Embargoed by Science until 1 p.m. CDT Thursday, June 1
Contacts:
Jesse Goodman, M.D., (301) 4356-5680, (301) 717-0696
Michael Herron, (612) 624-1159
Teri Charest, Academic Health Center, (612) 624-4604 [email protected]
U OF MINNESOTA SCIENTISTS IDENTIFY TARGET OF EHRLICHIOSIS BACTERIUM; KEY STEP TOWARD VACCINE OR NEW DRUGS
MINNEAPOLIS / ST. PAUL--University of Minnesota researchers have identified the molecule on human cells that binds to the bacterium responsible for human granulocytic ehrlichiosis (HGE), a tick-borne illness recently discovered in Minnesota. The finding, published in the June 1 issue of Science, gives scientists a promising target for the development of a vaccine against the disease as well as new drugs that might be useful in treating a variety of disorders.
The ehrlichiosis bacterium is delicate in that it cannot survive outside of a cell. It is unique because it infects the very cells of the body that are usually best at killing bacteria: white blood cells called neutrophils. "We now understand how this stealth parasite is able to bind to white cells and enter them safely, avoiding being eaten and killed," said Jesse Goodman, professor of medicine and an author of the report. "This research has essentially located a lock on the cell, and we know this bacterium holds a key. The next step is to find the key so that we can not only protect against this disease, but potentially find new approaches to stimulate or turn off white blood cells when necessary for treatment of other diseases."
"This discovery is important both with respect to designing vaccines against this uncommon disease and in helping identify and understand a new pathway that appears to be able to regulate how white blood cells function," said Michael Herron, assistant scientist in the department of medicine and one of the authors of the article.
As is the case with the bacteria that cause Lyme disease, this bacterium is transmitted to humans through a deer tick bite. Ehrlichiosis is easy to treat using tetracycline antibiotics, though it is difficult to diagnose. Anyone experiencing high fever with headache, fatigue or muscle aches after exposure to ticks should see a physician. Symptoms usually appear within a few days after a tick bite. Related bacteria can also cause a similar disease in horses, cats and dogs.
Approximately 1,000 cases of HGE have been reported, primarily in the northeastern United States, as well as in the Upper Midwest, where Lyme disease is common. Johann Bakken first reported the disease in Minnesota in 1994, and the bacterium was first isolated in Goodman's laboratory in 1995.
The other authors of the Science report are Curtis Nelson and Janet Larson from the University of Minnesota, and Karen Snapp and Geoffrey Kansas from Northwestern University.
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