THE INITIAL GROWTH-RATE OF KREBS-II ASCITES CELL TUMORS IN MICE IS SLOWED DOWN BY THE INCLUSION OF PHYTOHEMAGGLUTININ IN THE DIET

Twelve days after injection the total number of Krebs II cells in asci tes tumours in mice fed on a diet containing kidney bean lectin phytoh aemagglutinin (PHA) was about 60% of that in mice fed on a control die t (lactalbumin-LA). The growth characteristics of the tumour cells in PHA- and LA-fed mice were quite different; in mice on the PHA diet the growth rate was initially very slow, but increased greatly between da ys 5-8 and 9-12, while in mice fed on LA the rate increased progressiv ely during the observation period. It is thus apparent that inclusion of PHA in the diet results in an initial low rate of proliferation of the tumour cells. In LA-fed mice the volume of ascitic fluid measured 7 days after i.p. injection of Krebs II cells was about threefold high er than that in mice maintained on the PHA diet. The results suggest a correlation between exposure to the PHA diet and a rapid event occurr ing in the host which leads to a transient reduction in cell growth an d slows down the production of ascites tumours.