Calcium will block antibody binding but only if it is in mineral form
     and sitting on top of your antigen, for example if you are trying to
     demonstrate some of the scaffold glycoproteins in sections of
     undemineralised bone.  Ionic calcium, no problem, I used to used a Ca,
     Mg and Mn augmented buffer (lectin staining) for immuno and noticed no
     differences between it and the regular buffer.


______________________________ Reply Separator
_________________________________
Subject: Re: demineralized
Author:  HistoNet@Pathology.swmed.edu at Internet
Date:    11/24/98 1:28 PM


On Mon, 23 Nov 1998 NTT@shcc.org wrote:

> I'm posting this for a fellow researcher.  She would like to know if anyone
has
> a protocol for demineralizing adult rat trachea sections.  She thinks
>that the
> Ca++ maybe blocking the antibody.

  You don't usually think of the trachea as a "mineralized"
  organ. The cartilage rings might be a bit calcified as a
  result of some sort of experimentation. In this case any
  routine decalcifying procedure would shift the calcium
  easily. The idea that calcium ions inhibit antigen-antibody
  combination seems novel. There are plenty of ordinary
  reasons for failure of an immunohistochemical method!
  The first thing to do is make sure you have a control
  tissue known to contain the antigen, and stain this
  alongside the unknowns. There are other controls too,
  especially to eliminate false positive results.

 John A. Kiernan,
 Department of Anatomy & Cell Biology,
 The University of Western Ontario,
 LONDON,  Canada  N6A 5C1