(300 WORDS MAX.) Interleukin-12 (IL-12) is a naturally occurring human protein traditionally associated with stimulation of immunity to bacterial and viral infections, and, because of its ability to inhibit formation of blood vessels in tumors, has been tested as an anti-cancer drug. We have demonstrated that when small levels of IL-12 are injected into mice with Alzheimer's disease, it stimulates immune-like cells in the brain resulting in disruption of plaques associated with progression disease. To greatly facilitate the translation of this finding into human clinical trials, we will examine the effect of IL-12 treatment in an aged dog model of Alzheimer's disease. These aged dogs develop dementia in similar fashion to humans. In addition, human IL-12 is active in dogs. The use of IL-12 as therapeutic biological drug for the treatment of Alzheimer's disease has never been attempted. As such, this represents a novel and potentially powerful approach to the treatment of Alzheimer's disease and other dementias.