Strands of beta amyloid fibrils form around yeast in culture media. (credit: Credit: D.K.V. Kumar et al. / Science Translational Medicine (2016)])

The protein globs that jam brain circuits in people with Alzheimer’s disease may not result from a sloppy surplus, but rather a bacterial battle, a new study suggests.

Previously, researchers assumed that the protein—beta amyloid—was just a junk molecule that piled up. And efforts to cure Alzheimer’s focused on clearing out clogs and banishing beta amyloid from the brain. But a new study conducted using mice and worms suggests that the protein clumps are actually microbial booby traps, sturdy proteinaceous snares intended to confine invading microbes and protect the brain.

The findings, published in the journal Science Translational Medicine, suggest that Alzheimer’s may result from the brain’s effort to fight off infections. While that hypothesis is controversial and highly speculative at this point, it could dramatically alter the way researchers and doctors work to treat and prevent the degenerative disease.