Dr. Alan MacDonald has done extensive work on this subject:
alzheimerborreliosis.net/research/ Some of his work has been duplicated now too:
/spirodementia.wordpress.com/drexel-university-team-duplicate-dr-alan-macdonalds-findings-of-bacterial-biofilms-in-alzheimers-plaques/ And from what I've read further, the thinking is that amyloid plaques are the body's attempts at repair - this isn't the article I was reading, but it still shows the science behind it:
"One of Colton’s key insights into Alzheimer’s disease came from an unusual source—the body’s defense mechanisms against a liver parasite. Macrophages, giant immune cells that neutralize threats throughout the body, can exist in either a repair mode, in which they wall off the threat and preserve the body’s healthy cells, or in a toxic mode, in which they destroy the invader as well as healthy cells caught up in the attack. The mode typically depends on the urgency of the threat, and a parasite would usually be dispatched swiftly with a toxic response. However, in this case, the liver parasite communicates with the macrophages and convinces them to enter the repair phase instead. As a result, the macrophages wall off the parasite, protecting the body but allowing the parasite to survive.
Colton posited that a similar process could be taking place in the brain. Her team identified genes that would indicate whether microglia were in the repair or toxic phase when amyloid deposits began to form. In tests using mice with an Alzheimer’s-like condition, they found that the microglia did not attack the amyloid deposits; as with the liver parasite, the deposits remained intact and accumulated."
/neurology.duke.edu/about/news/unlocking-alzheimers-disease