Cryopreservation of cell line Paesun by a rapid cooling.

The purpose of the present study was to clarify the possibility of a rapid cryopreservation for cell line Paesun by cooling in the range of 30-40 °C/min to vapor phase of -120 ∼-140 °C before immersion into liquid phase of liquid nitrogen using 10% Me2 SO. After thawing, these cells were examined with assaying viability by trypan blue exclusion staining and survival by cloning in monolayer; the percentages of cell and colony recovery obtained in rapid cooling had a tendency to be lower than that by slow cooling of 1 °C/min but there were no significant differences between them. In addition, post-thaw cells were examined by assaying proliferation and susceptibility to virus lines; there were no significant differences between before and after cryopreservation. In conclusion, these findings indicate that Paesun can be successfully cryopreserved by the rapid cooling rate of 30 °C-40 °C/min.