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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...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
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,...
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T Cells to the Rescue
8 February 2006 (All day)
Who knew that a T cell could be so versatile? One kind of these immune cells, already thought to ease autoimmune disease and organ transplant rejection (ScienceNOW, 22 July 2004,), now appears to prevent atherosclerosis in mice. The work, although preliminary, may begin to explain how the immune system influences the potentially deadly disease.
An enduring mystery of atherosclerosis--the blockage of arteries that can lead to heart attack and stroke--is why T cells flock to atherosclerotic lesions, sites of inflammation lining blood vessels. For decades, scientists have wondered whether those cells are aggravating the disease or somehow countering it. Because regulatory T cells reduce inflammation in lab animals, cardiologist Ziad Mallat at the French National Institute of Health in Paris and his colleagues theorized that regulatory T cells are trying to protect against atherosclerosis.
The team tested the idea by irradiating mice to eliminate their T cells. Some of the animals received normal T cells back, and others got cells deficient in a surface molecule that activates regulatory T cells. All the mice were fed a high-fat diet for 20 weeks. Those without the surface molecule developed much more severe lesions, and higher numbers of them.
To ensure that a lack of regulatory T cells was the culprit, Mallat and his colleagues turned to a different set of mice that were devoid of T cells and genetically susceptible to atherosclerosis. Those given mature regulatory T cells didn't develop the disease. But mice that received regulatory T cells that were unable to activate and function properly suffered severe atherosclerotic lesions, the group reports in the 5 February online Nature Medicine.
The work "implicates this regulatory T cell as being involved in atherosclerosis," says Alan Daugherty, head of the cardiovascular research center at the University of Kentucky in Lexington. Still, he says, other groups have arrived at opposing results regarding the role of T cells in the disease, in part, perhaps, because their animal models aren't the same. Mallat hopes to clarify the role of regulatory T cells with a new experiment: injecting the cells into genetically normal mice with atherosclerosis, to see whether the cells can treat the disease.