re re "new" immune / semantics

Ralph M Bernstein ralph at ccit.arizona.edu
Thu Apr 13 09:22:35 EST 1995


ok previously posted:

>>>"The problem comes when it's pointed out that we fail to make immune
>>>responses
>>>to the vast majority of antigens to which we are in frequent contact but
>>>which
>>>are not-self." 
>>>   
>>     I agree with this stmt (and the idea that the "over"simplification for
>>undergrads, ect, is too easy to get away with-but perhaps is basically true,
>>while there are always some exceptions occurring), but maybe some of this is
>>because alot of "things"(antigens) just arent immunogenic, as we know, but
>>it could be that they are "crossreactive" with the "self"antigens that the
>>lymphocytes were tolarized _against_.
 
>But this is precisely where we get into immunological semantics. 

exactly, this is semantics

>There are
>many antigens which are not "immunogenic" but which are "antigenic".> As
>an example if you inject human IgG (deaggregated) into mice they usually
>fail to mount an immune response. If you aggregate it or inject it into
>adjuvant they make a very strong response.
>Human IgG is obviously a foreign "antigen" to mice but it is not always
>an "immunogen".
>There are lots of molecules which it is possible to raise an immune response
>to under some circumstances but in general you have to present them in
>a special way to make them "immunogenic".

well, you are either immunogenic or not.(ill get hate mail for that
statement) antigens injected with adjuvant or aggregated as you point out
are now immunogenic, you have _altered_ their immunogenicity (increased it,
ect)-it goes along with the "nails in the coffin" theory, eg, is the signal
strong enough to elicit a signal, or does it confer anergy/apoptosis by
under or over stimulating.

what i was referring to in that post "
>but maybe some of this is
>>because alot of "things"(antigens) just arent immunogenic, as we know, but
>>it could be that they are "crossreactive" with the "self"antigens that the
>>lymphocytes were tolarized _against_.


was my attempt to explain that perhaps responses arent made to foreign
antigens _because_ they were crossreactive to antigens/ shapes that the
cells were tolarized against.  so a lack of a response is not just due to
"no injury" or "not-non-self" but, "oops, looks like what we deleted against
already"-eg crossreactive.  

but again, you are absolutly correct about the idea of an innate immunity
that is cooincidentally present in almost all extant vertebrates.  

regards ralph
Ralph M. Bernstein
Dept of Micro/Immuno
University of Arizona
Ph: 602 626 2585
Fx: 602 626 2100



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