Radiation dose-independent inactivation of isologous mouse lymphoma cells by nonspecific resistance.

An X-ray dose-independent inactivation process for LSA mouse lymphoma cells was quantitatively assessed. The process reduces survival of tumor cells at all levels of cell X-ray dosage and survivorship. In these experiments, the dose-independent inactivation constant was quantitatively determined and essentially reduced the tumor cell population at risk. This resistance appears to correspond to a non specific process which could neither be actively produced nor passively transferred, but which was sensitive to and reduced by whole-body irradiation. It appears to be more efficient against very small numbers of cells (one), either in a small challenge inoculum of cells or as the surviving cell in a larger number of radiation-killed lymphoma cells.