I have a limited volume of a polyclonal antibody and I look to use it as efficiently as possible. I have aliquoted the antibody and stored the aliquots at -80°C. Whenever I need to perform an immunoassay, I take an aliquot and still have some remnant after the experiment is done. I store this remnant at 4°C for later use. I have read that it is best for samples (not antibodies) to be flash frozen with liquid nitrogen for later re-use and so that they do not denature.
Which is best, to store the antibodies at 4°C or to flash freeze them and place them, once again, at -80°C?
Thanks so much in advance.
Hi Eduardo
It does depend on the Antibody however having over 25 years experience I have found that once defrosted a vial of Ab held at 4C retains activity for months and often years. Often when I store aliquot batches of Ab at -20C I add small concentration of sodium azide to prevent bacterial growth. What you don't want to do is freeze, thaw and refreeze - this will likely effect Ab structure / activity over time
Hi, Eduardo.
Stored antibody at 4C is not a good idea, and Re-using the remaining ab by freezing and thawing is neither. You will waste more money and even seriously time. When you have new ab, dilute 2x in PBS+2mg BSA/ml as a carrier protein and to prevent loss of ab on the walls of tube in Lamina flow for cell culture. Make 5 ul aliquots of 2x stock solution, store at -70C until use. At use, dilute again at appropriate dilution to adjust your final concentration. After using the diluted sol, it is the best to throw it away to save money and time. Once opened in air, ab have many possibilities to be contaminated.
Regards.
Hi, it depends on the antibody. We store GARPO in aliquots at - 80C. After thawing a 20 microliter portion we keep the rest of unused GARPO at 4C for several days and it works fine. My suggestion is - just try whether your antibody is stable for some time at 4C.
Hi Eduardo
It does depend on the Antibody however having over 25 years experience I have found that once defrosted a vial of Ab held at 4C retains activity for months and often years. Often when I store aliquot batches of Ab at -20C I add small concentration of sodium azide to prevent bacterial growth. What you don't want to do is freeze, thaw and refreeze - this will likely effect Ab structure / activity over time
Thank you all for your input to this question. I will follow up and do Western Blots using a 4°C aliquot and a -80°C aliquot to compare and contrast my results. Once again, thank you very much for taking time to answer my question. May your research be fruitful!
Antibody in serum remains stable at 4 oC month to years provided you have kept it properly in conventional fridge and not in frost free fridge. You may add very small amount of either sodium azde or thimerosal to prevent bacterial growth. Addition of poly-ol and BSA further stabilises antibody. The most convenient way is to preserve antibody activity at 4 oC by mixing antiserum with equal volume of saturated ammonium sulphate solution.
With best wishes
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