concanavalin-a and Glomerulonephritis--IGA

TJN-331 is an inhibitor of transforming growth factor β1 (TGF-β1) production that has similar structural features to the natural product acteoside. This study was performed to examine the antinephritic effects of TJN-331 in a mouse model of experimental IgA nephropathy.. IgA nephropathy was induced in ddY mice by oral administration of bovine γ globulin, followed by reticuloendothelial blocking by colloidal carbon injection and heminephrectomy. Effects of TJN-331 were examined over oral administration periods from 10 to 15 weeks after the third colloidal carbon injection. Intravenous administration of a TGF-β1-neutralizing antibody was used to investigate the role of TGF-β1 in IgA nephropathy.. Administration of TJN-331 or captopril prevented elevation of serum creatinine. Histopathological examination after both experimental periods showed that TJN-331 inhibited increases in the mesangial matrix index and the number of nuclei per glomerular cross-section, compared with in untreated ddY mice with IgA nephropathy. TJN-331 prevented increase in glomerular TGF-β1 staining without affecting IgA. In the in vitro study, TJN-331 prevented total TGF-β1 production from splenocytes stimulated with concanavalin A. A neutralizing antibody against TGF-β1 prevented increase in the mesangial matrix index and the number of glomerular cells per cross-sectional area.. These results suggest that TJN-331 is effective against IgA nephropathy in ddY mice and acts via suppression of TGF-β1 production in glomeruli.

Topics: Acrylamides; Animals; Concanavalin A; Creatinine; Disease Models, Animal; Glomerular Mesangium; Glomerulonephritis, IGA; Kidney Glomerulus; Mice; Mice, Inbred Strains; Nephrectomy; Pyridines; Spleen; Transforming Growth Factor beta1

A lymphokine, the vascular permeability factor (VPF), which increases vascular permeability, has been characterized in minimal-change nephrotic syndrome (MCNS). Transforming growth factor-beta (TGF-beta) is an immunosuppressive cytokine that inhibits proliferation, cytokine production, and cytotoxic activity of T cells and natural killer cells. We, therefore, investigated the effects of TGF-beta1 on the release of VPF by peripheral blood T cells from MCNS patients. The aim of our study was to determine the in vitro immunosuppressive capacity of TGF-beta1 in patients with MCNS.. To further test the effect of TGF-beta1 on concanavalin A (Con A)-induced VPF release, normal and MCNS T cells were stimulated with 5 microg/ml of Con A in the presence or absence of TGF-beta1, and the culture supernatants were tested for the presence of VPF by the method of Lagrue et al. The disease controls included 16 patients with IgA nephropathy.. Significantly increased spontaneous and Con A-stimulated secretion of VPF was detected in T-cell cultures of MCNS patients with the nephrotic syndrome as compared with those of normal controls. Addition of TGF-beta1 to these cultures inhibited the release of VPF in a dose-dependent manner. The effect of TGF-beta1 on the release of VPF was specific, since a reversion was obtained with a neutralizing monoclonal antibody to human TGF-beta1.. Together, our data demonstrate that TGF-beta1 antagonizes the ability of T cells to release VPF, and suggest a role of TGF-beta1 in the pathophysiology of VPF in vitro.

Topics: Adult; Capillary Permeability; Case-Control Studies; Concanavalin A; Dose-Response Relationship, Drug; Endothelial Growth Factors; Female; Glomerulonephritis, IGA; Glucocorticoids; Humans; In Vitro Techniques; Lymphokines; Male; Nephrosis, Lipoid; Prednisone; T-Lymphocytes; Transforming Growth Factor beta; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

Increased production of a vascular permeability factor (VPF) from peripheral blood mononuclear cells (PBMC) in patients with minimal-change nephrotic syndrome (MCNS) has been reported. Interleukin-4 (IL-4) and interleukin-10 (IL-10), both produced by T-helper type-2 cells, are cytokines with the capacity to downregulate proinflammatory responses. To gain insight into the immunoregulatory properties of these cytokines, we analyzed the effects of recombinant human IL-4 and IL-10 on VPF release in MCNS patients. In the present study we show that the regulatory cytokines IL-4 and IL-10 are potent inhibitors of the VPF activity of concanavalin A-activated MCNS PBMC. Each cytokine was found to suppress VPF release in a dose-dependent manner. Moreover, when used at suboptimal concentrations, a combination of the two cytokines resulted in enhanced suppression of VPF release. Neutralization of endogenously produced IL-4 and IL-10 by both anti-IL-4 and anti-IL-10 antibodies resulted in an increased release of VPF. These data demonstrate that IL-4 acts in concert with IL-10 to inhibit VPF release and suggest that they are effective biologic regulators of the VPF responses in vitro.

