These cells have been growth-arrested by irradiation with 10,000 rads. The cells will begin to deteriorate in 7 to 10 days after plating and may no longer support the growth of other cells. We recommend that you do not keep the cells in culture for longer than 7 to 10 days.
Once the feeder cells have attached, the culture medium can be changed to accommodate the cells to be supported. It is recommended that the feeder cells be plated 24 hours before use at 4 to 5 X 106 cells per T75 flask in order to obtain a supportive monolayer for stem cell growth.