One of the most important tasks of the immune system is to identify what is foreign and what is self. If this distinction fails, then the body's own structures will be attacked, the result of which could be an autoimmune disease such as diabetes mellitus type 1 or multiple sclerosis. The only way to protect against these afflictions is to destroy all immune factors that turn against the body's own tissue in other words: immune tolerance. A team working with LMU researcher Dr. David Vhringer has now investigated exactly what role dendritic cells play in this process. There has long been suspicion that these cells, which are important for the body's defenses, are also essential for the establishment and maintenance of immune tolerance. "We investigated mice that lacked this cell type from birth," reports Vhringer. "It turned out that immune cells that attack the body's own tissue survive in these animals, and thereby trigger an autoimmune response. It follows that dendritic cells play a major part in protecting against autoimmune disease."
T cells are a type of white blood cell that are key actors in the body's immune defenses. Each T cell has a receptor on its surface for recognizing just one single antigen. Antigens are molecular structures, mostly fragments of proteins. T cells do not dock onto free antigens, however: they rely on other cells which can present antigens to them. It is the dendritic cells that are primarily responsible for this job. They present the T cells with various antigens, and if an antigen matches a receptor, then that T cell will trigger an immune response from the body.
This is how the body defends itself against pathogens and other intruders. But behind this tactic lies an element of danger to the organism: what happens if the antigen is not foreign, but originates from the body's own tissue instead? A wrongly induced immune response can lead to a severe autoimmune disease that, if left untreated, could lead to des
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| Contact: Luise Dirscherl dirscherl@lmu.de 49-892-180-2706 Ludwig-Maximilians-Universitt Mnchen Source:Eurekalert |