AUTOIMMUNE DISEASE IN NZB/BL MICE : III. INDUCTION OF MEMBRANOUS GLOMERULONEPHRITIS IN YOUNG MICE BY THE TRANSPLANTATION OF SPLEEN CELLS FROM OLD MICE

The transplantation of spleen cells from old NZB/Bl mice with renal disease induced both the structural and the functional changes of membranous glomerulonephritis in young NZB/Bl mice within a few weeks and well in advance of its usual spontaneous occurrence. The development of hypergammaglobulinemia and lymphoid cell hyperplasia in the young mice indicated that immunologically competent cells, derived from either the transplant or the recipient, proliferated during this process. These experiments, together with other findings, provide further support for the view that membranous glomerulonephritis in NZB/Bl mice is produced by immunological, and probably autoimmune, mechanisms and that the renal disease is apparently almost wholly unrelated to the hemolytic process

AUTOIMMUNE DISEASE IN NZB/BL MICE : I. PATHOLOGY AND PATHOGENESIS OF A MODEL SYSTEM OF SPONTANEOUS GLOMERULONEPHRITIS

This study, based upon 528 laboratory examinations and 16 complete autopsies of NZB/Bl mice, deals with autoimmune manifestations (as shown by hypergammaglobulinemia, Coombs positive hemolytic anemia, and the occasional presence of lupus- and rheumatoid-like factors) and mainly with the pathology and the pathogenesis of glomerulonephritis in these mice, a model system of membranous glomerulonephritis with spontaneous and insidious onset, progression through chronic stages, and almost certainly induced by immunological, and autoimmune, mechanisms. The earliest and lasting histological change was hyaline thickening of the capillary walls and adjacent intercapillary regions of the glomerular tufts, corresponding in location to polysaccharide-rich capillary basement membrane and mesangial materials. Distributed focally and diffusely in the glomerular tuft and eventually sparing no glomerulus, hyaline, granular, and fibrillar ("spongy fiber") materials produced narrowing of capillary lumens by concentric or eccentric encroachment upon them. In the later stages hyaline lobulation and sclerosis of the glomerular tufts occurred. Thus the lesions corresponded to those seen in human focal and diffuse membranous, chronic lobular, and lastly (intracapillary) sclerosing glomerulonephritis. In all instances of glomerulonephritis the glomerular tufts contained selective localizations of mouse immunoglobulins corresponding in distribution to that of the hyaline and (PAS-positive) polysaccharide-rich materials in the focal and diffuse membranous and lobular lesions and in amounts increasing with the severity of glomerular disease. The mouse immunoglobulins were extracted from frozen sections of glomerulonephritic kidneys and were then capable of recombination with glomerular tufts in sections of autologous or isologous glomerulonephritic kidneys from which in vivo localized immunoglobulins had been extracted. The pattern of recombination with glomerular tufts was similar to that of in invo localized immunoglobulins. The extracted immunoglobulins did not show affinity for mouse red cells (in the indirect Coombs test) nor for autologous or isologous cell nuclei (in the immunofluorescence test). The serum of mice with severe glomerulonephritis contained immunoglobulins with in vitro affinity for extracted autologous or isologous glomerular tufts. Thus circulating as well as localized antibodies were demonstrated. The immunogenic materials (autoantigens) may have been formed in the glomerular tufts or accumulated in them from some other source, such as the circulating plasma; however they corresponded in location to polysaccharide-rich capillary basement membrane and mesangial materials. The spleen was identified at the cellular level as the main site of formation of autoantibodies to red cells, as well as the main site of red cell destruction. Some evidence was brought forth suggesting that these autoantibodies were "heavy" or γM-globulins. More studies are in progress

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

FURTHER IMPLICATION OF MURINE LEUKEMIA-LIKE VIRUS IN THE DISORDERS OF NZB MICE

Further evidence implicating murine leukemia-like virus in the disorders of NZB mice was afforded by a study of antigens associated with murine leukemia virus (MuLV). MuLV group antigens were prevalent in extracts of spleen, kidney, and, to a lesser extent, thymus throughout a substantial portion of the life span of NZB mice as well as in extracts of lymphomas and sarcomas indigenous to the strain. G (Gross) soluble antigen, type-specific antigen, was first detected in plasma of untreated NZB mice at 3 months of age. G soluble antigen production increased thereafter in line with age, with 50% of reactions becoming positive at 5.3 months and 100% at 7 to 9 months. From months 3 to 9, the time-response curve for positive conversion of direct antiglobulin (Coombs) tests in untreated NZB mice corresponded closely to that for G soluble antigen production. Beyond the 9th month, G soluble antigen underwent elimination from the plasma of NZB mice, with positive reactions reduced to 50% at 13.3 months and to 0% at 18 months. G natural antibody was first detected in the serum of NZB mice at about 10 months of age and increased thereafter in line with age. The curves for G antibody production and G soluble antigen elimination bore a reciprocal relation to each other with crossover at 50% response occurring at 13.3 months. Significant proteinuria, a functional manifestation of membranous glomerulonephritis, became increasingly prevalent in female NZB mice as G soluble antigen was eliminated from plasma. Cumulative mortality of female NZB mice, mainly attributable to renal glomerular disease, increased in phase with G antibody production. MuLV group antigens were identified in the glomerular lesions by the immunofluorescence method. Positive conversion of direct antiglobulin tests was significantly delayed by vaccinating baby NZB mice with formaldehyde-inactivated cell-free filtrates of older NZB mouse spleens. The plasmas of vaccinated NZB mice with negative direct antiglobulin reactions at 4 to 7 months were likewise negative when tested for G soluble antigen. The 50% response time for G antibody production in the vaccinated NZB mice occurred at 7.3 months, that is, 6 months earlier than in untreated NZB mice. The collective findings implicate murine leukemia-like virus in the etiology of autoimmune hemolytic disease and membranous glomerulonephritis, as well as malignant lymphoma, of NZB mice and suggest that virus-specified cell-surface and soluble antigen is a factor in the immunopathogenesis of the renal disease and possibly also the autoimmune hemolytic disease