Immune defence in the lymphatic system of the skin

As the interface organ between the body and the external environment, the skin is predestined to have frequent and intensive contact with pathogens and therefore possesses a particularly well-developed immunological defence. The immune system protects the body’s integrity with innate components such as the skin’s physicochemical barrier function, the phagocytic cells and the complement system. The network of Langerhans dendritic cells in the epidermis allows immediate detection and rapid transport of antigen material to the regional lymph nodes and the triggering of a specific immune response by T and B cells. For immunological processes, the passage through the lymphatic system is decisive, as diverse interactions occur between cells and the lymphatic system. On the one hand, the interaction of dendritic receptors with antigenic structures triggers intracellular signals, allowing migration through the lymphatic system to the lymph node via chemokines and chemokine receptors. On the other hand, the Langerhans dendritic cells alter their own phenotype during migration through the lymphatic system: they lose their ability to phagocytise in favour of the increased synthesis of MHC molecules and become antigen-presenting cells.