Transfer of an autoimmune nephrosis in the rat by means of lymph node cells

Proteinuria in membranous lupus nephritis: the pathology is in the podocyte

BACKGROUND

Patients with membranous lupus glomerulonephritis (MLN) can present with a broad range of urine protein excretion. The glomerular lesion underlying this functional abnormality has been presumed to be immune complexes which aggregate in the subepithelial area. However, the amount of proteinuria often fails to correlate with the quantity of immune deposits demonstrable on fluorescent and electron microscopy. The purpose of this study is to determine the correlation of alterations of the morphologic components of the glomerular capillary wall with the amount of proteinuria in MLN.

DESIGN

We conducted a retrospective clinicopathologic study of patients with lupus nephritis (n=236). In those with pure MLN and proteinuria (n=20), the degree of immune aggregates in the capillary walls and mesangium was detailed using fluorescent and electron microscopy. The degree of foot process effacement (FPE) was detailed using electron microscopy.

RESULT

Eleven patients had nephrotic range proteinuria (≥ 3 g proteinuria/g creatinine (g/g)) and nine demonstrated subnephrotic range proteinuria (<3 g/g) (nephrotic, 8.3 ± 5.1 g/g vs. subnephrotic, 1.63 ± 0.83 g/g, p=0.001). All patients demonstrated peripheral capillary wall granular deposits by immunofluorescence microscopy, and the degree of moderate (2+) to severe (3+) deposition was not different (nephrotic, 8/11, 73% vs. subnephrotic, 5/9, 55%, p=0.64). By electron microscopy, FPE (88.6 ± 11% vs. 48.3 ± 36.1%, p=0.002) and foot process width (1798 ± 736 nm vs. 1000 ± 333 nm, p=0.008) was greater in the nephrotic group compared with subnephrotic. There were no other histopathologic differences between the groups.

CONCLUSIONS

In patients with MLN, a distinguishing morphologic feature of those with nephrotic range proteinuria is diffuse visceral epithelial cell FPE. We conclude that nephrotic range proteinuria in patients with MLN may be a manifestation of concomitant glomerular visceral epithelial cell dysfunction.

Association of glomerular podocytopathy and nephrotic proteinuria in mesangial lupus nephritis

We investigated a series of patients with systemic lupus erythematosus (SLE), who had sparse subepithelial and mesangial immune deposits. Our goal was to determine structure: function correlation. We examined whether proteinuria correlated with either capillary wall immune aggregate formation or abnormal podocyte morphology. Renal biopsies from patients with sparse (two or fewer subepithelial or intramembranous electron dense deposits per glomerular capillary loop) immune deposits and podocyte effacement were studied. Patients fulfilled criteria for the diagnosis of SLE. Cases were excluded if the biopsy showed endocapillary proliferation or necrosis. Eighteen biopsies were studied, five from patients with nephrotic range proteinuria (> or =3 g/day) and 13 from patients with non-nephrotic proteinuria (<3 g/day). The five nephrotic patients had a mean foot process effacement of 48% +/- 39% (range 10-100%). Thirteen non-nephrotic patients had a mean foot process effacement of 11.7% +/- 8% (range 0-20%). The only distinguishing morphologic finding associated with nephrotic range proteinuria was diffuse foot process effacement. No correlation between subepithelial deposits and proteinuria was observed. There were no other histologic differences between the nephrotic and non-nephrotic patients. Among these patients, the nephrotic syndrome appears best correlated with podocytopathy rather than subepithelial electron dense deposits, mesangial deposits, or mesangial hypercellularity.

Il-4 therapy prevents the development of proteinuria in active Heymann nephritis by inhibition of Tc1 cells

