scholarly journals An Investigation of the Antigenic Characteristics of the Renal Glomerulus in the Rat

2021 ◽  
Author(s):  
◽  
Maurice James Nicol
Keyword(s):  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
Animal Models ◽  
Basement Membrane ◽  
Glomerular Basement Membrane ◽  
Immune Complexes ◽  
Capillary Wall ◽  
Glomerular Capillary Wall ◽  
Glomerular Capillary

<p>The finding of a granular deposition of immunoglobulin in the kidney in experimental animal models of glomerulonephritis has been been interpreted as resulting from the random deposition of immune complexes in the glomeruli. Recent data suggests that although immune complex deposition may be an important factor in some forms of glomerulonephritis, the in situ formation of immune complexes between circulating anti-kidney antibodies and fixed glomerular capillary wall antigens may also be a significant factor in the pathogenesis of some animal models of glomerulonephritis. To examine the characteristics of discontinuously represented glomerular capillary wall antigens in the rat, monoclonal antibodies were generated against a glomerular plasma membrane fraction, depleted of glomerular basement membrane, prepared from isolated Lewis rat glomeruli. A total of 17 hybridomas, generated from the fusion of splenocytes obtained from mice immunised with the glomerular membrane fraction produced monoclonal antibodies which reacted with discontinuously represented antigens in the glomerulus and renal tubules. One further hybridoma secreted a monoclonal antibody which reacted with an antigen present on glomerular and tubular nuclear membranes. No hybridomas were produced which secreted a monoclonal antibody which reacted with linearly arrayed glomerular basement membrane antigens. Two of these monoclonal antibodies, both of the IgM subclass and code-named PH7 and SC5, produced a heavy granular glomerular staining pattern when examined by indirect immunofluorescence microscopy. Neither monoclonal antibody was kidney specific, with reactivity being demonstrated with a number of non-renal tissues. When administered intravenously to normal Lewis rats both SC5 and PH7 induced a mild proteinuric lesion. The proteinuria was not associated with histopathological changes at the light or electron microscope level. Immunoblotting experiments revealed that SC5 reacted predominantly with a protein band of 96 kDa present in detergent extracts of isolated glomeruli and glomerular plasma membranes. PH7 was shown to react with three low molecular weight proteins of 14, 13 and 11 kDa The findings of this study demonstrate the potential for a nephritogenic response to occur following the in situ formation of immune complexes between circulating anti-kidney antibodies and discontinuously arrayed non-glomerular, basement membrane glomerular capillary wall antigens characterised by granular immunofluorescence patterns,in animal models of glomerulonephritis.</p>

scholarly journals An Investigation of the Antigenic Characteristics of the Renal Glomerulus in the Rat

2021 ◽  
Author(s):  
◽  
Maurice James Nicol
Keyword(s):  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
Animal Models ◽  
Basement Membrane ◽  
Glomerular Basement Membrane ◽  
Immune Complexes ◽  
Capillary Wall ◽  
Glomerular Capillary Wall ◽  
Glomerular Capillary

<p>The finding of a granular deposition of immunoglobulin in the kidney in experimental animal models of glomerulonephritis has been been interpreted as resulting from the random deposition of immune complexes in the glomeruli. Recent data suggests that although immune complex deposition may be an important factor in some forms of glomerulonephritis, the in situ formation of immune complexes between circulating anti-kidney antibodies and fixed glomerular capillary wall antigens may also be a significant factor in the pathogenesis of some animal models of glomerulonephritis. To examine the characteristics of discontinuously represented glomerular capillary wall antigens in the rat, monoclonal antibodies were generated against a glomerular plasma membrane fraction, depleted of glomerular basement membrane, prepared from isolated Lewis rat glomeruli. A total of 17 hybridomas, generated from the fusion of splenocytes obtained from mice immunised with the glomerular membrane fraction produced monoclonal antibodies which reacted with discontinuously represented antigens in the glomerulus and renal tubules. One further hybridoma secreted a monoclonal antibody which reacted with an antigen present on glomerular and tubular nuclear membranes. No hybridomas were produced which secreted a monoclonal antibody which reacted with linearly arrayed glomerular basement membrane antigens. Two of these monoclonal antibodies, both of the IgM subclass and code-named PH7 and SC5, produced a heavy granular glomerular staining pattern when examined by indirect immunofluorescence microscopy. Neither monoclonal antibody was kidney specific, with reactivity being demonstrated with a number of non-renal tissues. When administered intravenously to normal Lewis rats both SC5 and PH7 induced a mild proteinuric lesion. The proteinuria was not associated with histopathological changes at the light or electron microscope level. Immunoblotting experiments revealed that SC5 reacted predominantly with a protein band of 96 kDa present in detergent extracts of isolated glomeruli and glomerular plasma membranes. PH7 was shown to react with three low molecular weight proteins of 14, 13 and 11 kDa The findings of this study demonstrate the potential for a nephritogenic response to occur following the in situ formation of immune complexes between circulating anti-kidney antibodies and discontinuously arrayed non-glomerular, basement membrane glomerular capillary wall antigens characterised by granular immunofluorescence patterns,in animal models of glomerulonephritis.</p>

scholarly journals Reduction in Glomerular Heparan Sulfate Correlates with Complement Deposition and Albuminuria in Active Heymann Nephritis

