Macrophages play a key role in the immune response, protecting organisms against infection and regulating the development of inflammation in tissue. Macrophages differ depending on where they are located and which tasks they perform. A scientist at TUM has been investigating whether these different types of cells have the same origin – and has come up with some surprising results. His findings reveal that there are two distinct macrophage cell lines that continue into adult life and that these two lineages have different origins. The research was recently published in Science magazine.