The role of IL-4, a key Th2 cytokine, in promoting or inhibiting active Heymann nephritis (HN) was examined. HN is induced by immunization with Fx1A in CFA, and proteinuria in HN is associated with subepithelial IgG and C3 deposition and infiltration of CD8(+) T-cytotoxic 1 (Tc1) cells and macrophages into glomeruli, as well as induction of Abs to Crry. Treatment with rIL-4 from the time of Fx1A/CFA immunization stimulated an earlier IgG1 response to Fx1A, induced anti-Crry Abs, and up-regulated IL-4 mRNA in lymphoid tissue, but did not alter proteinuria. Treatment with MRCOx-81, an IL-4-blocking mAb, resulted in greater proteinuria, which suggests endogenous IL-4 regulated the autoimmune response. Delay of rIL-4 treatment until 4 wk post-Fx1A/CFA immunization and just before the onset of proteinuria prevented the development of proteinuria and reduced Tc1 cell infiltrate in glomeruli. Delayed treatment with IL-4 had no effect on titer or isotype of Abs to Fx1A or on Ig, C3, and C9 accumulation in glomeruli. Treatment with rIL-13, a cytokine that alters macrophage function such as rIL-4, but has no direct effect on T or B cell function, reduced glomerular macrophage infiltrate, but did not prevent proteinuria or CD8+ T cell infiltrate. Anti-Crry Abs were paradoxically only induced with rIL-4 therapy, not in HN controls with proteinuria. It was concluded that the rIL-4 effect was probably by inhibition of Tc1 cells, which normally mediate the glomerular injury that results in proteinuria.

Permanent CD8(+) T cell depletion prevents proteinuria in active Heymann nephritis

Active Heymann nephritis (HN) is a rat model of human idiopathic membranous nephropathy in which injury is thought to be mediated by membrane attack complex of complement (MAC) activated by antibody (Ab) to glomerular epithelial cells. Recent work has shown that HN develops in C6-deficient rats which cannot assemble MAC, and that infiltration of activated cytotoxic CD8(+) T cells and macrophages into glomeruli coincides with proteinuria. This study examined the role of CD8(+) T cells in mediating glomerular injury in HN by permanent CD8(+) cytotoxic T cell depletion via adult thymectomy (ATx) and anti-CD8 mAb. Groups of rats were depleted of CD8(+) T cells either before immunization for HN or 6 wk after immunization when Ab responses and glomerular IgG deposition were well established. These were compared with groups of HN, ATx/HN, and complete Freund's adjuvant (CFA) controls. Neither group of CD8(+) T cell-depleted rats developed proteinuria, although there was normal development and deposition of Ab. CD8(+) T cell-depleted rats developed neither T cell or macrophage infiltrates nor their effector cytokines, which are present in glomeruli of rats with HN. Examination of lymph node (LN) draining sites of immunization showed these findings were not explained by altered immune events within these LNs. It was concluded that CD8(+) cytotoxic T cells are essential to the mediation of glomerular injury in HN and may be relevant to the pathogenesis and treatment of membranous nephropathy.

In vitro studies of ulcerative colitis. II. Cytotoxic action of white blood cells from patients on human fetal colon cells

Freshly isolated fetal human colon cells were labeled with (32)P-orthophosphate or (14)C-amino acids and exposed to white blood cells from children with ulcerative colitis or from healthy controls. Exposure of the colon cells to patients' white cells led to a rapid isotope release, significantly higher than that obtained with normal white cells. After 150 minutes of incubation, 75 per cent of the total isotope present was found in the media of the colitis samples but only 40 per cent in those of the controls. Consistent results were obtained with white blood cells from 14 patients and 18 healthy individuals. Similar results were obtained with either fresh white cells or with white cells aged for 12 to 18 hours and consisting to 60 to 70 per cent of lymphocytes and to 20 to 30 per cent of large mononuclear cells. No specific cytotoxic activity could be conferred onto normal white cells by pretreating them with patients' serum containing antibodies against colon antigen. The cytotoxic action of the patients' white cells was immunologically specific, since no difference from the controls was found in the isotope release when cells from other organs or animals were similarly treated. Preliminary experiments suggested that the patients' white cells could be desensitized by pretreating them with colon extract. For obtaining a significant cytotoxic effect of the patients' white cells, the presence of 10 to 20 per cent of fresh guinea pig or human serum in the incubation medium was required.

