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/Source:/       *Yale University*       
/Date:/         2005-02-08
/URL:/  http://www.sciencedaily.com/releases/2005/02/050205105557.htm

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   Infectious Agent Linked To Mad Cow Disease Found In Organs Other
   Than The Brain

New Haven, Conn. -- Prions, infectious proteins associated with bovine 
spongiform encephalopathy (BSE) or Mad Cow Disease, were previously 
thought to accumulate mainly in the brain, but Yale and University of 
Zurich researchers report in Science that other organs can also become 
infected.

Past research had shown that the brain and spinal cord bear the highest 
infection risk for BSE, followed by organs such as the spleen, lymph 
nodes and tonsils. All other organs were thought to be devoid of prions.

Ruddle and co-authors analyzed three organ systems that are typically 
free of prions: liver, pancreas and kidney, in five different mouse 
models of chronic inflammation. After the mice were infected with 
prions, the team detected prion accumulation in the inflamed organs. 
They concluded that the spectrum of organs containing prions might be 
considerably increased in situations of chronic inflammation.

“The study suggests that the current prion risk-classification of farm 
animal organs may need to be reassessed in animals suffering from 
inflammation due to microbial infection or autoimmune disease,” said 
Nancy H. Ruddle, the John Rodman Paul Professor and Director of Graduate 
Studies in the Department of Epidemiology and Public Health at the Yale 
School of Medicine.

Previous research in Adriano Aguzzi’s group at the Institute of 
Neuropathology at University of Zurich showed that B cells are essential 
for the spread of prions to organs other than the brain. B cells are 
found in lymphoid organs in healthy humans and animals, but they can 
migrate into non-lymphoid organs under inflammatory circumstances.

Other researchers on the study include first author Mathias 
Heikenwalder, Nicolas Zeller, Harald Seeger, Marco Prinz, 
Peter-Christian Klohn, Petra Schwarz, Charles Weissman and the director 
of the study, Adriano Aguzzi.

Ruddle’s portion of this study was supported by National Institutes of 
Health Grant CA 16885.

Citation: Science, Online Publication: January 20, 2005. Print 
Publication: February 18, 2005.

*Editor's Note:* The original news release can be found here 
<http://www.yale.edu/opa/newsr/05-01-25-01.all.html>.

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/This story has been adapted from a news release issued by Yale University./