Studies on Leukemia in The C58 Strain of Mice Part 2. Isologous transmission of leukemia by cell-free extracts from leukemic tissue of mice

Isologous inoculations of cell-free extracts from the lymphatic leukemia in the C58 mice were performed using new born and suckling mice.1. Among the 92 inoculated mice, 31 had died of unknown infectious disease 1 or 2 months after the inoculation. Another 61 survived mice were observed for the development of leukemia thereafter.Forty three of them (70.5%) developed leukemia after the latent periods varing from 6 to 16 months. During the period of 6 to 10 month, 16 mice developed leukemia (37.2% of all leukemias developed). This was higher in incidence comparing with the incidence of leukemia occnrred (13.1%) in the control group within the same period. These fact indicates the accelaration of leukemia development by the isologous inoculation of the leukemic filtrate.2. Five of the inoculated mice (8.2%) developed myelogenous leukemia which had not been observed in the spontaneous case. Possibility of the transformation of leukemic type from lymphatic to myelogenous by the inoculation of leukemic filtrate was discussed in this paper, although its exact mechanism is not clear as yet.3. Cytological studies of myelogenous leukemia were performed. Peripheral blood, myelogram and impressed preparations of lymph node and spleen showed numerous appearance of myeloblasts and immature myeloid cells. In May-Giemsa stained preparations, myeloblast showed broad basophilic cytoplasm and eccentrically located nucleus with fine chromatin net work and clearly defined nucleoles. Nuclear indentation which was one of the characteristics of lymphoblast was not seen in myeloblast. Phase contrast microscopy of myeloblast was also lacking of nuclear indentation and showed centrically located large round nucleus. Mitochondrias were abundant and scattered throughout the cytoplasm. In electron microscopy, myeloblast had many well developed endoplasmic reticulums and small spherical mitochondrias in cytoplasm. Nucleus was round and nuclear substance was homogenous with a dense nucleole.4. Electron microscopic observations of lymph node and spleen of the myeloid leukemia mice revealed numerous extracellulary located virus particles. These virus particles were morphologically indistinguishable from that of lymphatic leukemia mice.