Glomerulonephritis induced in sheep by injections of heterologous glomerular basement membrane and Freund's complete adjuvant

Sheep injected every 2 weeks with heterologous GBM and Freund's adjuvant by any one or combination of the following routes: intramuscular, subcutaneous, or intradermal, develop uniformly a fulminating, extracapillary glomerulonephritis, invariably fatal within 27 to 90 days after the first injection. The chief histologic feature is marked fibroepithelial proliferation of Bowman's capsule with crescent formation. The appearance of the lesions resembles the acute, subacute, and chronic stages of human glomerulonephritis, and depends on when the animal was sacrificed. Freund's adjuvant or heterologous GBM alone does not produce such a nephritis. The combination of placental tissue and Freund's adjuvant under the present experimental conditions was also unable to produce a nephritis. The clinical course, increase in nitrogen retention, evolution of renal lesions, and death, all describe a fulminating disease. The disease most characteristically resembles fatal, fulminating human subacute glomerulonephritis. The changes in serum proteins, decrease in serum albumin, and increase in serum globulin, occurred approximately the same in both the GBM-treated and the control adjuvant group. Similar changes have been reported from hyperimmunization alone, and so it is not clear how much these changes are due to immunization and how much is due to the nephritic process. The changes in serum cholesterol were not considered statistically significant. Circulating serum antibodies which localized (by fluorescent antibody technique in vitro) on basement membrane structures of the heterologous donor kidney antigen or which produced nephritis in the heterologous donor species (rat and dog) were found in serum of sheep sick or dying of nephritis. The passive transfer of nephritis by serum antibodies marks the first successful instance of transfer of nephritis by serum antibody to a heterologous species from an animal which had developed nephritis itself. The serum antibodies involved in the transfer of disease to the donor species appear to be unrelated to the mediators of nephritis in the sheep and may represent only the previously known heteronephrotoxic antibodies. By various biologic criteria the sheep nephritis presumably occurs by an autoimmune mechanism. However, it is not known whether the sheep nephritis is mediated by sensitized cells and/or antibodies. The latent period was estimated to end about 16 to 71 days after the first injection. Azotemia was estimated to begin about 17 to 78 days after the first injection. Proteinuria and azotemia began approximately 23 and 13 days before death. The rapid progression to a fatal termination defined the fulminating character of this disease.

Role of T cells in the mediation of Heymann nephritis. ii. Identification of Th1 and cytotoxic cells in glomeruli

The role of immunoglobulin (Ig) and complement as mediators of Heymann nephritis (HN) has been questioned by recent studies showing that HN can be induced in a C6-deficient rat that cannot assemble the membrane attack complex of complement. Also, the severity of HN can be reduced by therapy directed at CD8+ T cells, which has no effect on antibody (Ab) production or immune deposits. To identify whether T cells may contribute to the glomerular injury of active HN in Lewis rats, the mononuclear infiltrate and cytokine mRNA in glomeruli and kidney interstitium were examined. Groups of Lewis rats immunized with Fx1A in CFA developed HN, and were compared to controls that received CFA only. Proteinuria, the marker of glomerular filtration barrier dysfunction, was absent at four weeks but present at eight weeks in HN. Serum anti-Fx1A Ab and glomerular Ig were present in HN at both time points. Immunoperoxidase staining with monoclonal Abs identified, at eight weeks, a glomerular infiltrate of CD4+ and CD8+ T cells, and macrophages, but not NK cells. Semiquantitative RT-PCR of isolated glomeruli at eight weeks demonstrated expression of cytokine mRNA for Th1 CD4+ cells (IFN-gamma and TNF-beta/LT, but not IL-2), cytotoxic CD8+ T cells (granzyme A and perforin), and macrophages (TNF-alpha and IL-10), but not Th2 CD4+ cells (no increase in IL-4, IL-5 and IL-6). At eight weeks, the cellular infiltrate and pattern of cellular activation in glomeruli was different to that in renal cortex. In the cortical infiltrate CD8+ cells were a lesser component, and NK cells were increased, as were CD4+ cells and macrophages. RT-PCR identified increased cytokine mRNA for macrophages, Th1 and Th2 cells, but not cytotoxic effector T cells. At four weeks, T cells including CD4+ and CD8+ cells were identified in the isolated glomeruli of rats with HN, but there was no increase in cytokine mRNA expression. There was no infiltrate or increase in cytokine mRNA detected in renal cortex at four weeks. Anti-Fx1A Ab's and glomerular deposition of Ig develop many weeks before the onset of proteinuria, when there is only a small cellular infiltrate present. The progressive development of infiltrates of activated T cells, principally Th1 and cytotoxic effector cells, and macrophages, within glomeruli is coincident with the development of proteinuria. These findings raise the possibility that these cells contribute to the mediation of the glomerular injury and proteinuria of HN.

