Study uncovers how Salmonella avoids the body's immune response

Mar 14, 2012

UC Irvine researchers have discovered how Salmonella, a bacterium found in contaminated raw foods that causes major gastrointestinal distress in humans, thrives in the digestive tract despite the immune system's best efforts to destroy it.

Their findings help explain why is difficult to eradicate and point to new approaches for possible treatments. Most people infected with Salmonella suffer from diarrhea, fever and abdominal cramps for up to seven days before the infection resolves.

Lead researcher Manuela Raffatellu, a UCI assistant professor of & molecular genetics, and colleagues identified a novel molecular mechanism that allows Salmonella to survive. Results of their study appear in the March issue of Cell Host & Microbe.

Pathogens like Salmonella flourish and cause disease in humans through a process by which they acquire metal ions, such as zinc, from the body. One of the body's key immune responses is to flood the infected area with antimicrobial proteins that include calprotectin, which removes zinc. Without enough of this vital element, most pathogens eventually die.

Raffatellu's team found, however, that salmonellae overcome this immune response by expressing specialized transporter proteins that enable the bacteria to acquire zinc in spite of calprotectin reducing the amount available in the . This distinctive mechanism lets salmonellae continue proliferating.

At the same time, calprotectin inadvertently promotes Salmonella growth by killing the microbes that normally reside within the intestines and help the battle pathogenic bacteria.

"We're beginning to learn more about the mechanisms that allow pathogens like Salmonella to evade our natural defenses and make us sick," Raffatellu said. "In light of this, if we can devise therapies that block the acquisition of zinc and other metals by Salmonella specifically, we can fight this infection."

Additionally, she said, the new findings may have relevance for other illnesses, such as inflammatory bowel disease and colon cancer, in which high levels of calprotectin are detected.

Explore further: Shaking up cell biology: Researchers focus in on decades-old mitochondrial mystery

Provided by University of California - Irvine

5 /5 (2 votes)

Related Stories

Salmonella: Trickier than we imagined

Jun 13, 2008

Salmonella is serving up a surprise not only for tomato lovers around the country but also for scientists who study the rod-shaped bacterium that causes misery for millions of people.

Salmonella in garden birds responsive to antibiotics

Jun 02, 2008

Scientists at the University of Liverpool have found that Salmonella bacteria found in garden birds are sensitive to antibiotics, suggesting that the infection is unlike the bacteria found in livestock and humans.

Recommended for you

Scientists see how plants optimize their repair

16 hours ago

Researchers led by a Washington State University biologist have found the optimal mechanism by which plants heal the botanical equivalent of a bad sunburn. Their work, published in the Proceedings of the Na ...

Structure of an iron-transport protein revealed

23 hours ago

For the first time, the three dimensional structure of the protein that is essential for iron import into cells, has been elucidated. Biochemists of the University of Zurich have paved the way towards a better ...

Over-organizing repair cells set the stage for fibrosis

23 hours ago

The excessive activity of repair cells in the early stages of tissue recovery sets the stage for fibrosis by priming the activation of an important growth factor, according to a study in The Journal of Ce ...

User comments : 0