Topics: Adolescent; Adult; Concanavalin A; Dose-Response Relationship, Drug; Down-Regulation; Endothelial Growth Factors; Female; Glomerulonephritis, IGA; Humans; Interleukin-10; Interleukin-4; Leukocytes, Mononuclear; Lymphokines; Male; Nephrosis, Lipoid; Statistics, Nonparametric; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

The characteristic function of interleukin (IL)-15 appears to be its ability to mimic the stimulatory action of IL-2 on lymphocytes by utilizing part of the IL-2 receptor complex. To gain insight into the immunoregulatory properties of this cytokine in patients with minimal-change nephrotic syndrome (MCNS), we analyzed effects of IL-15 on vascular permeability factor (VPF) release in vitro. Peripheral blood mononuclear cells (PBMC) were isolated from 16 patients with MCNS, 16 patients with IgA nephropathy (IgAN) and 16 healthy controls. Cells were stimulated with concanavalin A (Con A) and the VPF was assessed using the method of Lagrue with minor modifications. PBMC secreted significantly increased amounts of VPF under stimulation with Con A in patients with MCNS and IgAN patients with the nephrotic syndrome as compared with normal controls. Here we have demonstrated, for the first time, that addition of IL-15 to PBMC obtained from nephrotic patients as well as from normal controls increased Con A-induced release of VPF by 250%. This stimulatory effect was found highly significant and was dose-dependent. The effect of IL-15 on the secretion of VPF was specific, since a complete reversion was obtained with a neutralizing antibody to human IL-15. Our findings reveal that IL-15 has the potential to function as an immunoregulatory molecule of PBMC VPF release. In addition, IL-15 had similar effects to IL-2 in terms of its capacity to upregulate VPF release. Taken together, our data emphasize a positive regulatory role for IL-15 in inducing the release of VPF when present at optimal levels. Therefore, IL-15 antagonists may provide a basis for immune intervention in the pathophysiology of VPF.

Topics: Adult; Cells, Cultured; Concanavalin A; Endothelial Growth Factors; Female; Glomerulonephritis, IGA; Humans; Interleukin-15; Interleukin-2; Kidney; Kinetics; Lymphocyte Activation; Lymphocytes; Lymphokines; Male; Nephrotic Syndrome; Reference Values; Steroids; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

The vascular permeability factor (VPF) is a lymphokine that has been shown to play a role in lipoid nephrosis (LN). Prior studies have shown that interleukin (IL) 12 promotes T helper type 1 differentiation and enhances production of T helper type 1 cytokines such as gamma interferon and IL-2. We, therefore, investigated the effects of recombinant human IL-12 on the release of VPF by peripheral blood mononuclear cells (PBMC) from LN patients. The VPF activity was measured according to the method of Ovary, with minor modifications. The goal of the present study was to examine the importance of IL-12 in concanavalin A induced VPF release in vitro. The levels of VPF were measured in a group of healthy subjects, LN patients with or without the nephrotic syndrome, and patients suffering from IgA nephropathy. There was a significantly increased concanavalin A induced release of VPF in LN and IgA nephropathy patients with nephrotic syndrome as compared with normal controls. Recombinant human IL-12 was found to enhance VPF release in a dose-dependent manner. Neutralization of endogenously produced IL-12 by anti-IL-12 antibody resulted in a decreased release of VPF by LN PBMC. These data indicate that endogenously produced IL-12 functions as a costimulatory molecule in vitro. Our data show that IL-12 can upregulate the release of VPF derived from LN PBMC. Thus IL-12 might be a potent adjuvant for inducing VPF. Therefore, IL-12 antagonists may interfere with newly initiated and ongoing VPF release associated with nephrotic syndrome.

Topics: Adolescent; Adult; Antibodies; Concanavalin A; Endothelial Growth Factors; Female; Glomerulonephritis, IGA; Humans; Interleukin-12; Leukocytes, Mononuclear; Lymphokines; Male; Nephrosis, Lipoid; Neutralization Tests; Recombinant Proteins; Steroids; Stimulation, Chemical; Up-Regulation; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

Topics: Animals; Aorta; Cell Adhesion Molecules; Colchicine; Concanavalin A; Glomerulonephritis, IGA; Immunoglobulin A; Injections, Intra-Arterial; Microtubules; Rats; Rats, Inbred Lew

Topics: Aging; Animals; Autoantibodies; Concanavalin A; Cyclosporine; DNA; Female; Glomerulonephritis, IGA; Lymphocyte Activation; Mice; Mice, Inbred Strains; Spleen; Tacrolimus

