We are having trouble with our VCC going down to half as we are moving adherent CHO cells to suspension. Any ideas on how media could help with the transition. We are using an off the shelf CHO media right now.

Answer

Going from adherent culture to suspension can be tricky, especially when going from a protein containing to a chemically defined (CD) formulation. The following procedure should work for you. Grow your cells in the medium that they have been adapted to and collect the supernatant(call it CM for conditioned medium) 2 to 3 days after plating. The cells should be in log phase growth at this time. Plate the cells as you normally do but now the medium should be a 50:50 mixture of CD (assuming this is the medium you want to adapt the cells to. If not add whatever medium you want to use for suspension culture and for this protocol we will still call it CD) and CM. When the cells are growing well (in phase growth which should be 3-4 days), collect the CM and mix it 50:50 with the fresh CD. Continue this until the suspension cells are growing well. If in the beginning they slow down, go back to saved CM from the previous plating. The CM contains lots of growth and viability enhancing factors that the cells produce for their own survival. Once the cells are growing well as suspension culures, you can use only your selected CD medium.