Tolerance vs Autoimmunity

psycler at netcom.com psycler at netcom.com
Tue Nov 15 10:58:07 EST 1994


Thomas C.M. Tung (tct8 at namaste.cc.columbia.edu) wrote:
: I was hoping that some of the scientists on this newsgroup can answer a 
: question I have regarding neo-class II MHC expression and its relative
: role in autoimmunity and induction of peripheral tolerance.

: In my immunology course, one mechanism that was cited for the induction
: of peripheral tolerance was the stimulation of TCR-CD4 by Class II MHC
: and self-peptides in the absence of the costimulatory CD28-B7 interaction,
: resulting in T-cell anergy.  Supposedly, this prevents cells other than
: professional APCs from activating T Cells, i.e. cells presenting peptides
: on Class II MHC w/o B7 induce anergy.

: Yet, one mechanism that is frequently given for autoimmunity is neo-class
: II expression on epithelial cell lines with presentation of self antigens
: that T cells were not tolerized to in the thymus.  This seems to be 
: inconsistent with the earlier theory on tolerance induction.  

: How are these divergent purposes served by the same mechanism?  
: It seems like g-IF, which induces neo-class II expression would also have
: to induce B7 expression too in order to cause autoimmunity -- is this 
: observed experimentally?

I don't believe that any documented experimental observations
have proven any theory on tolerance induction.  Are you
interested in theories or primarily experimental documentation?
To me, the two seem to be equally reliable because the immune system
is way more complex than any experiment can model and any
conclusion that is applied to tolerance is by far an
overgeneralization.  

Have you read Polly Matzinger's review, "Danger, Tolerance, and Immunity"
Annual Review of Immunology, 1994, from a volume released somewhere
around May of this year?  It's theoretical review and it challenges
the self vs. nonself model of tolerance very intelligently.
-- 
          Psycler                                        



More information about the Immuno mailing list