Brenda,

Do a search in the archives, using the word "skim milk" and you'll get a procedure for using egg whites and skim milk to block endogenous biotin.  I use the Vector A/B block kit myself.  Using the homemade stuff would make me too hungry.

Teri Johnson
Manager Histology Core Facility
Stowers Institute for Medical Research
1000 E. 50th St.
Kansas City, Missouri  64110
tjj@stowers-institute.org


-----Original Message-----
From: Greg Dobbin [mailto:dobbin@Upei.CA]
Sent: Friday, February 01, 2002 8:11 AM
To: Brenda D Begg
Cc: histonet@pathology.swmed.edu
Subject: Re: Biotin block (was IHC for cryptosporidium)


Hi Brenda,
A biotin block is not the same as a normal serum block. The normal 
serum blocks nonspecific binding sites in the tissue that may bind 
the secondary antibodies (for reasons other than specific Ab-Ag 
interaction). If you do not block endogenous biotin, the streptavidin 
will bind, not only to the biotinylated secondary Ab, but to the 
endogenous biotin as well. I use a biotin blocking system from 
DAKO, but there are "homemade" ways to accomplish this; 
however, others are better equipped to address that issue.  
Cheers!
Greg

Date sent:      	Fri, 01 Feb 2002 13:49:05 +0000
From:           	Brenda D Begg 
Subject:        	Biotin block
To:             	histonet@pathology.swmed.edu

> 
> Hi Guys
> Thanks for your reply Greg D. Is a biotin block the same as a protein block ie. could I use 0.5% casein.Or can you give me an example of a biotin block I could use. 
> 
> Brenda B 
> 
> 


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Greg Dobbin
Pathology Lab
Atlantic Veterinary College, U.P.E.I.
550 University Ave.
Charlottetown, P.E.I.
Canada,  C1A 4P3
Phone: (902)566-0744
Fax: (902)566-0851