For many of antibodies, freezing at -20C or -80C in small aliquots is the optimal storage condition. Aliquotting minimizes damage due to freezing and thawing, as well as contamination introduced by pipetting from a single vial multiple times. Aliquots are to be frozen and thawed once, with any remainder kept at 4C. Upon receiving the antibody, centrifuge at 10,000 x g for 20 seconds to pull down solution that is trapped in the threads of the vial, and transfer aliquots into low-protein-binding microcentrifuge tubes. The size of the aliquots will depend on how much one typically uses in an experiment. Aliquots should be no smaller than 10 µl; the smaller the aliquot, the more the stock concentration is affected by evaporation and adsorption of the antibody onto the surface of the storage vial.
In most cases, with the possible exception of ascites fluids which may contain proteases and should be frozen as soon as possible, storage at 4C upon receipt of the antibody is acceptable for one to two weeks, followed by freezing for long-term storage. Again, it is important to follow the recommendations on the datasheet.
Exceptions and other special conditions:
- Enzyme-conjugated antibodies, should not be frozen at all and should instead be kept at 4C. Freezing and thawing will reduce enzymatic activity in addition to affecting the antibody binding capacity.
- Conjugated antibodies, whether conjugated to fluorochromes, enzymes, or biotin, should be stored in dark vials or wrapped in foil. Exposure to light will compromise the activity of conjugates. Fluorescent conjugates in particular are susceptible to photo-bleaching and should be protected from light during all phases of an experiment.
- IgG3 isotype antibodies are unique in their tendency to form aggregates upon thawing and should always be stored at 4C.
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