Electron microscopy of murine SJL-J disease.

Abstract

AbstractSJL/J inbred mice suffering from the neoplastic disease, very young apparently normal animals and mice bearing transplanted tumors were examined. Lymph nodes, spleens and occasionally thymuses, lungs and Peyer's patches were investigated under the electron microscope.It was found that very young (3‐week‐old) animals with slightly enlarged lymph nodes did not show any cellular or ultrastructural changes, although at the age of 8 weeks there was a certain proliferation of plasma cells. The onset of overt disease was marked by a massive proliferation of plasma cells with simultaneous paraproteinemia in mice sera. If the animal survived this stage of the disease, a regression followed. Although the tumors were still present, plasma cells were no longer abundant and a reticulum cell hyperplasia became evident. In this late period of the disease normal blood proteins or hypogammaglobulinemia were found. Mice with transplanted tumors developed reticulum cell sarcomas and the serum showed either normal proteines or hypogammaglobulinemia.Intracisternal particles were found repeatedly in the reticulum cells of the transplanted tumors and very occasionally in the spontaneous tumors, during the regression stage. These particles measured about 850 Å in diameter and were composed of a shell formed by two dense rings with a clear space in between, and a lighter central zone. The significance of these particles is discussed.