agglutinated monoclonals

Roger Burger sl061 at CC.USU.EDU
Mon Oct 24 16:38:06 EST 1994

>Hi, netters
>we have a problem with purified (protein G) monoclonal antibodies. After
>thawing, they start to agglutinate. Is there any possibility to get them
>back in solution without destroying the acitivity? We did try:
>a) - sonication, no success,
>b) - increase salt concentration - no success
>c) - addition of 0.01% detergent - no success
>any suggestion is welcome.

>>From: muller.4 at (I. M=FCller)

This is a common problem with antibodies for all of us.  I do not freeze my
antibodies as they are extremely stable molecules and remain consistantly
active for years when stored at 4 degrees C.  I haved personally used
conjugated antibodies purchased 6 years ago in a flow cytometry assay and
the results compared nicely to a those obtained from the same clone
recently purchased.  During a workshop at the recent ISAC meeting in Lake
Placid, it was mentioned that antibodies as old as 15 years, stored in the
refrigerator, had been used with acceptable results.

Why Freeze?

 A protein chemist colleague of mine notes that freezing forces the
proteins into closer contact and allows for agglutination.  I try not to
freeze, but if I must I make dilute solutions and aliquot so I only need to
thaw once.  If I do need to use frozen antibodies I just centrifuge them to
remove the aggregates and accept the loss.

Hope this helps.


Roger A. Burger         E-mail: SL061 at
Research Immunologist
Center for Persons with Disabilities
Utah State University
Logan, UT  84322-6800
Voice: 801-7502042
=46AX:  801-7502044

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