1999 ◽  
Vol 10 (8) ◽  
pp. 1689-1699 ◽  
Author(s):  
C. J. ILSE RAATS ◽  
MARIKEN E. LUCA ◽  
MARINKA A. H. BAKKER ◽  
ANNEMIEKE VAN DER WAL ◽  
PETER HEERINGA ◽  
...  
Keyword(s):  
Basement Membrane ◽  
Heparan Sulfate ◽  
Glomerular Basement Membrane ◽  
Core Protein ◽  
Control Level ◽  
Staining Intensity ◽  
Capillary Wall ◽  
Glomerular Capillary Wall ◽  
Glomerular Capillary ◽  
Heymann Nephritis

Abstract. In a time-study of active Heymann nephritis, the expression of agrin, the main heparan sulfate proteoglycan in the glomerular basement membrane, was analyzed in relation to deposition of IgG and complement in the glomerular capillary wall and the development of albuminuria. Binding of IgG autoantibodies to the glomerular capillary wall could be detected from 2 wk onward, followed by activation of complement after 6 wk. Progressive albuminuria developed from 6 wk onward to a level of 274 ± 68 mg/18 h at week 12. The staining intensity for the agrin core protein decreased slightly, and the staining intensity for the heparan sulfate stubs that were still attached to the core protein after heparitinase digestion remained normal. From week 6 onward, however, a progressive decrease was seen in the staining of two monoclonal antibodies (mAb) directed against different epitopes on the heparan sulfate polysaccharide side chain of agrin (to 35 and 30% of the control level, respectively, at week 12, both mAb P = 0.016). Moreover, albuminuria was inversely correlated with heparan sulfate staining as revealed by these antibodies (rs = -0.82 and rs = -0.75, respectively, both mAb P < 0.0001). This decrease in heparan sulfate staining was due to a progressive reduction of glomerular heparan sulfate content to 46 and 32% of control level at week 10 and week 12 of the disease, respectively, as measured biochemically. It is speculated that the observed decrease in glomerular heparan sulfate in active Heymann nephritis is due to complement-mediated cleavage of heparan sulfate, resulting in an increased permeability of the glomerular basement membrane to macromolecules.

Alterations in glomerular permeability in streptozotocin-induced diabetic rats

1996 ◽  
Vol 86 (2) ◽  
pp. 57-62 ◽  
Author(s):  
RB Boyd ◽  
VW Thompson ◽  
J Atkin
Keyword(s):  
Basement Membrane ◽  
Glomerular Basement Membrane ◽  
Diabetic Rats ◽  
Capillary Wall ◽  
Diabetic Rat ◽  
Electron Microscopic ◽  
Glomerular Permeability ◽  
Glomerular Capillary Wall ◽  
Capillary Lumen ◽  
Glomerular Capillary

The alteration in glomerular basement membrane permeability associated with microangiopathy in streptozotocin-induced diabetic rats was studied by determining the movement across the glomerular basement membrane of anionic ferritin probes injected into rats at different points in the development of the disease. Visualization of the concentration gradient of anionic ferritin and changes in ultrastructure was accomplished by electron microscopic examination of renal tissue prepared from both control and diabetic rats. In all control rats, the anionic ferritin did not leave the glomerular capillary lumen, nor were there any changes in the normal morphology of the glomerular capillary wall. In the diabetic animals, the concentration of anionic ferritin shifted from the capillary lumen in the abluminal direction. Distinct morphologic changes, such as widening of endothelial intercellular junctions, focal detachment of podocyte foot processes, and extensive thickening of the glomerular basement membrane, were noted in the diabetic rat, and these changes appear to correlate with the observed increase in permselectivity of anionic ferritin across the glomerular capillary wall.

Assessment of the charge selectivity of glomerular basement membrane using Ficoll sulfate

1998 ◽  
Vol 274 (5) ◽  
pp. F889-F896 ◽  
Author(s):  
Glen R. Bolton ◽  
William M. Deen ◽  
Barbara S. Daniels
Keyword(s):  
Ionic Strength ◽  
Basement Membrane ◽  
Serum Albumin ◽  
Glomerular Basement Membrane ◽  
Capillary Wall ◽  
Physical Factors ◽  
Hydraulic Permeability ◽  
Glomerular Capillary Wall ◽  
Glomerular Capillary ◽  
Charge Selectivity