The perfusion of polymeric IgA (pIgA)--or secretory IgA (sIgA)--Concanavalin A (ConA) non-immune complexes (apparent Mol.Wt greater than 10(3) Kd) into the aorta of rats led to a dose-dependent and a mannose-dependent deposition of both IgA and lectin into the glomeruli. Rats injected with amounts of those complexes as low as 500 micrograms developed, one hour later, a focal and segmental proliferative glomerulonephritis characterized by: a) the deposition in the mesangial area of most glomeruli of injected complexes and of rat C3; b) small areas of fibrinoïd necrosis in 10 to 15% of glomeruli, confined to the periphery of a single lobule of the tuft; c) a segmental infiltration of those glomeruli by polymorphonuclear leucocytes, mononuclear phagocytes and platelets; d) a hyperactive aspect of mesangial cells; e) the presence of red blood cells in tubular lumens. By contrast, no glomerular lesions were obvious in rats similarly injected either with monomeric IgA (mIgA)-ConA, pIgA-peanut agglutinin (PNA) or sIgA-PNA complexes or with heat-aggregated pIgA or mIgA. The data indicate that preformed polymeric IgA-ConA complexes can specifically bind to glomerular structures in vivo and locally trigger, as antigen-antibody complexes, an acute inflammatory reaction resulting in glomerular lesions similar to those observed in Henoch-Schönlein purpura nephritis.

Topics: Acute Disease; Animals; Concanavalin A; Disease Models, Animal; Female; Fluorescent Antibody Technique; Glomerulonephritis, IGA; Immunoglobulin A; Kidney Glomerulus; Microscopy, Electron; Rats; Rats, Inbred Strains

Topics: Adolescent; Adult; Antigen-Antibody Complex; B-Lymphocytes; Child; Concanavalin A; Glomerulonephritis, IGA; Humans; Immunoglobulin A; Immunoglobulin G; Immunoglobulin M; Pokeweed Mitogens; T-Lymphocytes

Spontaneous in vitro IgA synthesis by peripheral blood mononuclear cells (PBMC) of patients with IgA nephropathy was elevated; 419 +/- 71 ng/10(6) cells (Mean +/- SEM) compared with controls; 217 +/- 35 (P less than 0.02). Pokeweed mitogen (PWM) stimulated IgA synthesis was also elevated in patients; 4326 +/- 1140 ng/10(6) cells (Mean +/- SEM) versus 1458 +/- 406 (P less than 0.02) but the PWM stimulation index for patients did not differ significantly from that of the controls. Concanavalin A (Con A) suppression of PWM stimulated IgA synthesis resulted in the generation of similar quantities of IgA by PBMC from both patients and controls but the percentage suppression was significantly elevated in patients; 87 +/- 5 (Mean +/- SEM) versus 58 +/- 10 (P less than 0.05). Synthesis of IgG and IgM followed the same pattern as that described for IgA. T and B cells from patients and controls were cultured alone and in various co-culture permutations. Enriched B cells of patients demonstrated a selectively increased capacity for IgA production; 266 +/- 106 ng/5 X 10(5) cells (Mean +/- SEM) compared with controls; 42 +/- 9 (P less than 0.01) and this parameter correlated significantly with serum IgA concentrations (R = 0.77, P less than 0.05). Overall analysis of co-culture data showed no significant difference between the influences of autologous, control or patient T cells on immunoglobulin synthesis by normal B cells. Autolymphocytotoxic antibodies were not detected and, compared with controls, patient sera had no differential effect on numbers of IgA producing cells generated in culture.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adolescent; Adult; Aged; B-Lymphocytes; Cells, Cultured; Concanavalin A; Culture Media; Enzyme-Linked Immunosorbent Assay; Female; Glomerulonephritis, IGA; Humans; Immunoglobulin A; Lymphocyte Activation; Male; Middle Aged; Monocytes; Pokeweed Mitogens; T-Lymphocytes

Patients with IgA nephropathy have elevated serum levels of polymeric IgA, probably due to an increase in their synthesis by peripheral blood mononuclear cells, and specific abnormalities in the immunoregulation of IgA. The existence of familial cases of IgA nephropathy, as well as the published association of this nephropathy with some antigens of the HLA system, decided us to test the hypothesis that some of these alterations might be genetically controlled. For this reason we studied some of these immunological assays in 25 first-degree relatives of 7 patients with IgA nephropathy and 22 control subjects matched for age and sex. An abnormal immunological assay was found in at least 1 relative of all families examined. Thus, 16 of 25 relatives had a significant increase in the percentage of polymeric IgA-producing cells after 7 days of culture in the presence of pokeweed mitogen. Some derangement in the concanavalin A generation of specific IgA suppressor cells was found in 11 out of 25 relatives. These results are, though in lower frequency, similar to those seen in patients and suggest that the IgA-immunological abnormalities observed are genetic markers, even if they cannot by themselves explain the pathogenesis of the IgA nephropathy. The absence of IgA immune complexes seen in relatives as well as their high prevalence in patients suggest that in predisposed subjects other factors (genetic or not) are required for the development of IgA nephropathy.

Topics: Adolescent; Adult; Antibodies, Monoclonal; Child; Concanavalin A; Family; Female; Glomerulonephritis, IGA; HLA Antigens; Humans; Immunoglobulin A; Immunoglobulin Fragments; Immunoglobulin G; Immunoglobulin M; Male; Middle Aged; T-Lymphocytes; T-Lymphocytes, Helper-Inducer; T-Lymphocytes, Regulatory; Ultracentrifugation