PASSIVE TRANSFER OF ADJUVANT ARTHRITIS BY LYMPH NODE OR SPLEEN CELLS

All adjuvant-induced arthritis has been passively transferred in a highly inbred strain of rats by transfer of viable lymph node or spleen cells, but not thymus cells, to normal recipients. After an interval averaging 4.3 days recipients developed arthritis, whereas animals actively sensitized with adjuvant never developed disease before the 9th day (average 11.3 days). The transferred disease had all of the gross and pathological characteristics of primary disease, except for a lesser severity. Control studies using non-viable cells either of lymphoidal or other tissue origin were always negative. It is concluded that adjuvant arthritis is the result of an immunologic reaction which is perhaps similar to delayed hypersensitivity. The antigen in this reaction so far remains obscure.

Non-systemic glomerulonephritis: exposure to nephro- and immunotoxic chemicals predispose to immunologic harassment

Glomerulonephritis is thought to be caused by immune complexes trapped or formed in the glomeruli. But immune complexes are found in the glomeruli of many normal mammals and of patients with non-renal diseases, and immune complexes trapped or formed experimentally in the glomeruli induce mild proteinuria at most suggesting that additional factors must be responsible. An induction of serious renal damage in experimental glomerulonephritis demands a chronic supply of antigen, rarely seen in human glomerulonephritis; or the use of heterologous antibodies, a design with questionable clinical relevance; or immuno- and nephrotoxic chemicals; or Freund's adjuvant which is also nephrotoxic. It is therefore suggested that the pathogenesis of human non- systemic glomerulonephritis includes exposure to nephro- and immunotoxic chemicals, the deposition of glomerular immune complexes being secondary. The hypothesis has clinical support: a majority of patients have been exposed to such chemicals, mainly hydrocarbons; and the tubulointerstitial changes in glomerulonephritis are better correlated to renal function and clinical course than are the glomerular changes. The chemicals enhance or derange immunizations and sensitize the kidneys to immunological reactions.

Syngeneic sensitization of mouse lymphocytes on monolayers of thyroid epithelial cells. III. Induction of thyroiditis by thyroid-sensitized T lymphoblasts

During in vitro sensitization of CBA spleen lymphocytes on syngeneic monolayers of either thyroid epithelial cells (TEC) or fibroblasts, stimulation occurs, as assessed by thymidine incorporation and lymphoblast generation. When lymphoblasts generated on syngeneic TEC are injected either into thyroid lobes of intact CBA recipients or i.v., thyroiditis appears at least 21 days after injection. Thyroiditis is assessed by both optical and electron microscopic blind studies and by the presence of antibodies in the sera directed against mouse thyroglobulin. In contrast, control animals which received identical numbers of lymphoblasts generated on syngeneic fibroblasts behaved as normal. Thyroiditis was also induced using pure thyroid-sensitized T lymphoblasts. This is the first report showing the role of T lymphocytes in the induction of experimental autoimmune thyroiditis.

The pathogenesis of experimental membranous glomerulonephritis induced with homologous nephritogenic tubular antigen

The renal tubular epithelial antigen (Tub-Ag) of rats was solublized by Pronase and purified by gel filtration and acrylamide gel electrophoresis. Purified Tub-Ag was a glycoprotein with S20,W value of 8.4. Utilizing radiolabeled Tug-Ag, a sensitive radioimmunoassay for Tub-Ag and homologous antibody (anti-Tub-Ag) was developed. Tub-Ag activity associated with a protein of the same molecular size was demonstrated in the serum, as well as in Pronase extracts of all the organs tested, including kidney, liver, lung, spleen, intestine, stomach, and heart. The physiochemical properties of the Tub-Ag of rats and its distribution were essentially the same as the Tub-Ag of humans, which had been found in immune deposits in the kidney of some patients with idiopathic membranous glomerulonephritis. Rats were immunized with the purified Tub-Ag emulsified in Freund's complete adjuvant and followed for Tub-Ag and anti-Tub-Ag in the serum, as well as for proteinuria and immunohistological changes in the kidney. Serum Tub-Ag dropped sharply after 20 days, when anti-Tub-Ag appeared in the circulation. Persistent, massive proteinuria appeared still later, more than 30 days after injection, when anti-Tub-Ag disappeared and Tub-Ag reappeared in the serum of some of those rats. In others, anti-Tub-Ag in the serum persisted throughout the observation period of 90 days. The pathology of the kidney of the rats with proteinuria was that of a typical membranous glomerulonephritis; thickening of glomerular capillary walls with granular deposits of gamma-globulin and Tub-Ag was observed. On the basis of these results, Tub-Ag in the serum, probably released from cellular membranes of various organs as a physiological metabolite, is considered to maintain the pathological process in the kidney by providing the antigen continuously to form immune complexes.

