Protocol for Freezing of Tissue Culture Cells with no Serum

1. Prepare freezing medium: 45% chilled medium, 45% conditioned (growth) medium, 10% DMSO
2. Harvest cells in log phase growth
3. Count cells be accepted method and centrifuge
4. Suspend the cells in the freezing medium at 5x10⁶ cells/mL
5. Aliquot the cells as appropriate
6. Freeze the cells in a rate controlled freezer or by placing them at -20^oC for approximately 3 hours and at -70^oC overnight
7. Store cells in liquid nitrogen