Preservation at Subzero Temperatures of Mouse Fibroblasts (Strain L) and Human Epithelial Cells (Strain HeLa).

Abstract

Mouse fibroblasts of strain L (Earle) and human epithelial cells of strain HeLa (Gey) were preserved successfully at -60[degree] to -70[degree]C for 6 and 7 months, respectively. Glycerol in the suspending liquid greatly increased the percentage of surviving cells. Solutions of glycerol (5% for strain L and 20% or 30% for strain HeLa) in a solution for maintenance of animal cells (MS), in balanced salt solution, or in serum (horse serum for strain L cells, adult human serum for strain HeLa cells), were of approximately equal value for the periods of preservation studied. The cells survived storage poorly at -60[degree] to -70[degree]C when suspended in undiluted serum or in 5% dextrose in water. Strain L cells were preserved in slightly greater numbers after freezing over a period of 1-1.5 hours than after freezing in 3-5 minutes; strain HeLa cells survived both freezing procedures equally well. Better preservation of both cell types resulted from storage at -60[degree] to -70[degree]C than at -20[degree]C, and from thawing in 1-2 rrin., rather than in 30-60 minutes. The value of low temperature preservation for handling and maintenance of strain L and strain HeLa cells and for preservation of strain stability is discussed.