Effects of Ehrlich ascites antisera on the biochemical activities of Ehrlich ascites carcinoma cells in vitro.

Anl i-tumor sera are now being extensively used in investigations of the activities of neoplasms (e.g. 4-7, 9-13, 15). I t is already known (7), concerning their effects on the biochemical activities of tumors, that Ehrlich ascites carcinoma cells, treated with their antisera in the presence of comp]ement, lose their capacity to respire in the presence of glucose but not in the presence of succinate. Moreover, antisera prepared against ribonucleoprotein fractions isolated from cells of the Ehrlich ascites carcinoma arc capable of inhibiting the utilization of glycine-~-C 14 of these cells in vitro (5). Loss of cell protein and ribonucleic acid also occurs. In view of the importance of understanding the biochemical consequences of the addition of antitumor sera to tumor cell suspensions, we have investigated the effects of such additions on both the uptake (transport) of glycine into the tumor and its incorporation into tumor proteins, as well as on the respiratory and glycolytic activities of the cells. We have also studied these effects as a function of time, from the moment of addition of the antisera to the tumor cells and before microscopic visible changes in the cells occur. Our objective has been to ascertain in what manner anti-tumor sera affect the metabolic activities of susceptible tumor cells.