Thus, in this study, we employed Aβ1–42 by intrahippocampal injection in rats to induce AD-associated changes, including disruption of spatial learning and memory, amyloid precursor protein (APP) and protein phosphatase (PP)2A expression, neuronal loss and apoptosis, glial cell activation, and proinflammatory and antiinflammatory T cell responses. The gene discussed is APP; the disease is Alzheimer disease.