What is an antigen?

[Mike Clark]

In article <4nf69k at news-ipg.umds.ac.uk>, NORMSKI
<mailto:p.norman at umds.ac.uk> wrote:
> ssharif at uoguelph.ca (Shayan Sharif) wrote:
> >An antigen, by definition, is a substance which binds to an antibody 
> >molecule.
>   So Fc receptors and complement in their normal environment are antigens are they? hm
> mm
> 
> An antigen is not a substance that binds to an antibody, but a substance which leads t
> o the 
> production of antibody (greek:- genan- to produce)
> 
> do I win pedant of the week award  ?  

No ! :-)

> 
Well to be pendantic (and see my other posting to this question) what
you describe is an immunogen and not an antigen. Antigens are able to
bind to the specific binding site in the Fab of an antibody. Not all
antigens are however immunogenic!
As to a substance which leads to the production of antibody I can think
of other things such as B-cell mitogens (which may or may not be an antigen
for the particular Ig on the particular B-cell triggered).



Mike Clark, mrc7 at cam.ac.uk          http://www.path.cam.ac.uk/~mrc7/
-- 
  o/ \\    //            ||  ,_ o   Dr. M.R. Clark, Division of Immunology
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