APOE and atherosclerosis: More direct and convincing evidence for a role of adaptive immunity in atherosclerosis has been provided using experimental mouse models of atherosclerosis, especially Apolipoprotein E (Apoe)−/− or low-density lipoprotein receptor (Ldlr)−/− mice, in which human-like atherosclerotic lesions develop spontaneously or in response to a high-fat diet.