Lynn,

You could also purchase a rabbit anti-rat antibody that is mouse absorbed from
Vector Labs.

Barb:)

"C.M. vander Loos" wrote:

> >Dear Friends,
> >
> >We are staining for anitbodies in nuede mice. They have been injected with
> >rat cells and we want to demonstrate the antibody in the rat cells. The
> >antibody is a rabbit anti-rat antibody. The problem is we get staining in
> >the tissue but everything is staining. The more worrysome problem is that
> >the Rabbit IgG negative control is also staining vibrantly positive even
> >more so than the antibody stained tissue. Does this mean that the rabbit
> >anti-rat antibody and the Rabbit IgG are cross reacting with the mouse
> >tissue? or something else?
> >
> >I block for Hydrogen peroxide, avidin and biotin and use a protein block
> >that is serum free. I can't figure this one out. Any hints would be most
> >appreciated!!!
> >
> >Thanks gang,
> >Lynn
>
> Although I am not really experienced with this type of tissue, I do know
> that mouse and rat immunoglobulins are very similar because of their close
> genetical relationship. As a result an anti-rat Ig antibody will cross
> react with mouse Ig for at least 50% (and the other way around). In your
> case it seems to me that the rabbit anti-rat antibody is reacting with
> mouse Ig in the tissue section.
> In order to prevent this you may try to mix the rabbit anti-rat antibody
> with 10-20% normal mouse serum, at least 30 min (at room temperature)
> before actual application to the tissue section. All rabbit anti-rat
> antibodies that tend to react with mouse Ig will be blocked then.
>
> Good luck,
>
> Chris van der Loos
> Amsterdam, The Netherlands