re tolerance, real function and cortex present.

Ralph M Bernstein ralph at ccit.arizona.edu
Tue Jun 13 12:07:32 EST 1995


well brian, you wrote,

:From: bryan fisk <bryan_fisk at gyn.mda.uth.tmc.edu>
:Newsgroups: bionet.immunology
:Subject: Re: real function, type/tope, tolerance.
:Date: 13 Jun 1995 15:43:58 GMT
::Organization: University of Texas Health Science Center
:References: <ralph.1153368689A at 128.196.137.12>

:> then to dr fuchs question again

:>>Just because I cannot think of any way that the immune system can
:>>distinguish between idiotypes and foreign antigens does not mean that
>:>there is no such mechanism.  Therefore I repeat, can anyone provide me
:>>with an acceptable answer to this question?
:
:>     the tcells that are reactive to those identicle epitopes or 
:>idiotopes are deleted in the thymus.  these tcells dont reach the 
:>perhiphery to react with a b cell.
:
:>I thought T-cells were educated in the thymus upon thymic epithelium and 
:>not B-cells? Also, since each T- and B-cell has a clonotypic, rearranged 
:>receptor, from which idiotopes may arise, wouldn't each T-cell have to 
:>be tolerized against each B-cell idiotope? I don't see how that could be 
:>possible.

    yes upon thymic epithelium, but supposedly against self antigens.  the
tecs as well as the macrophages in the cortex may perform differential
presentation , perhaps presenting the same peptides in different ways from
all antigens in the thymus.  and since bcells can be in the thymus, their
antigen receptors may be presented and selected against.  
    __but_ the point actually is that tcells are mhc restricted, right?
right.  and dr fuchs point is that idiotypes can stim a response.  and since
only peptides, not idiotypes can be presented -thru mhc restriction- these
antigens (the recombining sites) are really irrelevant.  

    regards, ralph

Ralph M. Bernstein
Dept of Micro/Immuno
University of Arizona
Ph: 602 626 2585
Fx: 602 626 2100



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