The response of mouse lymphosarcoma cells to continuous gamma irradiation

Long-lasting survival of LS/BL tumor cells under continuous exposure in vivo to 60Co irradiation at an exposure rate of 10 cGy/h was observed. While LS/BL tumor cells tolerated the irradiation for more than 150 weeks, the number of hematopoietic stem cells decreased to less than 1% of control values within 7 days of irradiation. The liver colony method was used to develop sublines from nonirradiated and continuously (110 weeks) irradiated LS/BL cells for the analysis of karyotypes of the resulting clones of lymphosarcoma cells. The appearance of new structural abnormalities t(12:9) in one of the sublines tested correlated with its faster host killing when compared to the parent line.