Something unknowable in immunology? Simple logic?
dfonseca at mail.sas.upenn.edu
Thu Jan 20 17:52:02 EST 1994
A recent post stated:
I can see that the rate of antigen experience by T cells is
greatest when younger, but this ignores the fact that new TcR and Ig
are generated right up until the day you die. Since antigen receptor
generation is essentially a random process it is inevitable
that cells with self-reactive receptors will emerge from the bone marrow
all throughout life. If the thymus involutes after
puberty, where are all these new cells getting their education
(both in +ve and -ve selection)?
Is this really a problem? If the thymus involutes, then
no T cells will be made i.e. no positive selection.
As no T cells are made, it does'nt matter that there
is no negative selection either.
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