====== Immune tolerance in pregnancy ======

Why doesn't an expectant mother's immune system damage her growing baby - since it has  'foreign' DNA?

This fundamental phenomenon has yet to be fully explained.

>During pregnancy, the maternal immune system is exposed to a major challenge. The fetus expresses paternal alloantigens, yet it is not rejected.\\ [...]\\ "Pregnancy represents a major challenge to immunologic tolerance. How the fetal 'semiallograft' evades maternal immune attack is unknown." \\ \\ Source : [[http://bloodjournal.hematologylibrary.org/content/117/6/1861.abstract|Journal of the American Society of Hematology]] vol. 117 no. 6 pp 1861-1868 {{:oa_padlock_grn.png?16&nolink|Open Access}}

It's known that a specialised type of immune response cell called //uterine Natural Killer cells// (uNK cells) play a part in suppressing the mother's immune response. They make up about 70% of the leukocytes (white blood cells) in the uterus during early pregnancy. Their precise function, method of action, and their origin, is currently unknown. (see [[http://www.ijdb.ehu.es/web/descarga/paper/082763jb|International Journal of Developmental Biology]]{{:oa_padlock_grn.png?16&nolink|open access}}54: 281 - 294)

Similarly, the developing baby also has its own (developing) immune system - which somehow accepts the presence of the mother's cells, even though they have differing DNA to its own.

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Also see : [[content:life_sciences:human_body:immunological_tolerance]]

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