Professor Chris O'Callaghan tells us about the role of our immune system in vascular disease. The accumulation of fat in the arteries, such as cholesterol, can cause a thickening of the artery wall known as atherosclerosis. Professor Chris O'Callaghan is researching the role of the innate immune system in atherosclerosis to better understand immune responses to vascular disease. This may lead to improved treatments. Creative Commons Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales; http://creativecommons.org/licenses/by-nc-sa/2.0/uk/