re^5 real funct, idiotype, confusion
psycler at netcom.com
Fri Jun 9 22:08:20 EST 1995
Ralph M Bernstein (ralph at ccit.arizona.edu) wrote:
: ok, epram fuchs posted:
: i think that you are confused between the immuneresponse to lps (a
: mitogen, an epitope) and the immuneresponse to a whole bacterium (many many
: many epitopes (EPITOPES, not idiotopes), and the immuneresponse's ability to
: process and present antigens as well as the ability of t cells to activate
: and tolerate b cells, (and viceversa)(and also forgetting basic medical
: microbiology, such as gram negative vaccines, etc).
Just a few comments in passing...I underscored 'an' because from my
experience in perusing the Sigma catalog, lps, or lipopolysaccharide, aka
endotoxin, comes in all forms, shapes and sizes; therefore 'an' is an
inappropriate comparison determinant, since it should be 'some' or plural.
Hence your argument would read...lps (many many epitopes), whole bacteria
(many many epitopes)...it does make a difference you see...
: >The problem I have with this answer is:
: >1) At least some B cells present their idiotypes (I confess, I don't know
: >the fraction) ^
:no b cells present their idiotopes. they cannot. look up anything on
:antigen presentation and antigen processing.i feel i am belaboring this point.
Notice the two underscores: EJF wrote idiotypes and you reiterated idiotopes.
Yet both are different and the difference is critical within the context
of ideas exchanged on this subject.
: >2) Many of these B cells that do present their idiotypes will become
: >activated in the course of their lifetimes
: >3) If an activated B cell can activate a naive T cell, an autoreactive T
: >cell that cross-reacts on that B cell idiotype could do a lot of damage.
: >As rare as you think such a situation may be, it only takes one encounter
: >of an autoreactive T cell with a B cell presenting a cross-reacting
: >idiotype during the entire lifetime of the animal to do (possibly)
: >significant and potentially lethal damage.
: i think you are forgetting your basic immunology. _one_ autoreactive
: tcell is probably suppressed and deleted in the perhiphery. but even if it
: proliferated like crazy who is to say that this (__if you substitue epitope
: for "idiotope", and then you are _simply_ describing network theory, _not_
: something new__) doesnt happen? what is autoimmunity anyway?
: crossreactions, and basically mistakes, ms, diabetes, etc.
I disagree with those last few statements regarding the nature of autoimmunity.
Wekerle; Hafler and Weiner have all shown that autoimmune T cells can
be isolated from healthy individuals. Concluding that autoimmunity is
some form of disease, or a basic mistake, therefore is a gross and inaccurate
generalization. True, when we study MS, MG, IDDM, lupus, we find autoimmune
reactions. But the leaders in the field of autoimmunity have now well
established that these autoimmune reactions are not restricted to diseased
individuals -- they are present in ALL individuals. It's my educated
guess that so-called 'autoimmune' disease results from imbalances
within these autoimmune networks; yet the autoimmunity itself plays
an active role in the regulation of immunity which could be explained
by a massive network of idiotopic-anti-idiotopic reactions (notice
the absence of the word 'idiotypic').
: selectively answering and raising new points doesnt help analyze your
: theory, it just creates flamboyant waves. really this idea could be used to
: look at the origins of the vertebrate type immune response, but these basic
: questions are probably important to other basic immunologists as well.
: regards, ralph
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