Researchers have shown that amyloid beta, a slimy substance found in the brains of people with Alzheimer's disease, protects living mice and cultured human brain cells against brain infections.
The research could help speed up the search for methods for preventing or curing Alzheimer's.
Scientists have been speculating for years that infections and the immune system might have something to do with Alzheimer's.
Deepak Kumar and other scientists at Massachusetts General Hospital tested that idea in the lab by creating mice that were unable to produce amyloid beta. The scientists showed that the mice that could produce amyloid beta had a much easier time fighting off salmonella infections and yeast infections in the brain.
The scientists conducted a similar experiment using yeast, cultured human brain cells, and amyloid from the brains of people with Alzheimer's disease.
Genuine amyloid protected the human brain cells against the yeast infection, and it was about 1,000 times more effective than a synthetic version of amyloid, the researchers say.
Other research has implied that some people may develop Alzheimer's disease because, or partly because, they have a gene that interferes with the body's effort to clear old amyloid out of the brain.
