From: http://www.dnaindia.com/report.asp?newsid=1213158


Scientists track how immune cells intercept parasites

Thursday, December 11, 2008 15:46 IST


WASHINGTON: The body's earliest responses to a group of parasites that cause illness, identified by researchers, will boost efforts to develop vaccines against them.

Scientists said that they tracked immune cells as they patrolled the second-shallowest layer of the skin in an animal model.

Injections of a genetically modified form of the parasite Leishmania Major caused them to turn from their patrols and intercept the parasites.

The same parasites are now infecting US soldiers on patrol in Iraq and Afghanistan, where sand flies, the insects whose bites spread Leishmania, are endemic.

The infections normally do not cause symptoms, but the parasite can reactivate and cause complications during pregnancy or if the immune system weakens, including skin sores, fever, damage to the spleen and liver and anemia.

"This is one of our most detailed looks so far at how a first responder in the immune system scouts out pathogens," said study co-author Stephen Beverley, Professor and head of the department of Molecular Microbiology at Washington University School of Medicine in St. Louis.

"Determining how the immune system reacts is critically important for efforts to develop vaccines that protect against these parasites," Beverley said.

What researchers learn from Leishmania also may have applications for controlling more harmful parasites from the same family of microbes, the trypanosomes, he added.

These include Trypanosomiasis, the cause of African sleeping sickness, which disrupts the lymph, circulatory and nervous systems and is fatal if untreated, and Chagas disease, which can damage the heart and the intestine in long-term infections, according to Washington release.

The paper was published online in Public Library of Science Pathogens.