An animal model for intractable chronic lymphocytic leukemia

Lymphomas developed in mice treated with X-irradiation. The radiosensitivity of cells of the lymphomas had a bimodal frequency distribution. The cells of 11 lymphomas had approximately the same radiosensitivity as normal murine lymphocytes; 6 lymphomas were highly radioresistant. Radioresistant and radiosensitive lymphomas were analogous to intractable chronic lymphocytic leukemia (CLL) and to responsive CLL in humans. The radioresistant lymphomas can be used to study the effect of therapeutic agents on the animal model for intractable CLL both in vitro and in vivo.