Antibody Storage

Antibody molecules that have compact and stable protein domains are resistant to a broad range of mildly denaturing conditions. This makes long-term storage relatively easy. Storage buffers seldom need to be supplemented with glycerol or other stabilizing compounds.

Most antibodies are stable for years when stored at -20°C in serum, tissue culture supernatant or ascitic fluid in which they are collected.

Note 1: With prolonged storage, many antibody solutions will generate an insoluble lipid component, which may look like microbial contamination. This is unlikely if sodium azide has been added.  The precipitate can be removed by centrifugation at 10,000 g.

Note 2: Some monoclonal antibodies and some components of serum or ascitic fluid are cryoproteins, sensitive to low-temperature storage where they precipitate. If cryoproteins are simply a contaminant, their precipitation provides a convenient method to remove them from the antibody solution by centrifugation at 10,000 g. However, if this treatment also removes the desired antibodies, storage at room temperature may be essential.

In general, working solutions of antibodies can be conveniently stored at 4°C where they are stable for at least 6 months.

The major problem commonly encountered in storing antibodies is contamination with bacteria or fungi. This can be prevented by filter-sterilization or the addition of sodium azide (0.02%).

Note 3: Sodium azide will block a number of biological assays and will interfere with some coupling methods. If necessary, sodium azide can be removed by dialysis or gel filtration. Care should be used with sodium azide as it is poisonous and blocks the cytochrome electron transport system.

Antibody solutions should not be frozen and thawed repeatedly, as this can lead to aggregation, causing a loss of activity. For this reason, it is best to aliquot samples prior to storage.

We recommend filter sterilization using a 0.45 micron filter and aseptic handling of all antibody solutions followed by aliquoting in convenient volumes and storage at -20°C.

Storage at -80°C is not generally considered harmful.