Electron Microscopic Studies of Rat Leukemia Induced with Mouse Leukemia Virus.

Abstract

Electron microscopy of sections of bone marrow, spleen, lymph nodes and mediastinal tumors from rats with leukemia induced by Gross mouse leukemia virus revealed the presence of 2 types of particles. Virus particles (990 A) with an electron-dense center, surrounded by one membrane and vesicular particles (840 A) with an electron-lucent center, surrounded by one or two membranes. These particles were found in megakaryocytes of bone marrow and spleen, cytoplasmic inclusions in the cytoplasm of cells of lymph nodes and mediastinal tumors, and in intercellular spaces. Cylindrical structures were observed in megakaryocytes of spleen and bone marrow. These structures and vesicular particles may be a stage in the development of virus particles. No particles could be found in similar organs or tissues of normal rats.