I would like to freeze MDSCs obtained after a FACS sorting. Has anybody a specific protocol for doing that? Or should I use just fetal bovin serum with DMSO?
Hi Caroline, as far as I know, there are no specific protocols for freezing specific cells.
To keep cells viable during the freezing process, you have to include an agent (DMSO) that depresses the formation of ice crystals that can puncture your cells and have a lot of proteins (FBS) that protect the cells from localized ice crystals.
When you freeze a protein/cell solution, the first things to freeze and form crystals is H2O. The solutes (proteins, cells and salts) are then concentrated because they do not fit into the crystal H2O lattice. The concentrated solution of proteins, cells and salts are the last ones to freeze. This will kill cells because ice crystals and high salt conc. compromise cell integrity.
DMSO prevents the formation of ice crystals and allows the entire solution to freeze equally without localized H2O ice crystals and high salt conc.