Immunopathology of NZB/BL mice. VI. Virus separable from spleen and pathogenic for Swiss mice

Hemolytic disease characterized by slight anemia, reticulocytosis, hemosiderosis, extramedullary hematopoiesis, and positive indirect antiglobulin (Coombs') tests and renal disease with proteinuria, hypoalbuminemia, and glomerular lesions were produced in Swiss mice by neonatal intraperitoneal inoculation of cell-free filtrates prepared from the spleens of old NZB/Bl mice. Lymphoid cell and plasma cell hyperplasia as well as hypergammaglobulinemia occurred in some of these inoculated mice. Type "C" murine oncogenic virus-like particles, indistinguishable from those previously described (1), were shown by electron microscopic study to be present in distinctive locations, notably in the basal foldings of convoluted tubules in the kidneys of a newborn NZB/Bl mouse, old NZB/Bl mice, a CBA x NZB F(1) hybrid mouse, and a Swiss mouse inoculated with NZB/Bl spleen cell-free filtrate. These observations point to two (perhaps related) circumstances which may be requisites for the pathogenic action of this newly discovered virus within and outside the strain NZB: infection of newborn, or infant, mice; persistent, possibly tolerant, infection of adult mice.

Immunopathology of NZB/BL mice. V. Viruslike (filtrable) agent separable from lymphoma cells and identifiable by electron microscopy

A filtrable agent separable from transplantable malignant lymphomas of NZB/Bl mice was capable, upon inoculation into preweanling NZB/Bl mice, of inducing lymphoid cell hyperplasia, hypergammaglobulinemia, proteinuria, hypoalbuminemia, and pathological changes (focal membranous glomerulonephritis) of kidneys-renal functional and structural changes qualitatively similar to those of spontaneous occurrence in older NZB/Bl mice. Viruslike particles with close resemblance to the typical "C" type murine oncogenic virus particles were identified by means of electron microscopy in NZB/Bl mouse tissues and cells, including malignant lymphoma cells, benign lymphoid cells of thymus and spleen, epithelial cells of renal tubules, and extracellular sites. The relevance of these observations, the first of their kind dealing with NZB/Bl mice, is discussed in relation to the several immunopathological disorders which characterize this strain of mice.