achilles heel.
University of California, Berkeley, scientists have found that the molecular pumps in Listeria bacteria, and perhaps in other pathogens, also expel small signaling molecules that stimulate a strong immune response in the cells they infect. A robust immune response, involving mobilization of killer cells and a host of other defenses, is needed to kill bad microbes before they can do damage
The surprising find that bacteria pump out a totally new and highly immunogenic molecule suggests that it may be possible to improve vaccines that use live or disabled bacteria to activate the immune system. These vaccine-grade bacteria could be engineered to ramp up production of the signaling molecule or ramp up the number of pumps, for example.
"We think this could translate directly into better vaccines," said Daniel Portnoy, UC Berkeley professor of molecular and cell biology and of public health and associate faculty director of the campus's Center for Emerging and Neglected Diseases. "We can certainly get Listeria bacteria to make more of this molecule; we already have a mutant that does that."
The researchers report their discovery, funded in part by the American Recovery and Reinvestment Act (ARRA) through the National Institute of Allergy and Infectious Diseases of the National Institutes of Health, in the May 28 issue of the journal Science.
For more than 20 years, Portnoy has been studying Listeria monocytogenes bacteria, which cause the serious foodborne illness listeriosis, to understand how they generate an unusually strong immune response in host cells. What he learns could help boost the effectiveness of a Listeria vaccine, but he also hopes to use the bacteria's powerful immunogenicity to boost the effectiveness of vaccine
|Contact: Robert Sanders|
University of California - Berkeley