Am I missing something?
37_527 at uwovax.uwo.ca
37_527 at uwovax.uwo.ca
Thu Jul 2 23:12:52 EST 1992
In article (Date: 1 Jul 92 12:37:19 EDT) Nathan Maman (maman at titan.Colorado.
> I'm not an immunologist myself but I once read something about the
>self/non-self recognition. It was in a book written in '71 by Jacques
>Monod ``Hasard et neces site''. I think in english it should be ``Luck and
>necessity'' or something like that.
> As far as I remember well, he said in this book that the defense cells
>cannot``learn'' new types of ``strangers''. The process was described as the
>cell always trying to produce every antibody it knows. That is an explanation
>for different people having different capabilities concerning this subject of
>self defense. Also perhaps for auto-immune responses.
That's right. In B cell development, potentially all antibody specificities
can be made. Be cells are not 'instructed' to make certain specificities,
although I think that is what was taught in the mid 50s to early 60s (thus the
instructional theory of immune response).
> When the antibodies produced are unused, ie have not met the body
they match, the production is lowered.
Right again. If a B cell makes a useless antibody specificity then that cell
has is not maintained ie. brought into the expanded repertoire. Unless there
is some other reason such as idiotypic connectivity.
> And if on the contrary they matched
>then the production is increased. But the increase rate may be not high
>to insure a good defense. That's why, according to me, there is a
This is where the topic gets the most attention. Self antigen is around all
the time. Therefore a system is needed to tolerize self reactive B cells and
this is where the 'S' word gets used, and systemic/peripheral tolerance.
*** suppressor cells***
The various antibody specificities to any one particular foreign antigen are
selected for expansion based on the relative avidities for the antigen. High
avidity B cells are selected first and lower avidity lost (classical B cell
I think what Coutinho is trying to say is that self/non-self descrimination
cannot occur at the level of Ig gene rearrangement (antibody specificity)
and that there are other 'levels of organization' where B cells are trained
to be tolerant or can respond to a given antigen and this occurs (and may be
different) for the systemic and pheripheral immune system.
gdenomme at uwovax.uwo.ca
Dept. Microbiology and Immunology
University of Western Ontario
London, Ontario, CANADA
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