Preservation of mammalian cells in a chemically defined medium and dimethylsulfoxide.

Three established mammalian cell lines (cat kidney, L, and HeLa cells), grown in suspension in a protein-free, chemically defined medium, were stored under liquid nitrogen in the defined medium fortified with 4 and 8 percent dimethylsulfoxide. After storage for 1 month the recovery viability was 86 percent, and cells showed normal growth upon reinoculation into the defined growth medium.