Cellular immunity in experimental glomerulonephritis of rats. II. A sequential study of immunological events occurring during development of the disease

The exact roles played by specific antibody, circulating antigen—antibody complexes and cellular immunity in the causation of experimental glomerulonephritis of rats (EGN) need clarification and a sequential study of these factors was therefore undertaken. Rats immunized with renal tubular antigen and studied for humoral response only (group I) produced neither precipitating nor 2- or 48-hour PCA antibodies but did have an antibody titre by an immunofluorescent test against the proximal portion of the proximal convoluted tubular cells by the second to sixth week post-immunization in six of six animals. A C1_q test for antigen—antibody complexes became positive in most rats at the time of onset of proteinuria. Rats in group II were studied for cellular immunity to the renal tubular antigen. Skin tests did not become positive until approximately the time of onset of proteinuria when peripheral blood lymphocyte cultures were also stimulated in seven of nine rats tested. Direct immunofluorescence of the kidneys from this group revealed a linear deposition of γG and renal tubular antigen along the glomerular basement membrane. Since both cellular immunity and antigen—antibody complexes involving the renal tubular antigen were present at the onset of proteinuria, both modalities may play a significant role in EGN.

Transfer amyloidosis. I. Studies on the transfer of various lymphoid cells from amyloidotic mice to syngeneic nonamyloidotic recipients. II. Induction of amyloidosis in mice with spleen, thymus and lymph node tissue from casein-sensitized syngeneic donors

Lymphoid cells from various lymphoid organs were transferred from amyloidotic mice to normal syngeneic recipients. The recipients were treated with nitrogen mustard. Only the recipients of spleen cells developed amyloidosis. Furthermore, slices of spleen, thymus and lymph node from casein-sensitized mice were transplanted to kidneys of normal syngeneic mice. The recipients were treated with ten casein injections, and they all developed amyloidosis. The results from both experiments indicate that amyloid is formed by macrophages due to a stimulation of these cells with both antigen and an amyloid-inducing factor released from the pyroninophilic lymphoid cells.

Experimental glomerulonephritis in the mouse. I. The model

Mice immunized with dog glomerular basement membrane in Fruend's complete adjuvant uniformly developed severe renal lesions. A prominent event in many animals appeared to be mononuclear cell accumulation around small renal blood vessels. Glomerular lesions characterized by hypercellularity, thickening of basement membrane, necrosis, and well marked crescent formation were noted. Immunofluorescent and antibody elution studies from the kidneys of animals immunized with dog GBM demonstrated the presence of specific anti-GBM antibody which could be detected in mouse glomeruli 4 weeks after initial immunization.

Autosensitization in vitro

Autosensitization of rat or mouse lymphoid cells against syngeneic fibroblast antigens was induced in cell culture. Rat lymphoid cells autosensitized by this method were able to produce immunospecific lysis of syngeneic target fibroblasts in vitro or GvH reactions in newborn rats. Autosensitized mouse spleen cells mediated similar GvH reactions when injected into newborn mice. The nature of the system used to induce immunity in vitro appears to argue against the possibility that lymphocytes capable of reacting against self-antigens could arise by mutation in cell culture. Hence, it is likely that cells potentially reactive against self-antigens preexisted in the lymphoid cell donors. The ability of autosensitized cells to mediate immune reactions in vivo suggests that the immunogenic self-antigens present on sensitizing fibroblasts also were accessible in the intact animals. Loss of natural self-tolerance in vitro, therefore, can be explained most simply by the existence of lymphocytes which are reversibly tolerant to self. Hence, ontogenic elimination of potentially self-reactive cells may not be the only basis for natural tolerance. Regulatory mechanisms, such as antigen excess, may have to function in vivo to prevent differentiation of self-tolerant lymphocytes. These regulatory mechanisms appear to be annulled in the cell-culture system. The present system thus may offer a new approach to studies of tolerance and regulation of cellular immunity.

