Does the virus titer degrade over time (like one year) at -80C? We have lentivirus and retrovirus, and had the feeling that the ones that are more than one year old are as not as good as new production, in terms of tranfection of cells in vitro or in vivo. But we never compare them quantitatively. Anyone has idea about it?
Never worked with lentiviruses or retroviruses. But with adenoviruses, baculoviruses and morbilliviruses titers do not significantly drop within a year.
Titers of even RNA viruses should not drop much in one year, if these have not been freeze-thawed several times!
Always store freshly amplified viruses in small aliquotes to avoid freeze-thaw cycles. Titrate one of the frozen tube immediately after freezing so that if you have any doubts, you can recheck the titers.
Freezing decreases lentifiral titer. If then properly cryopreserved they are expected to be stable for ling time. Anyway, expect titer to decrease by 5 to 10 times when using them after freezing.
Thanks Francesco, how about the duration of storage? Is there an established proper way to cryopreserve them?
Hi, in my lab we resuspend virus pellet in PBS only, and store microaliquots(for one usage only, to avoid freeze-thaw) at -80. Of course we titer it after having frozen the it. Coming back to your original question, we observed a drop of the titer of more or less 30% after one year. So, if long time has passed, I simply suggest to re-titer a sister aliquot before using it..you will know the real titer and, if it is acceptable, you can use it and you know how much you need!
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