In article <1995Jan17.153755.9166 at newsserver.rrzn.uni-hannover.de>,
<nhchpelt at rrzn-user.uni-hannover.de> wrote:
>What I always wanted to know but never found any information about is:
>>Why is an embryo not regarded as foreign tissue to a pregnant mother?
>Why does the maternal immune system tolerate it?
>Doesn't the embryonic tissue express any antigens/MHCs which could stimulate
>the mother's immune answer?
>>Sorry, I'm no expert in that field (but I have some knowledge of basic
>immunology).
>I would therefore appreciate any answer or hints to scientific publications.
>>Thank you in advance.
>>Juliane Meyerhoff
>Department of Chemical Engeneering
>University of Hannover /Germany
>>nhchpelt at rrzn-user.uni-hannover.de>
I believe that this is mainly due to the fact that the mother's cellular
immune system has no access to the baby (and much of the immune response
relies on cell-cell interactions). Thus, the only interactions can be with
soluble antigens, which should not differ significantly from mother to baby.
One big exception is the Rh factor. If the mother is Rh- and a baby is Rh+,
then a primary antibody response is generated. However, IgM (the main
antibody type in a primary response) cannot cross the placenta, so the child
is safe. If a second Rh+ baby is produced, however, a secondary response is
elicited. Since IgG (the main antibody in a secondary response) *can* cross
the plancenta, this can cause "rejection" of the fetus, resulting in a
miscarriage.
BioKen
--
Ken Frauwirth (MiSTie #33025) _ _
frauwirt at mendel.berkeley.edu |_) * |/ (_ |\ |
Dept. of Molec. & Cell Bio. |_) | () |\ (_ | \|
Univ. of Cal., Berkeley Push the button...someone :(
