Immunologically privileged site
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2008-06-26T05:03:44Z
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An '''immunologically privileged site''' is any of those locations in the body--the [[brain]], [[anterior chamber]] of the eye, [[testis]], [[renal tubule]], [[uterus]], and possibly joints and [[adrenal glands]]--where immune response to [[antigens]] are not destructive to tissue or is suppressed. It is necessary due to unique self-proteins that reside only in particular tissues and do not travel through the [[lymphatic system]]. Examples of tissue-specific proteins include [[myelin]] of the [[central nervous system]]. Such proteins are sequestered in organs and extracellular fluid does not travel the lymphatic system, meaning they do not come into contact with T cells during [[negative selection]] in the [[thymus]]. [[Allografts]] to these sites are not rejected.
Immune response is modified by the privileged sites through anti-inflammatory cytokine release of [[TGF-beta]], which suppresses immune responses likely to cause tissue damage (favors [[B-cell]] [[antibody]] release vs. [[macrophage]] activation). Cells express [[FasL]] on their surface, which binds to [[cytotoxic T cells]] and causes the cytotoxic T cells to apoptose rather than destroy the tissue of privileged sites.
Medically, a [[cornea transplant]] is currently the only procedure that takes advantage of this.
==References==
* [http://microvet.arizona.edu/Courses/MIC419/Tutorials/autoimmunity.html http://microvet.arizona.edu/Courses/MIC419/Tutorials/autoimmunity.html]
* [http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=33671 http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=33671]
[[Category:Immune system]]
[[Category:Immunology]]
[[Category:Medicine stubs]]
{{immunology-stub}}