Aging is a dominant risk factor for atherosclerotic cardiovascular disease and is associated with compositional and functional changes in our immune system, called immunosenescence. To gain insights into the impact of immunosenescence on atherosclerosis, we investigated plaque development and the immune landscape in an AAV-PCSK9 mouse model. Young (3 months) and aged (18 months) male C57Bl/6 mice received a single i.v. injecti...