CCL22 and Alzheimer disease: To demonstrate that vaccination initiated in young 3xTg-AD mice without pre-existing AD-like pathology is beneficial as they age to 18±0.5 mo old, we measured spatial learning and memory in control (naïve or immunized with plasmid encoding MDC fused with irrelevant antigen) and immunized animals using the Morris Water Maze (MWM) [36].