A Survival Curve for Mammalian Cells irradiated in vivo

Abstract

HIGH density single-cell suspensions of transplantable mouse leukæmia cells have been prepared from the infiltrated livers of leukæmic CBA mice. The density of morphologically healthy malignant cells in a suspension was determined by counting by phase-contrast microscopy, and selected serial dilutions of the counted suspension were injected intraperitoneally into groups of isologous mice. From the leukæmia mortalities in the injected groups the mean number of leukæmia cells required to convey leukæmia to half a group of injected mice (the TD50) was calculated by the method of Reed and Muench¹. In six such bio-assays of suspensions from the livers of untreated leukæmic mice, TD50 values ranging from 0.7 to 3.0 (mean 2.0) were obtained.