Hi I am immunoblotting looking for an antibody in human serum. Storing at -20C and -80C damages the antibody so I need to store the serum at 4C for the duration of use. I was wondering what the optimal conditions for extending the life of the serum at 4C are.
Are you sure that it´s a stability problem of your antibody and not of the antigen or anything else in your samples which can interfere with your assay? Antibodies circulate for month in the blood and I have never heard that freezing, especially at -80°C, will damage them.
To store serum long term at 4°C it´s important that you separate the serum fast from the clotted material. Protease inhibitors are a possibility.
I think that you would have the most unusual antibody in the world if it survived better at 4 deg C than at -20 or -80. If your antibody genuinely suffered damage during frozen storage the most likely reason by a mile would be accidental repeated freeze thawing. There are 2 main reasons for this ever happening.1) Purchase of domestic -20 freezers. These are often very cheap but unfortunately, unlike lab freezers, go through regular freeze-thaw cycles. No problem with a leg of lamb but disastrous for small biological samples! 2) Careless co-users of the freezer putting your samples outside while they rummage through its contents searching for their own. A single extra freeze -thaw rarely does too much damage to something robust like an antibody, but two or three can, and any more than that can easily destroy it.
Dear Carsten,
Since you are interested in an antibody in serum samples, you do not have to worry about stability when storing at 4C for 6-12 months in the presence of sodium azide (NaN3) at 0.02 (w/v)%. Please keep the samples away from direct sunlight because azide is light-sensitive.
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