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5 December 2013 11:26 am ,
Vol. 342 ,
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
Since arriving on the island of Guam in the 1940s, the brown tree snake ( Boiga irregularis ) has extirpated native...
An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
- 5 December 2013 11:26 am , Vol. 342 , #6163
- About Us
Killer Cells Get a Boost
1 July 2005 (All day)
White blood cells help our bodies fight infection by killing harmful bacteria. Now researchers have discovered how these cells turn their weapons on and off. The findings may give doctors a powerful new tool for boosting a patient's immune system.
White blood cells have a high-stress job. Infected tissues teem with dangerous bacteria that drive down oxygen levels by destroying surrounding blood vessels. When the cells reach the bacteria, they attack them with antimicrobial compounds like nitric oxide and cathelicidins--proteins that poke holes in bacterial membranes.
But white blood cells don't need to make killer compounds all the time. Otherwise they might destroy good cells while wasting precious energy. So biologist Carole Peyssonnaux, microbiologist Victor Nizet, and colleagues at the University of California, San Diego, investigated how the cells might regulate their protective behavior. The researchers found that, in mice, white blood cells make a protein called HIF-1 that revs up the production of antibacterial compounds when oxygen levels begin to drop, or when the cell encounters a harmful bacterium. In contrast, HIF-1's activity is reduced when the cells are circulating through the oxygen-rich blood stream.
To determine HIF-1's role in fighting infection, the team engineered mice that were incapable of producing the protein in their white blood cells. Compared to normal mice, mice without HIF-1 had 1000 times more bacteria in their body post-infection and developed skin legions that were twice as big, the team reports today in the Journal of Clinical Investigation.
"Turning on HIF-1 is like a white blood cell pulling out its sword as it enters infected tissue," says Nizet. If the protein works the same way in humans, he notes, it may be possible to augment the body's natural infection fighting abilities. As opposed to using medicine as an antibiotic, he says, we might one day have a pill that increases the levels of HIF-1 in white blood cells.
The authors are the first to show how HIF-1 regulates a white blood cell's bacteria-fighting abilities, says microbiologist Kol Zarember, a research fellow at the National Institutes of Health. "This demonstrates a very important mechanism for boosting the immune system."