Please let the list know what you learn about antibody storage. Wishing to
avoid freeze-induce protein aggregation, I stored at 4 degrees C in azide
(no glycerol) portions of some FITC and tetramethyl rhodamine conjugates
(of mouse and rat monoclonal antibodies) we made, sometimes with
protease-free BSA (Sigma). In all cases the majority of the initial
activity was gone within 6 months to one year. I believe that at -20
degrees, the protein is actually concentrated in liquid water and high salt
excluded by ice crystals. I don't know whether the 50% glycerol avoids
this, but I haven't tried it. Of course, the worst thing is to put any
protein solution in a -20 degree SELF-DEFROSTING freezer (home type) since
this cycles up and down in temperature, recrystallizing the water and
neatly excluding all the protein, thereby denaturing much of it. If your
lab freezer always has a build-up of frost, you're safe. I now store my
conjugates at -80; rapid freezing (e.g. in liquid nitrogen) is best (to
minimize separation of solute from solvent) but I rarely bother.
On a related topic, can someone give actual before-and-after-freezing
results on fluorescence intensity from phycoerythrin-conjugates?
I've frozen most of mine at -80 degrees to keep them (in your words)
"for use in the next millenium" and they work, but I don't know
how much loss in intensity I'm taking, or whether it varies from
one conjugate to another. I do of course try to freeze only once
for PE, whereas I don't worry about several freezes for FITC or
TRITC (actually, we use succinimidyl ester, TRSE).
In message Wed, 21 Feb 1996 09:22:16 -0500 (EST),
Calman Prussin <Calman_Prussin@d10.niaid.pc.niaid.nih.gov> writes:
> I have a number of conjugated antibodies in large amounts that I would
> like to preserve for use in the next millenium. Any suggestions on how
> to do this? I have heard of adding glycerol at 50% v/v with storage at
> -20 C. Does anyone have any experience with this or know a reference?
> Thanks
> Calman Prussin
>
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