Recognition of self vs non-self by macrophages?

Rachel Teitelbaum teitelba at aecom.yu.edu
Sat Nov 5 19:10:47 EST 1994


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.
-Rachel
teitelba at aecom.yu.edu

On 4 Nov 1994, Ian A. York wrote:

> In article <199411041533.HAA01434 at net.bio.net> kdelgert at vt.edu (Klaus D. Elgert) writes:
> >        A question arose in our graduate level immunology course.  "How do 
> >macrophages distinguish between self and non-self?"  Macrophages are 
> 
> I think there are two halves of your question: (1) How do macrophages 
> endocytose foreign rather than self antigen and (2) how do they present 
> foriegn material rather than self after endocytosis.  The short answer 
> is, they do not differentiate.  This is true particularly at the level of 
> presentation: self and foreign antigens are presented more or less at 
> random (i.e. if an antigen has the appropriate motifs and the other 
> caveats are met - cleavage, etc - then that epitope will be presented on 
> MHC molecules.  The discrimination here is at the level of the TcR; 
> although self-antigen is presented by macrophages, the T cells simply do 
> not recognize it.  (Well, it isn't "simple," I guess.)  
> 	As far as endocytosis is concerned, there is not very precise 
> differentiation here between self and non-self antigens.  There is some, 
> however.  As well as the opsinizing effects of antibody and complement, 
> there seems to be some recognition of different lipids.  I can't recall 
> the whole story on this, but for example during apoptosis there appears 
> to be alterations of the cell membrane, with a loss of the normal 
> assymetry of the membrane; the normally hidden lipids act as opsinins and 
> enhance phagocytosis.  This probably is part of the red cell situation 
> you mentioned.  I believe there may be other opsinins which are exposed 
> or prodced during apoptosis and probably other physiological states.  
> 
> Hope this helps.
> 
> Ian
> -- 
> Ian York   (york at mbcrr.harvard.edu)
> Dana-Farber Cancer Institute, 44 Binney St., Boston MA 02115
> Phone (617)-632-4328     Fax  (617)-632-2627
> 
> 






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