Immune cells are essential to the maintenance and repair in our bodies. However, an over-active immune system can lead to diseases such as arthritis, chronically inflamed wounds and atherosclerosis. Therefore, it is imperative to understand and carefully control our immune system activity. Our innate or non-specific immune system, acts as our body's first line of defence, these cells quickly reach the site, form a barrier, remove foreign material, and activate our more sophisticated adaptive immune system. Until now these non-specific immune cells were believed to act in a generic way unable to learn from previous infections. But new research from the University of Bristol shows that different experiences can dramatically change the function of these innate immune cells.Fanny Yuen interviewed Dr. Helen Weavers to find out more about how we can better control our immune systems.