When there is an infection, phagocytes move to the bacteria by sensing chemicals. These chemicals may come from bacteria or from other phagocytes that are already there. The phagocytes move by a way called chemotaxis. When bacteria touch a phagocyte, they bind to the receptors on the phagocyte and are eaten (phagocytosed). When bacteria enter some phagocytes, the phagocytes use oxidants and nitric oxide to kill the pathogen. After phagocytosis, macrophages and dendritic cells can also do 'antigen presentation': this is when the phagocyte moves parts of the killed bacteria back to its surface. These parts are then shown to other cells of the immune system. Some phagocytes then move to the body's lymph nodes and show the bacterial parts to white blood cells called lymphocytes. This action is important in getting immunity.