Development of Myeloid (Chloro-) Leukemia in Thymectomized C3H Mice Following Inoculation of Lymphatic Leukemia Virus. ∗

Abstract

Summary

1. Thirty-nine C3H mice were thymectomized at 4 to 6 weeks of age and inoculated a few days later with passage A leukemic filtrates. None developed leukemia, although observed until they were 15 months old. Of 41 non-thymectomized adult control mice injected simultaneously with the same filtrates, 63% developed leukemia at 8.7 months average age. 2. Of 60 C3H mice inoculated with passage A leukemic virus at average age of 3 days and thymectomized a month later, 26 (43%) developed leukemia at 10 months average age. Among leukemic mice in this group. 8 developed myelogenous (chloro) leukemia. Of 85 litter-mate controls injected simultaneously with the same filtrates. but not thymectomized, 93% developed lymphatic leukemia at 3.6 months average age. 3. Myelogenous leukemia developing in some virus-injected and subsequently thymectomized mice could be readily transplanted to mice of the same strain, retaining its myelogenous form or changing to lymphoid. 4. Susceptibility of thymectomized mice to the leukemogenic action of passage A virus could be restored by subcutaneous implantation of thymuses from young normal C3H mice. Of 20 C3H mice injected with the leukemic virus, then thymectomized, and which subsequently received subcutaneous implants of normal C3H thymuses, 18 developed leukemia (2 of these were myelogenous), as compared with 35 of 36 non-thymectomized controls that had received the same filtrates.