Spontaneous glomerulonephritis in rabbits: role of a glomerular capillary antigen.

Spontaneous glomerulonephritis in rabbits: Role of a glomerular capillary antigen. Overt glomerulonephritis, detected by abnormal proteinuria, occurred in 3.3% of young (2.5 kg) male New Zealand White (NZW) rabbits. Histologically, mild to moderate mixed membranous and proliferative glomerulonephritis was observed. Glomerular deposits of IgG and C3 and electron microscopic findings were not typical of circulating immune complex accumulation, nor did they suggest antiglomerular basement membrane (GBM) antibody. Segmental and less intense glomerular deposits of IgG were found in up to 48% of nonproteinuric NZW rabbits of the same age; histologic changes were minimal. IgG antibodies in sera from proteinuric rabbits or eluted from their kidneys reacted by indirect immunofluorescence with antigens distributed (discontinuously) along the glomerular capillary walls, and in some cases within the walls of small arteries of normal rabbit kidney sections. By indirect immunoperoxidase electron microscopy, the reactive antigens were present at the surfaces of the epithelial cell foot processes where they abut the GBM. This spontaneous glomerulonephritis appears to involve fixation of antibodies to antigens distributed in a discontinuous pattern in the glomerular capillary wall. The mechanism would be much like that causing anti-GBM antibody glomerulonephritis, except that the glomerular antigen is different. Possibly some forms of glomerulonephritis develop in humans as a result of a similar process. Glomerulonephrite spontanee chez des lapins: Role d'un antigene capillaire glomerulaire. Une glomerulonephrite patente, detectee par une proteinurie anormale, s'est produite chez 3,3% de jeunes (2,5 kg) lapins mâles New Zealand white (NZW). Histologiquement, une glomerulonephrite mixte, extra membraneuse et proliferative, moderee ou moyenne, a ete observee. Les depots glomerulaires d'IgG et de C3, et les resultats de la microscopie electronique n'etaient pas typiques d'une accumulation de complexes immuns circulants, ni ne suggeraient d'anticorps anti-membrane basale glomerulaire (GBM). Des depots glomerulaires segmentaires et moins intenses, d'IgG ont ete trouves chez 48% des lapins NZW non proteinuriques du meme âge; les modifications histologiques etaient minimes. Les anticorps IgG des serums de lapins proteinuriques ou elues a partir de leurs reins reagissaient par immunofluorescence indirecte avec des antigenes distribues (de facon discontinue) le long des parois capillaires glomerulaires, et dans certains cas dans les parois de petites arteres de sections de reins de lapin normal. En microscopie electronique avec immunoperoxidase indirecte, les antigenes reactifs etaient presents sur les surfaces des pedicelles des cellules epitheliales, la ou ils sont en contact avec la GBM. Cette glomerulonephrite spontanee semble mettre en jeu la fixation d'anticorps a des antigenes distribues d'une facon discontinue sur la paroi capillaire glomerulaire. Son mecanisme pourrait etre voisin de celui responsable de la glomerulonephrite a anticorps anti-GBM, mis a part l'antigene glomerulaire qui est different. Il est possible que certaines formes de glomerulonephrite se developpent chez l'homme selon un processus identique.