The role of T-cells in inflammatory kidney disease

The fundamental role of cell-mediated immunity in inflammatory disease of the kidney has been established for some time. This review focusses on the recent advances in our understanding of the role of T-cells in the pathogenesis both of glomerulonephritis and interstitial nephritis. In particular, the increasing experimental evidence for a functional role for T-cells in promoting disease initiation and progression is examined. The ever increasing variety of T-cell-effector functions and their relevance are also discussed.

Deoxyspergualin inhibits mesangial cell proliferation and major histocompatibility complex class II expression

It has previously been shown that the immunosuppressive drug deoxyspergualin can inhibit renal injury in experimental glomerulonephritis. This study examined whether deoxyspergualin can modulate the mesangial cell response to glomerular injury. Antiglomerular basement membrane glomerulonephritis was induced in primed rats. Groups of five animals were treated with deoxyspergualin (5 mg/kg per day) or saline from Day 0 until being euthanized on Day 1, 7, 14, or 21. Deoxyspergualin treatment significantly inhibited mesangial cell proliferation (proliferating cell nuclear antigen expression) over the disease course as assessed by double immunohistochemistry staining (P < 0.001 versus saline treated) and reduced glomerular major histocompatibility complex (MHC) class II expression. To demonstrate if this was a direct action of deoxyspergualin, an in vitro system was studied. The addition of deoxyspergualin caused a time- and dose-dependent inhibition of [3H]thymidine uptake by cultured rat mesangial cells. Of particular interest was the finding that deoxyspergualin inhibited the de novo cell surface expression of MHC class II antigens after interferon-gamma stimulation. However, deoxyspergualin did not prevent the cytoplasmic accumulation of MHC class II molecules, indicating that the drug interfered with a posttranslational event in MHC class II processing and/or assembly. Deoxyspergualin was not a general inhibitor of mesangial cells, and it had no effect on constitutive or lipopolysaccharide-induced transforming growth factor beta 1 expression. In conclusion, deoxyspergualin has been shown to inhibit the mesangial cell response to glomerular injury. This novel mode of action may provide an additional therapeutic benefit in the treatment of proliferative forms of glomerulonephritis.

Interleukin-1 receptor antagonist halts the progression of established crescentic glomerulonephritis in the rat

The pathogenic role of interleukin-1 (IL-1) in the progression of established rat crescentic glomerulonephritis was investigated by administration of the interleukin-1 receptor antagonist (IL-1ra). Passive accelerated antiglomerular basement membrane (GBM) disease was induced in three groups of six rats. One group was killed on day 7 with no treatment. The other groups received a constant infusion of IL-1ra or saline from day 7 until being killed on day 21. All animals developed moderate glomerular injury, a significant loss of renal function and marked histological damage including crescent formation by day 7. Saline treated animals showed a significant deterioration in these parameters over days 7 to 21. In contrast, animals treated with the IL-1ra over this period showed stabilization of glomerular injury (protein-uria; P < 0.001) and a recovery of normal renal function (creatinine clearance; P < 0.05). Histologically, IL-1ra treatment suppressed glomerular cell proliferation (PCNA expression; P < 0.001) and significantly inhibited crescent formation (P < 0.005), glomerular sclerosis (P < 0.005), tubular atrophy (P < 0.05) and interstitial fibrosis (P < 0.05). A key finding was that IL-1ra treatment not only stopped renal leukocyte accumulation over days 7 to 21 (P < 0.01), but that treatment also suppressed immune activation of the infiltrate (P < 0.01). In conclusion, this study provides direct evidence that IL-1 plays a key role in the progressive/chronic phase of renal injury in experimental crescentic glomerulonephritis and indicates that IL-1ra treatment may be of therapeutic benefit in human rapidly progressive crescentic glomerulonephritis.

ICAM-1 and VCAM-1 in human renal allograft rejection

Light microscopy studies have demonstrated heightened ICAM-1 and VCAM-1 expression in renal allograft rejection in experimental animals and in humans, and administration of ICAM-1 blocking antibodies has been shown to prolong graft survival in nonhuman primates. We used a precise ultrastructural immunogold localization technique to identify the exact sites of expression of ICAM-1 and VCAM-1 in both normal human kidney and in renal allograft rejection. In the normal kidney ICAM-1 is moderately strongly expressed in glomeruli, on the endothelium and parietal epithelium and in the interstitium, on the endothelium of peritubular capillaries, arterioles and small arteries, on fibroblast-like interstitial cells and on the brush border of proximal tubules. In contrast, in normal kidney, VCAM-1 expression is restricted to the parietal epithelium and the basolateral surfaces of a few proximal tubule cells. In allograft rejection, although ICAM-1 expression appears to be increased, its pattern of distribution is similar to that seen in the normal kidney. However, VCAM-I in allograft rejection is widely expressed on the endothelium of peritubular capillaries and arterioles in association with adhesion of mononuclear leukocytes within these vessels. The tubular expression of VCAM-1, although still focal in nature, is increased on the basolateral surfaces in association with lymphocytic infiltration of tubules.(ABSTRACT TRUNCATED AT 250 WORDS)

