Before Elan's study, "there were a lot of reasons to think not only that [vaccines] shouldn't be done but that they would make things worse," says Dale B. Schenk, the company's vice president of discovery research. The prevailing wisdom was that disease-fighting antibodies, which vaccines stimulate, couldn't penetrate the blood-brain barrier. If antibodies did sneak into the brain, the fear was that they would trigger a massive, unhealthy immune response.
Schenk recalls that the vaccine study consequently had a "very low priority" at Dublin-based Elan. But he eventually mustered a large team that discovered the benefits to vaccinating an AD mouse model with b-amyloid (Ab), the peptide that aggregates into amyloid plaques in Alzheimer brains. Mice that started receiving intramuscular injections when six weeks old didn't develop plaques and other neuropathology. Vaccinations begun at 11 months of age sharply reduced pathology, with plaques in the frontal cortex plunging 84% compared ...
