Recognition of self vs non-self by macrophages?

[Ian A. York]

In article <Pine.3.07.9411051900.A21700-c100000 at alsys1> teitelba at aecom.yu.edu (Rachel Teitelbaum) writes:
>I think it might be worthwhile to mention anergy here too.  Even if a self
>peptide is preseted, odds are a second costimulation through alternate
>receptors (other than the TCR, eg CD28) are not supplied and the immune
>system is tolerized to that antigen.


        Do you mean in the thymus, or in the periphery?  If the former, I
agree with you; but if you mean that presentation of self-antigen is
different in any way from presentation of foreign antigen, I don't
agree.  After all, the same macrophage that presents foreign antigen is
simultaneously presenting self antigen, albeit on different MHC
molecules (which may or may not be derived from the same allele).  I
can't imagine that the macrophage will give the second signal to a
lymphocyte with a foreign-epitope-specific TcR, yet coyly snatch away the
signals from the self-reactive TcR.  If the lymphocyte is unable to
recognize the second signal, that's a different matter, and I had meant to
include that in the differentiation at the level of the T cell.
        Sorry if I misunderstand your comment.

Ian
-- 
Ian York   (york at mbcrr.harvard.edu)
Dana-Farber Cancer Institute, 44 Binney St., Boston MA 02115
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