Storing frozen cells in -80C instead of liquid nitrogen - (Sep/20/2011 )

Hi,

I usually freeze my cells in -80 degrees and then transfer them to a liquid nitrogen tank a day later for future storage.

However, I left one of my cell lines in the -80 degrees accidentally for a month so I was just wondering if they will be OK. How do I know if they are not OK?

Thanks a lot!

Most (non-primary) cell lines will be OK for a month at -80, primary cell lines might have some issues though. The only real way to check is to thaw them out and see if they still grow OK.

It is a leukemic cell line (HL60 cells). The cells seem to be growing fine, but I am worried that maybe there will be some genotypic changes (my research is in genomics so I would be concerned about sensitive changes) Thanks!

In that case, no-one will have looked and the only way to tell will be to compare the expression of many genes (perhaps microarray) between cells you know have been treated OK and these ones.

Lab based evolution of cell lines is a big problem...

I would say you have a worse chance of generating genomic changes by continuous passaging than you do by one month storage at -80 degrees.

Some of the people in my department use -80 to store their cells. I have not heard any serious problems with them. But, since your work depends a lot on genotypic stability, unless, as bob 1 said, you do some real experiments to address this problem, I don't think one will be able to tell the genomic changes occurred.

The ideal thing to do is to keep the cells in -80 for a day or two soon after freezing down protocol (in a Nalgene cryofreezer or something of that kind) and then transfer them into liquid nitrogen

It is only good for short-term storage.  I believe 6 months are the shelf-life, and longer than that is at your own risk.

We unfortunately had to do 'the great -80C experiment' one year.  A -140C freezer went down and the only space available was in a -80C freezer. The cells where mostly human PBMCs and lymphs. After a few months at -80C, the viability of the cells when thawed was miserable. Usually  20-30%V.