The extent to which the glomerular basement membrane (GBM) contributes to the charge selectivity of the glomerular capillary wall has been controversial. To reexamine this issue, the size and charge selectivity of filters made from isolated rat GBM were assessed, using polydisperse Ficoll and Ficoll sulfate as test macromolecules. Ficoll sulfate, a novel tracer with spherical shape synthesized for this purpose, exhibited little or no binding to serum albumin, thereby avoiding a major difficulty that has been reported with dextran sulfate. The sieving coefficients of Ficoll sulfate were not different from those of Ficoll at physiological ionic strength, although the values for Ficoll sulfate were depressed at low ionic strength. These results confirm that the GBM possesses fixed negative charges but suggest that its charge density is insufficient to confer significant charge selectivity under physiological conditions, where electrostatic interactions are relatively well screened. The sieving coefficients of Ficoll sulfate and Ficoll were elevated significantly and by similar amounts when bovine serum albumin (BSA) was present in the retentate at 4 g/dl. This could be explained as the combined effect of two nonspecific physical factors, namely, the reduction in filtration velocity due to the osmotic pressure of BSA and the effect on macromolecular partitioning of repulsive solute-solute interactions. The view that BSA does not affect the intrinsic properties of the GBM is supported also by the absence of an effect on the hydraulic permeability of isolated GBM. The sieving coefficient of BSA was roughly half that of Ficoll or Ficoll sulfate of similar Stokes-Einstein radius. Given the finding of negligible charge selectivity, this difference may be attributed to the nonspherical shape of albumin. The results suggest that, to the extent that isolated GBM is similar to GBM in vivo, the charge selectivity of the glomerular capillary wall must be due to the endothelial and/or epithelial cell layers.

Structure and development of the glomerular capillary wall and basement membrane

1987 ◽  
Vol 253 (5) ◽  
pp. F783-F794 ◽  
Author(s):  
D. R. Abrahamson
Keyword(s):  
Basement Membrane ◽  
Membrane Fusion ◽  
Molecular Mechanisms ◽  
Specific Binding ◽  
Mesenchymal Cells ◽  
Capillary Wall ◽  
Collagen Type Iv ◽  
Glomerular Capillary Wall ◽  
Glomerular Capillary ◽  
Filtration Barrier

The renal glomerular epithelium, Bowman's capsule, and tubule originate from a condensate of mesenchymal cells induced to undergo epithelial differentiation by a branch of the uretic bud. These nephrogenic cells aggregate and begin synthesizing the basement membrane molecules collagen type IV, heparan sulfate proteoglycans, and laminin as shown by immunofluorescence microscopy. Soon, the primitive nephron is invaginated by mesenchymal cells that establish the glomerular endothelium. Electron microscopy, metabolic labeling, and immunocytochemical techniques show that the endothelium and epithelium of early stage glomeruli each synthesize a basement membrane that appears to fuse, giving rise to the glomerular basement membrane (GBM). As development progresses, however, bulk GBM biosynthesis by the endothelium greatly diminishes or ceases. In contrast, GBM assembly by the epithelial podocytes continues and segments of new GBM appear beneath developing foot processes. In vivo labeling experiments with anti-laminin antibodies have shown that this new GBM derived from podocytes is subsequently spliced into existing GBM as capillary loop diameters expand. Molecular mechanisms for basement membrane fusion or splicing are not presently known but may involve partial enzymatic digestion and specific binding interactions among GBM components. The developing glomerular capillary wall, which filters plasma from very early stages, becomes decreasingly permeable to perfused macromolecules such as ferritin or immunoglobulin as the glomerulus matures. Evidence from immunolabeling studies showing that some monoclonal IgGs bind to the GBM only at specific developmental stages also indicates that temporal biochemical changes take place during GBM assembly. Such changes could include molecular rearrangement during basement membrane fusion and splicing and/or enzymatic and compositional modifications during maturation of the filtration barrier.

scholarly journals Nondissociating cationic immune complexes can deposit in glomerular basement membrane.

1983 ◽  
Vol 158 (5) ◽  
pp. 1561-1572 ◽  
Author(s):  
T Caulin-Glaser ◽  
G R Gallo ◽  
M E Lamm
Keyword(s):  
Basement Membrane ◽  
Glomerular Basement Membrane ◽  
Immune Complexes ◽  
Gel Filtration ◽  
Lamina Densa ◽  
Net Charge ◽  
The Subject ◽  
Covalently Linked ◽  
Circulating Antibody

The mechanisms by which immune complexes deposit in the glomerular basement membrane have been the subject of much debate, with the relative importance of direct deposition of circulating immune complexes (IC) vs. formation of IC in situ from the binding of circulating antibody to structural or exogenous planted antigen being at issue. In order to determine whether intact IC can deposit as such, covalently linked IC were prepared by a two-step reaction involving the bifunctional reagent toluene-2,4-diisocyanate (TDI), the antigen bovine gamma globulin (BGG), and rabbit anti-BGG antibody. Antigen and antibody were covalently cross-linked, with little self-linkage of antigen or antibody, and IC were purified by gel filtration. The net charge of the complexes was varied by chemical means, either before or after IC formation. When cationic IC were injected intravenously into mice, there was codeposition of antigen and antibody diffusely in the glomerular basement membrane (GBM), and deposits were observed ultrastructurally in the laminae rarae, interna and externa, and the lamina densa. Thus, under conditions of restricted appropriate charge, intact IC can cross the glomerular basement membrane and deposit in subepithelial sites without being excluded by size alone.

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