The Effect of Storage at Low Temperatures on the Mouse Strain Specificity of the 6C3HED Ascites Tumor Free

Cells of the 6C3HED ascites tumor, host specific for C3H mice, were preserved over dry ice at -78°C or over liquid nitrogen at -195°C with glycerol, dimethyl sulfoxide, or inositol as protective agents. After revival, a partial loss of host specificity was observed which varied with the protective agent employed but not significantly with preservation temperature. On subsequent passage, the host specificity was completely lost since 100 percent tumor takes were obtained in all strains during repeated serial transplantation. Loss of host specificity thus appeared to be a two-stage process. No change in chromosome number accompanied the loss of host specificity. Admixture with killed 6C3HED cells did not alter the host specificity of untreated 6C3HED cells. During the eighteen-month period of the experiments, the untreated 6C3HED cells gradually developed the ability to grow in AKR as well as C3H mice.