Light and electron microscope studies of organs and tissues of the New Zealand Black (NZB/BL) strain mice with lymphoid leukemia and autoimmune disease.

Light microscope studies of organs and tissues of 10to 12month-old leukemic NZB/BL strain mice revealed changes characteristic of lymphoid leukemia and autoimmune disease. Electron microscope studies of ultrathin sections of lymph nodes, spleen, liver, bone marrow, thymus gland, kidneys, and lungs of the same leukemic mice demonstrated immature and mature murine leukemia virus particles of the so-called Type C. These studies also revealed developmental stages of the leukemia Type C particles in various leukemic and nonleukemic cells and in parenchymatous cells of the liver and kidneys of the leukemic mice. Similar virus particles were also found in organs with changes characteristic of autoimmune disease, such as liver necrosis, lupus erythematosus lesions of the glomeruli, and fibrinoid changes in the blood vessels of the spleen of leukemic mice. The kidneys and liver of the examined mice appeared to contain a large number of virus particles regardless of infiltra tion by leukemic cells. Similar organs from 1to 3-month-old apparently normal mice oÃ-the NZB/BL strain were also found to contain murine leukemia Type C particles and budding of virus particles from plasma membrane of cells. On histologie examination, changes indicative of autoimmune disease were found in organs of 3-month-old but not in organs of 1-month-old mice.