Every cell has a specific task, including our immune system. This consists, among other things, of a large variety of blood cells, or white blood cells, the leukocytes. These cells make up a large part of our immune defense and are formed in the bone marrow. The main task of leukocytes is to defend against pathogens. Leukocytes are therefore an essential part of our immune system, protecting us from pathogens such as viruses, bacteria and parasites. The human immune system is not limited to one organ or part of the body. It affects many places throughout the body. The most important transport routes for immune cells and messenger substances are the bloodstream and the lymphatic vessels. The lymph fluid transports oxygen and nutrients to tissues and removes damaged or dead cells, pathogens and foreign substances. Our immune system thinks for itself. In order to be able to react more quickly to recurring threats, there is the acquired immune defense. The immune system acquired over the course of life reacts specifically from pathogen to pathogen; the immune system also remembers these and reacts more quickly and effectively the next time they come into contact. The immunological memory is created. Unfortunately, our innate immune system does not recognize some pathogens such as viruses or bacteria. These can therefore cause damage to the body. Now the so-called dendritic cells come into play: They also eliminate unknown pathogens and break them down. Particles of the pathogen envelope are transmitted to T cells. These special cells are familiar to almost every pathogen. The T cells multiply immediately and fight the pathogen. Furthermore, T cells in turn activate the B cells. These form exactly the right antibodies against a specific type of pathogen - the so-called antibodies. These antibodies bind to the respective pathogen and mark it so that it can be rendered harmless more quickly by the phagocytes.

What's special: B cells remember the nature of the pathogen. If the infection occurs again, the body can quickly produce suitable antibodies and defend itself.