Lots of mouse data says the thymus functions well in adults. Irradiated
mice reconsituted with bone marrow become noramlly responsive pretty
quickly, as do humans (about a year for people). Thymectomized mice
irradiated and bm reconsituted do not develope T cell funtion, so the
thymus must work even though it involutes.
On Tue, 21 Feb 1995, David Peritt wrote:
> In article <ralph.1143705994A at news.arizona.edu> Ralph M Bernstein,
>ralph at ccit.arizona.edu writes:
> >question: where the hell are those tcell being made? everyone knows that
> >aafter or at puberty the thymus involudes-we are left with a very poor
> >education system. w/out the thymic education we run the risk of
> >autoimmunity/ect. so what goes on here? it cannot be tcells that
> havenot
> >encountered antigen in the perhiphery, since they die in around 72h after
> >release if they dont encounter ag. evenbetter, i dont think it could be
> >from expanding memory cells because they would be infected any way-like a
> >roachmotel, in hiv infected lymphnodes, tcells go in but they dont go
> out.
>>> It is surmized with little data that peripheral T cells expand to fill
> the void. There is little evidence for extrathymic generation of new T
> cells (except for those gut g/d cells). Whether it is naive or memory T
> expanding is unknown to me. What I am saying is that I do not think it
> is known but yes it is a very basic immunology question. In fact, the
> reason I posted the homeostasis question was partially due to your
> question. If peripheral T's are proliferating they must get a signal to
> do so when T levels drop. What may that be???? This question could be
> answered by someone with nimble fingers willing to do the proper Tx
> experiments of naive and memory T in athymic mice. You put different
> amount of T in and see who proliferates to compensate. It may have been
> done but us human Immunologist never get to do many Tx exps and therefore
> never read these papers which can be done so elegantly partially out of
> jeolousy.
>>
