What is considered a successful viability range for a frozen cell line like EBV?
Preservation of EBV transformed lymphocytes.
We typically achieve 85% viability (number of cells with intact membranes divided by total number of cells post thaw) and a yield of 78% (number of viable cells post thaw/number of viable cells pre-freeze) for lymphocytes transformed with SV40. These results are achieved with a 10% DMSO solution and a finely tuned controlled rate freezing protocol with an average cooling rate of 1 C/min. If you are getting considerably lower values, you may want to debug your protocol. We go through the debugging process in detail in our preservation short course.
We do not have direct experience with EBV transformed lymphocytes but
we have a service project in this area scheduled for Spring 2010.
Please check back in Summer 2010 for a published protocol.
Note #1: Other methods of immortalizing lymphocytes (transposons, etc) may influence freezing behavior.
Note: #2: Primary lymphocytes (lymphocytes that have not been immortalized) have a distinctly different freezing response. Furthermore, highly purified lymphocyte populations will respond differently to freezing than mixed lymphocyte populations.
