I just had a large order of flow antibodies accidentally stored over the weekend at -20 when they should have been at +4. Does anyone have any experience with this? Will they be okay or do I need to reorder?
Thanks!
It is very difficult to generalise. It sounds like you have quite a lot of antibodies. I don't think I would purchase everything again, but if you have a very complex and lengthy piece of work planned, with limited availability of samples, I can see why you might not want to risk it. Maybe there are some inexpensive controls cells you can try first?
On a technical level, it's not so much the freezing that is the issue it's more the rate of freezing, with slow freezing often being problematic. The reason is that the solvent (i.e. water) freezes first from the outside of the tube, leading to an extremely high buffer/salt concentration in the middle just before final freezing. Large volumes which freeze very slowly are therefore more prone to this issue. Ordinarily, I'd snap freeze on nitrogen or dry ice/ethanol before transferring to a freezer. However, if your aliquots are small I'd be fairly optimistic. Most antibodies are pretty robust in my experience.
Normally freeze and thaw is not recommended for antibodies. To maintain the structural integrity of antibody, cryoprotectant such as glycerol or ethylene glycol are added before storing at -20 degree C. From your content, it seems that it was accidentally kept for a week before you identified the mistake. Since, you received a large order of flow antibodies, I would suggest that you take a risk once to test one of the stored antibodies as per company manual protocol. Hope it will still work with your expectations, since aliquot of the working dilution of antibodies stored once at -20 degree work without having any significant deterioration in the antibody integrity. Go ahead and test with one of the antibodies stored at -20 degree. Good luck
I can tell you that freezing phycoerythrin (PE) conjugated reagents will significantly degrade their performance. I've done the experiment. :(
I agree with Nick Gee. If the samples are precious, and a control population is readily available, I would test each antibody individually to see how they stain.
Thank you all! I'm going to take the advice and test each one by one. Here's hoping I don't need to reorder.
Fiona
Dear fiona,
Freezing your antibodies at -20 would not much effect but it will certainly affect the fluorochrome. Because if you take note; antibodies for western blotting (primary/secondary) and ICC are recommended to be stored at -20 degrees.
But the freezing/thawing cycle may affect the fluorchrome confirmation or the binding chemistry.
So better you should run few control experiments and look if all the antibodies are woorking well, go ahead with these. Need not to re-purchase it.
Good Luck.
Test it, If the antibodies give you positive cells, it works or not and you will have to order. good luck
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