[Histonet] Universal (protein) block for IHC

Walters, Katherine S katherine-walters <@t> uiowa.edu
Wed Apr 6 17:13:36 CDT 2005

I thought casein was just a fancy name for skim milk.  I use it
sometimes as an avidin block by making a 5% solution out of cheap dried


-----Original Message-----
From: histonet-bounces <@t> lists.utsouthwestern.edu
[mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of Kelly D
Sent: Wednesday, April 06, 2005 4:42 PM
To: Johnson, Teri
Cc: Histonet
Subject: Re: [Histonet] Universal (protein) block for IHC

Hi Teri,
I noticed a decrease in specific staining when I plugged it into my 
protocol. I made it myself and it was a big pain. Buy it! Try increasing

antibody concentration on a few slides and see what happens. I never use

a block with my secondary.

Good luck!

Johnson, Teri wrote:

>Has anybody converted to using a universal protein block (casein) for
>their immunohistochemistry protocols rather than using species specific
>normal sera?  For those who have made the conversion, did you have to
>make any changes to your methodology or did you just plug it in to your
>protocol and run?  Did you notice any difference in the staining
>intensity for known antibodies (stronger, weaker, no change)?  Are you
>also using it as a secondary antibody diluent or for washes?  Finally,
>are you using commercially available reagent or are you making your
>Thanks so much!
>Teri Johnson
>Managing Director Histology Facility
>Stowers Institute for Medical Research
>1000 E. 50th St.
>Kansas City, Missouri  64110
>tjj <@t> stowers-institute.org
>Histonet mailing list
>Histonet <@t> lists.utsouthwestern.edu

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