NEW YORK, June 12 (UPI) -- U.S. researchers said Tuesday they have discovered an antibody in the blood that could prove to be a natural defense against Alzheimer's disease.
A team at NewYork-Presbyterian Hospital/Weill Cornell Medical Center said the newly found antibodies appear to selectively target aggregates of beta amyloid proteins -- toxic to brain cells and believed to be the main culprits in causing Alzheimer's -- while ignoring the harmless, single-molecule forms of the same proteins.
The study marks the first definitive proof that such antibodies exist in substantial quantities in human blood, the researchers said. The researchers said they stumbled across the mysterious antibodies while testing a potential new immunotherapy for Alzheimer's called Intravenous Immunoglobulin.
"The effects of IVIG in lowering beta amyloid levels in Alzheimer's patients in our phase 1 clinical trial were much more profound than we expected," said lead researcher Norman Relkin. "We couldn't readily explain this based on the low levels of anti-amyloid antibodies known to be present in IVIG. We suspected there might be another, unseen player."
The antibodies seem to be able to pick out the toxic "clumps" of beta amyloid proteins and tell them apart from the single-molecule proteins due to the clumped proteins' misfolded shape.
"That was a surprise, because most antibodies work by recognizing some aspect of the chemical structure of their target -- not their shape," said study co-author Paul Szabo. "The antibodies recognize a particular shape that proteins assume only when they become these toxic aggregates."
The new discovery was presented this week at the 2nd Alzheimer's Association International Conference on Prevention of Dementia in Washington.
