IgM purification?

scott gens gens at biodec
Thu Jul 21 20:13:23 EST 1994

I have a 200 uL of a monoclonal mouse IgM antibody in ascites fluid that I 
would like to purify. This is all I have so I need to get it right on the
first try. 

Protein A supposedly binds to IgG and IgM, but most catalogs present 
tables which state that their Protein A columns do not bind mouse IgM. Is 
mouse an exception, then? Why the apparent contradiction?

BioRad's catalog seems to suggest that their Protein A does bind mouse IgM
but they insinuate that this only happens when their 'MAPS buffer' is used.
Then they also state that 'approximately 50% of all mouse IgMs bind to 
protein A'. So does this mean that basically I only have a 50% chance of
purifying my IgM using their system, and if so, why should I want to gamble
on my IgM being in the lucky 50%, especially when none of the other catalogs
I have make similar claims?

Seems like my other option is to take the opposite approach and use a
chromatography column that binds the stuff I DON't want and allows my 
IgM to run through. It appears that a Carboxymethyl and Cibracon blue dye
gel or its equivalent might be suitable in this regard.

Catalogs seem to be geared towards IgG though, will this method work for 
IgM, and can anyone tell me from experience whether losses will be 
excessive for IgM purified this way? Loss of more than 10-15% of my small 
amount of starting material is not going to be acceptable.

Thanks in advance

Scott Gens
gens at biodec.wustl.edu

More information about the Immuno mailing list