ouchterlony immunodiffusion

C. Allen Black, Ph.D. info at sunpillar.com
Mon Dec 9 23:02:27 EST 2002


In article <20021210030856.5919.qmail at ww02.hostica.com>,
 drrodriguez at hotmail.com wrote:

> A child has severe hay fever.  A total IgE measurement was performed by the 
> Ouchterlony immunodiffusion method.  No lines of precipitation appeared on 
> the immunodiffusion plate.  What is the most likely explanation for this 
> event?
> 
> 
> 
> so is no precipitation possible?  if so, what's going on here?  someone, 
> anyone?
> 
> thanks.
> 
> http://biowww.net/mynews/tree.php?group_name=bionet_immunology&begin=0

Yes, it is entirely possible that precipitation might not occur, if the 
amount of antibody greatly exceeds the amount of antigen.  

Precipitation is based on antibodies being multivalent and, thus, 
crosslinking the antigen until it precipitates.  If there is a great 
excess of either the antigen or antibody, then the antibody binds to 
only one molecule and will remain soluble and not precipitate.

Try doing serial dilutions of the antibody against the antigen to test 
this.  

Perhaps less likely, there are some situations where allergy is not IgE 
dependant.  C5a, IL-3 and hypoosmolality can activate mast cells in some 
circumstances. 

Hope this helps,

Regards,
C. Allen Black, Ph.D.
University of Pittsburgh



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