Lymphocytic responses to streptococcal antigens in glomerulonephritic patients

The lymphocytes from patients with progressive glomerulonephritis showed significant inhibition of cell migration in the presence of group A streptococcal particulate antigens. Marked increases in the level of DNA synthesis of these lymphocytes were also observed after contact with these antigens. Lymphocytes from patients with unrelated renal disorders exhibited minimum reactivity to streptococcal antigens.

The serology of autologous immune complex nephritis in the rat

The serological response has been studied in rats developing autoimmune complex nephritis, following injection of chemically modified kidney antigen. The results suggest that a change takes place from IgM to both IgM and IgG anti-kidney antibodies. This response can be distinguished from the naturally occurring IgM antitissue antibodies.

Autologous immune complex nephritis induced with renal tubular antigen. I. Identification and isolation of the pathogenetic antigen

The nephritogenic antigen, responsible for the immunogenic stimulus in experimental allergic glomerulonephritis induced with tubular antigen, has been identified as a renal tubular epithelial (RTE)-specific antigen and has been isolated in a relatively purified form. This antigen, RTE-alpha(5), is a distinct and antigenically specific lipoprotein of high density which is derived primarily from the brush border of proximal convoluted tubular epthelium of the rat kidney. It has been suggested that this molecule may be a plasma membrane subunit. Immunization of rats with as little as 3 microg N of RTE-alpha(5) in complete Freund's adjuvant has effectively induced this form of membranous glomerulonephritis. RTE-alpha(5) is not a constituent of normal rat glomeruli; however, with the onset of autologous immune complex nephritis it is deposited in a granular fashion along glomerular capillary walls indistinguishable from the deposits of gamma-globulin and complement. The antigenic specificity of this antigen and its tissue derivation has been explored, and the observations support the autologous immune complex pathogenesis of the glomerulonephritis induced in rats by immunization with renal tubular antigen.

Autologous immune complex nephritis induced with renal tubular antigen. II. The pathogenetic mechanism

The pathogenetic mechanism involved in a form of experimental allergic glomerulonephritis induced by immunization of rats with renal tubular antigen has been investigated. A single immunization with less than a milligram of a crude renal tubular preparation, probably containing less than 25 microg of the specific nephritogenic antigen, is effective in the induction of this form of chronic membranous glomerulonephritis. In the nephritic kidney autologous nephritogenic tubular antigen is found in the glomerular deposits along with gamma-globulin and complement. When large amounts of antigen are injected during induction of the disease the exogenous immunizing antigen can also be detected in the glomerular deposits. It appears that this disease results from the formation of circulating antibodies capable of reacting with autologous renal tubular antigen(s) and the deposition of these antibodies and antigen(s) plus complement apparently as immune complexes in the glomeruli. This pathogenetic system has been termed an autologous immune complex disease and the resultant glomerulonephritis has been similarly designated.

Auto-immune reactions in ulcerative colitis

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In vitro cytotoxic effects of lymphoid cells from rats with experimental autoimmune nephrosis

A nephrotic syndrome was induced in randomly bred Sprague-Dawley rats by repeated intraperitoneal injections of homologous kidney extract and Freund's complete adjuvant. Cell injury in vitro was measured by estimating the release of radioactivity from damaged target cells labelled with ¹⁴C-thymidine. Various conditions influencing the reproducibility of the isotope method were investigated.

Blood lymphoid cells, lymph node cells and spleen cells from these rats damaged primary monolayer cultures of rat kidney cells after 18 hr incubation. Lymphoid cells from liver sensitized rats were also cytotoxic to rat kidney cells, whereas lymphoid cells from rats injected with other rat tissue extracts (lung or spleen) or given only adjuvant did not react. Primary cultures of rat lung cells were sensitive while cells of a rat liver cell strain were resistant to the cytotoxic action of lymphoid cells from kidney sensitized rats. Sera from nephrotic rats did not damage rat kidney cells under the experimental conditions used here.