Growth characteristics of free tumor cells transferred serially in the peritoneal fluid of the mouse.

Abstract

1. Requisite numbers of Sarcoma 37 or malignant lymphoma cells, obtained either from subcutaneous implants or by serial transfers in the peritoneal fluid, were inoculated intraperitoneally into several groups of CFW or dba mice. The rate and the amount of cell growth in each mouse were studied quantitatively. Specimens of peritoneal fluid were withdrawn repeatedly, at various time intervals, from the same mouse, for total and differential cell counts (number of tumor cells per 0.1 cubic centimeter, percentage of mitoses, of necrotic elements, and of leukocytes). The results from each group of mice were tabulated and plotted in graphs. 2. The growth in the peritoneal fluid of tumor cells from both strains presented the following essential features: ( a ) Intraperitoneally inoculated tumor cells multiplied in the peritoneal fluid independently of peritoneal implants, i.e., before and sometimes without the growth of tumor tissue in the peritoneum; thus, the multiplication of free tumor cells appeared to be a primary phenomenon. ( b ) Free tumor cells multiplied continuously in the peritoneal fluid in serial intraperitoneal transfer of this fluid from mouse to mouse, thus appearing as a culture of the inoculated tumor strain. ( c ) Serial intraperitoneal transfers increased the growth potential of tumor cells in the peritoneal fluid and in the subcutaneous tissue. ( d ) For the cells of the same source, i.e., of the same growth potency, the amount and the rate of growth were proportionate to the number of inoculated cells. It is suggested that these phenomena are probably not specific for the tumor strains used in our work, but may be reproduced with other tumor strains. 3. The growth of free malignant lymphoma cells in the peritoneal fluid, as compared with the growth of S-37 under the same conditions of experiment, presented the following special features: ( a ) The growth cycle of lymphoma cells in the peritoneal fluid lacked the final stage of inactivity and of partial regression which terminated the growth cycle of S-37 free cells. ( b ) The percentage of lymphoma cells in the cellular content of the peritoneal fluid increased in each mouse steadily from the end of the lag period until the death of the animal. This phenomenon contrasts sharply with the intense leukocytic reaction to S-37 cell multiplication in CFW mice. These differences in growth characteristics of free lymphoma cells in the peritoneal fluid would appear to be attributable to the essential difference between the “strain specific” quality of lymphoma cells for dba mice and the “foreign” nature of S-37 cells for CFW mice.