Immune privilege

Certain sites of the mammalian body have immune privilege (no immunity), meaning they are able to tolerate the introduction of antigens without eliciting an inflammatory immune response. Tissue grafts are normally recognised as foreign antigens by the body and attacked by the immune system. However, in immune privileged sites, tissue grafts can survive for extended periods of time without rejection occurring.[1] Immunologically privileged sites include:

Immune privilege is also believed to occur to some extent or able to be induced in articular cartilage.[2][3][4] This was once thought to also include the brain, but this is now known to be incorrect, as it has been shown that immune cells of the central nervous system contribute to the maintenance of neurogenesis and spatial learning abilities in adulthood.[5]

Immune privilege is thought to be an evolutionary adaptation to protect vital structures from the potentially damaging effects of an inflammatory immune response. Inflammation in the brain or eye can lead to loss of organ function, while immune responses directed against a fetus can lead to miscarriage.[6]

Medically, a cornea transplant[7] takes advantage of this, as does knee meniscal transplantation.[8]

  1. ^ Hong S, Van Kaer L (November 1999). "Immune privilege: keeping an eye on natural killer T cells". The Journal of Experimental Medicine. 190 (9): 1197–200. doi:10.1084/jem.190.9.1197. PMC 2195673. PMID 10544192.
  2. ^ Sun Z, Zhang M, Zhao XH, Liu ZH, Gao Y, Samartzis D, Wang HQ, Luo ZJ (2013). "Immune cascades in human intervertebral disc: the pros and cons". International Journal of Clinical and Experimental Medicine. 6 (6): 1009–14. PMC 3657352. PMID 23696917.
  3. ^ Fujihara Y, Takato T, Hoshi K (2014). "Macrophage-inducing FasL on chondrocytes forms immune privilege in cartilage tissue engineering, enhancing in vivo regeneration". Stem Cells. 32 (2): 1208–19. doi:10.1002/stem.1636. PMID 24446149.
  4. ^ Abazari A, Jomha NM, Elliott JA, McGann LE (2013). "Cryopreservation of articular cartilage". Cryobiology. 66 (3): 201–9. doi:10.1016/j.cryobiol.2013.03.001. PMID 23499618.
  5. ^ Ziv Y, Ron N, Butovsky O, Landa G, Sudai E, Greenberg N, Cohen H, Kipnis J, Schwartz M (February 2006). "Immune cells contribute to the maintenance of neurogenesis and spatial learning abilities in adulthood". Nat Neurosci. 9 (2): 268–75. doi:10.1038/nn1629. PMID 16415867.
  6. ^ Kent A (2009). "Why Doesn't a Mother Reject Her Fetus?". Rev Obstet Gynecol. 2 (1): 67–8. PMC 2672992. PMID 19399300.
  7. ^ Niederkorn, Jerry Y. (2017-01-27). "Corneal Transplantation and Immune Privilege". International Reviews of Immunology. 32 (1): 57–67. doi:10.3109/08830185.2012.737877. PMC 3885418. PMID 23360158.
  8. ^ Garrett JC, Steensen RN, Stevensen RN (1991). "Meniscal transplantation in the human knee: a preliminary report". Arthroscopy: The Journal of Arthroscopic and Related Surgery. 7 (1): 57–62. doi:10.1016/0749-8063(91)90079-D. PMID 2009121.