BSA quality RE: [Histonet] blocking solution

[Gayle Callis]

Dear L  "the novice at immunolabeling" and asking about BSA

Question:  Did you have a problem with your staining after using a normal 
serum block?  If so, let us know what happened - we can always help with 
specifics too.

What Cynthia discussed about BSA is important.  Jackson ImmunoResearch 
catalog/website discusses the caveats about using BSA with large animal 
species.  If you need to use BSA, it must be of highest molecular biology 
quality or buy Jackson's immunoglobulin and protease free BSA. If you 
purchase BSA from Sigma, look for the same quality as Jacksons. If you look 
at  Jackson data/specification sheets  for their antibodies, the protein 
carrier is their BSA.

We choose to use normal serum blocking exclusively, as Cynthia 
discussed,  for our animal work, even other than mouse.  BSA is reserved 
for special types of staining,i.e. lectin where serums containing 
carbohydrate or sugar residues can bind to lectins.

For clinical i.e. human work, many of the blocks contain BSA and work fine, 
sold ready to use - these have not worked well in my hands for my murine 
IHC or IFA work. There are other serum-free blocks available some with 
casein to try. Some good reading can be found for free, DAKO Handbook of 
Immunochemical Staining, 3rd edition, you can download the pdf and print it 
off.  There are also some good, inexpensive books to help you.

Introduction to Immunocytochemistry, 3rd Edition Plak and van Noorden 
(ISBN#1-85996-208-4) Amazon.com

Immunochemistry 2, a practical approch.  Ed. Johnstone AP, and Turner 
MW  (ISBN# 0 19 963609 5)

Gayle Callis HTL, HT, MT(ASCP)
Research Histopathology Supervisor
Veterinary Molecular Biology
Montana State University
Bozeman MT 59717


At 05:16 PM 5/16/2006, you wrote:
>In my hands BSA often causes more problems than it solves. One needs to
>be careful of the grade used, it is very 'sticky' and I have had more
>non-specific background staining using BSA than with just about anything
>else. We previously have studied mostly rodent brain and eye which I
>have found to have very little background problems. Also if you are
>using and goat primary you can get some cross-reactivity with BSA and
>some anti-goat IgG's depending on purity, specificity etc.
>
>So to get to the heart of the matter I only block for endogenous
>peroxidase unless I have a problem and then I will block with normal
>serum of the host species of the secondary. I am becoming a minimalist!
>
>c
>
>Cynthia Favara
>NIAID/NIH/RML/LPVD
>903 South 4th Street
>Hamilton, MT 59840
>406-363-9317