Genetic memory vs natural selection

Mike Clark mrc7 at cam.ac.uk
Tue Oct 12 07:03:37 EST 1999


In article <7tnpfo$cji$1 at oceanite.cybercable.fr>, Pierre
<URL:mailto:sonigo at cochin.inserm.fr> wrote:
> 
> Interesting point.
> Your hypothesis requires that individuals with high affinity antibodies to
> blood group molecules had a selective advantage. Some antibodies protect
> against the rhesus incompatibility problem during pregnacy. Is it what you
> suggest ?
> 
> 
> 
No I was not referring to RhD. This is an example of a T-dependent protein
antigen.

I was referring mainly to anti-carbohydrate responses such as for
example the blood groups A and B. Virtually everyone has the capacity to
make these same antibodies using similar inherited sets of V-genes. However
the auto reactive antibodies which would bind to your own blood group are
not selected leaving you with humoral immunity to the other blood groups.
The commonly accepted dogma is that these antibodies are cross reactive on
bacterial carbohydrates and hence protect us from infection ie they are not
actually generated by immunisation through encounters with blood group
differences. For some reason there is both a set of commonly inherited
blood group antigens (encoded by glycosyl transferases) and also a set of
commonly inherited V-genes which have the potential to be specific for
them.

Mike Clark,                        <URL:http://www.path.cam.ac.uk/~mrc7/>
-- 
 o/ \\    //            ||  ,_ o   M.R. Clark, PhD. Division of Immunology
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