My daughter has TS and my husband is type 1 diabetic, so this is very interesting:
Quote:
Regulatory T cells (also known as suppressor T cells) are a specialized subpopulation of T cells that act to suppress activation of the immune system and thereby maintain immune system homeostasis and tolerance to self. The existence of a dedicated population of "suppressor" T cells was the subject of significant controversy among immunologists for many years. However, recent advances in the molecular characterization of this cell population have firmly established their existence and their critical role in the vertebrate immune system. Interest in regulatory T cells has been heightened by evidence from experimental mouse models demonstrating that the immunosuppressive potential of these cells can be harnessed therapeutically to treat autoimmune diseases and facilitate transplantation tolerance or specifically eliminated to potentiate cancer immunotherapy.
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To function properly, the immune system must discriminate between self and non-self. When self/non-self discrimination fails, the immune system destroys cells and tissues of the body and as a result causes autoimmune diseases. Regulatory T cells actively suppress activation of the immune system and prevent pathological self-reactivity, i.e. autoimmune disease. The critical role regulatory T cells play within the immune system is evidenced by the severe autoimmune syndrome that results from a genetic deficiency in regulatory T cells.
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The molecular mechanism by which regulatory T cells exert their suppressor/regulatory activity has not been definitively characterized and is the subject of intense research. In vitro experiments suggest that suppressive mechanism requires cell-to-cell contact with the cell being suppressed. However, the immunosuppressive cytokines TGF-beta and Interleukin 10 (IL-10), produced by Th3 and Tr1 cells respectively, have also been implicated in regulatory T cell function.
An important question in the field of immunology is how the immunosuppressive activity of regulatory T cells is modulated during the course of an ongoing immune response. While the immunosuppressive function of regulatory T cells prevents the development of autoimmune disease, it is not desirable during immune responses to infectious microorganisms. Current hypotheses suggest that upon encounter with infectious microorganisms the activity of regulatory T cells may be downregulated, either directly or indirectly, by other cells to facilitate elimination of the infection. Experimental evidence from mouse models suggests that some pathogens may have evolved to manipulate regulatory T cells to immunosuppress the host and so potentiate their own survival. For example, regulatory T cell activity has been reported to increase in several infectious contexts, such as retroviral infections and various parasitic infections including Leishmania and malaria.
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http://en.wikipedia.org/wiki/Regulatory_T_cell