WEST LAFAYETTE, Ind. - Pathogenic listeria tricks intestinal cells into helping it pass through those cells to make people ill, and, if that doesn't work, the bacteria simply goes around the cells, according to a Purdue University study.
Arun Bhunia, a professor of food science, and Kristin Burkholder, a former Purdue graduate student who is now a postdoctoral researcher in microbiology and immunology at the University of Michigan Medical School, found that listeria, even in low doses, somehow triggers intestinal cells to express a new protein, heat shock protein 60, that acts as a receptor for listeria. This may allow the bacteria to enter the cells in the intestinal wall and exit into a person's bloodstream. Bhunia and Burkholder's findings were published in the early online version of the journal Infection and Immunity.
"It's possible that host cells generate more of these proteins in order to protect themselves during a stressful event such as infection," Burkholder said. "Our data suggest that listeria may benefit from this by actually using those proteins as receptors to enhance infection."
Listeria monocytogenes is a foodborne bacteria that can cause fever, muscle aches, nausea and diarrhea, as well as headaches, stiff neck, confusion, loss of balance and convulsions if it spreads to the nervous system. According to the U.S. Centers for Disease Control and Prevention, it sickens about 2,500 and kills 500 people each year in the United States and primarily affects pregnant women, newborns, older adults and those with weakened immune systems.
The findings suggest that listeria may pass between intestinal cells to sort of seep out of the intestines and into the bloodstream to cause infection.
"That can expedite the infection," Bhunia said.
Measurable increases of the heat shock 60 protein were detected when listeria was introduced to cultured intestinal cells.
Bhunia and Burkholder als
|Contact: Brian Wallheimer|