Possible Alzheimer Vaccine Found
by
Malcolm Ritter,
AP Science Writer

December 21, 2000 (AP) -- The research was conducted by two independent research teams, centered at the University of South Florida in Tampa and the University of Toronto in Ontario, Canada. The studies used strains of mice that develop lots of amyloid plaques in their brains, along with measurable memory deficits, because of the genes they carry. The researchers used different versions of a procedure in which mice swam until they learned the location of an underwater platform. The animals were then tested to see how well they remembered where the platform was. Alzheimer's patients frequently have trouble remembering locations and how to get to destinations.

Both studies found that mice that had been repeatedly vaccinated performed markedly better than the untreated plaque-forming mice in the memory tests. On some occasions they did as well or nearly as well as ordinary mice. University of South Florida researcher Dave Morgan said his vaccinated mice were slower to learn the platform location but eventually remembered it as well as ordinary mice did.

This past July, drug company scientists announced that preliminary results in human patients indicated the vaccine was safe. Those tests were not designed to assess any effect on symptoms. Human tests are continuing under the sponsorship of Elan Corp. of Dublin, IRELAND, and American Home Products Corp. of Madison, NJ. Neither company paid for the new mouse studies. The researchers who carried out the mouse studies said it is not clear why the vaccine protects memory. For one thing, the research does not settle the question of whether the plaques actually cause the symptoms of Alzheimer's.

The vaccine was designed to make the mouse immune system attack amyloid-beta peptide, also called beta amyloid, a key component of the brain plaques in Alzheimer's. And both studies found that vaccinated mice had fewer and smaller amyloid plaques in their brains. But Morgan noted that his treated mice still had a lot of plaques. He and Dr. Peter St George-Hyslop, one of the University of Toronto researchers, suggested the vaccine might act on a harmful form of amyloid-beta peptide outside of the plaques.

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On the Web:

Azheimer's Association: www.alz.org.