Langerhans Cells and Your Immune System
Langerhans Cells function where skin infection is present. They search the epidermis for invaders such as bacteria, infections or pathogens, where it is then absorbed, processed and presented as foreign bodies, named antigens, making them an “Antigen Presenting Cells”, APC
Paul Langerhans, a German pathologist, physiologist and biologist, is credited with the discovery of the Langerhans Cells, (LC). Langerhans Cells make up 1-4% of all epidermal cells and are derived from bone marrow. They are a class of dendritic cells named for their probing, finger like projections. They are a part of the immune system. They are present throughout the epidermis but are most prominent in the Stratus Spinosum and in the papillary layer of the dermis and reside around blood vessels.
The Langerhans Cells function where skin infection is present. They search the epidermis for invaders such as bacteria, infections or pathogens, where it is then absorbed, processed and presented as foreign bodies, named antigens, making them an “Antigen Presenting Cells”, APC. When Langerhans Cells detect antigens, they perform phagocytosis, drawing the bacteria, virus or infected cell inward while engulfing around it. During phagocytosis the pathogen is devoured. The intercellular digestion breaks down the pathogen into small particles. Each of these pieces is a potential antigen that can stimulate the immune system. The phagocyte uses a protein called Class l Major Histocompatibility Complex, (MHC), to present the antigen. It’s as if the phagocyte is calling out, “Look what I have!” Because of this important function, macrophages and dendritic cells are referred to as Antigen Presenting Cells, or APC.
Phagocytosis is an integral part of the immune system. Phagocytizing antigens allows the immune system to recognize what they are fighting against. After phagocytosis, Langerhans Cells transport a piece of the antigen they digested to the cell membrane. It is then presented to immune Helper T-cells. These Helper T-cells activate the immune system cells and unleash a response toward the antigen. The Helper T-cells activate B cells, which become antibodies.
Antibodies neutralize or make the viruses ineffective. Antibodies bind with surface proteins on the virus and block the effects of the antigen, by marking the bacteria for phagocytosis. The Langerhans Cells play an important roll in the protection of our skin. If only they helped with aging too.
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Written by The Institute of Skin Science