Long-Term In Vitro Cultivation of Some Mouse Ascites Tumors: Ehrlich Ascites Carcinoma

Ehrlich ascites tumor cells have been grown for more than a year in tissue culture. Changes in morphology, cell size, and chromosome number occurred with variations in the media used. Cells grown on fetal calf serum were predominantly small and spindle-shaped with a chromosome number ranging around a median of 65. Cells grown on ascitic fluid medium and later cloned were frequently multinucleate, ameboid in shape, larger, and often contained a higher number of chromosomes. Tissue-culture strains of cells, when injected at a level of 105 cells or higher, produced characteristic ascites tumors in mice even after 36 transfers and 9 months' growth in vitro. Doses of 103 cells in general produced very few tumors (less than 20%) and apparently induced a high degree of resistance against a subsequent lethal dose of 105 tissue-culture strain cells. Protection against the mouse-grown Ehrlich ascites cells was less marked, but a significant increase in survival time occurred.