A novel, simple, reliable, and sensitive method for multiple immunoenzyme staining: use of microwave oven heating to block antibody crossreactivity and retrieve antigens

We report a simple and reliable method for detection of two or more antigens within tissue sections by indirect immunoenzyme staining using mouse monoclonal antibodies (MAbs). This technique involves treating sections with two 5-min microwave (MW) oven heatings between sequential rounds of three-layer immunoenzyme staining (mouse MAb, goat anti-mouse IgG, and mouse PAP or mouse APAAP) and color development. Discrete staining of cell surface, cytoplasmic, and nuclear antigens was evident within individual cells. This technique has a number of advantages over those currently available. First, MW treatment denatures bound antibody molecules, thereby completely blocking crossreactivity between sequential rounds of staining. This allows the use of primary (and other) antibodies raised in the same species and the use of a sensitive three-layer staining method. Second, antigen retrieval after MW treatment markedly increases the sensitivity of cytoplasmic and nuclear antigen detection. Third, inactivation of peroxidase and alkaline phosphatase enzymes present in PAP and APAAP complexes prevents inappropriate color development. Finally, this method can be used in both paraformaldehyde-fixed cryostat sections and formalin-fixed paraffin tissue sections. In conclusion, this is a simple, reliable, and sensitive technique that will be useful in many areas of diagnosis and research.

Control of post-transplant erythrocytosis by enalapril

OBJECTIVE

To assess the erythropoietin response in patients with erythrocytosis after renal transplantation who were treated with enalapril.

PATIENTS

Fourteen patients with stable renal transplants (creatinine clearance, 74.4 +/- 24.6 mL/min) and a packed cell volume of 51% or more over six months and who had no other cause for their erythrocytosis.

METHODS

Patients were treated with enalapril for six months. Serum erythropoietin levels, creatinine clearance and packed cell volume were measured before and during the study; patients were reviewed each month.

RESULTS

All patients had erythropoietin levels inappropriate for their packed cell volume. After six months' therapy with enalapril their mean erythropoietin concentration of 21.3 +/- 5.0 U/L fell to 7.4 +/- 1.3 U/L (P < 0.02) although the concentration increased in two patients. The mean packed cell volume fell from 52.7% +/- 0.5% to 44.4% +/- 1.0% (P < 0.0001). There was no change in renal function.

CONCLUSION

Low-dose enalapril controls post-transplant erythrocytosis, at least in part, by lowering serum erythropoietin levels.

Interstitial activated (IL-2R+) mononuclear cells and Ia antigens in experimental focal glomerulosclerosis

Tubulointerstitial localization of major histocompatibility complex (MHC) class II (Ia) antigens and immune-activated mononuclear cells (IL-2R+) and its suppression by prednisolone (PSL) were studied in a progressive model of focal glomerulosclerosis (FGS) induced by aminonucleoside (AN) and protamine sulfate (PS) given as 4 four day courses in rats. Tissues were prepared for the quantification of leucocytes on days 24, 52 and 80. The numbers of total leucocytes (CD45+), Ia+ cells, monocytes/macrophages, T lymphocytes (CD5+) and IL-2R+ cells (CD25+) were enumerated in immunoperoxidase sections using monoclonal antibodies: OX1, OX6, ED1, OX19 and ART18, respectively. The effects of PSL at a dose of 3 mg/kg body weight, which was begun from day 30, 12 days after the second series of injections, and continued for 50 days, were studied on day 80. There was no significant increase of glomerular T cells or IL-2R+ cells throughout the study. By contrast, each cell group in the interstitium increased in number throughout the disease evolution. Specifically IL-2R+ cells, which were rarely seen before AN + PS injection, were expressed by 5% of total leucocytes on day 80. Ia antigens also increased time-dependently and were found in proximal tubular cells on day 80. PSL treatment suppressed IL-2R and Ia expression in proportion to the decrease of total leucocytes and T cells. These results imply that delayed type hypersensitivity related to the appearance of immune activated T cells (IL-2R+) and MHC class II antigens may play a role in the progression of interstitial lesions and consequent renal dysfunction in a nonimmune-initiated FGS model.

Deoxyspergualin suppresses local macrophage proliferation in rat renal allograft rejection

Deoxyspergualin (DSP) is a potent immunosuppressive drug that is able to both prevent and reverse acute allograft rejection. Although there is good evidence that DSP can inhibit T and B lymphocyte responses, the effect of this drug upon monocyte function is controversial. In the current study, substantial local proliferation of inflammatory macrophages (41.6 +/- 5.5% of ED1+ cells) within acutely rejecting rat renal allografts was identified by expression of the proliferating cell nuclear antigen. Treatment of animals with DSP not only reduced macrophage accumulation within the tissue, but it also significantly inhibited local proliferation of macrophages within the graft (26.4 +/- 5.6% of ED1+ cells, P < 0.05 vs. untreated). This appeared to be, at least in part, a direct effect of DSP upon macrophages since the drug also inhibited growth of 2 monocytic cell lines (RC-2A and U937) in vitro. However, DSP treatment had no effect upon LPS-induced monocyte IL-1 beta, TNF alpha, and IL-6 mRNA and protein production, indicating that this drug is not a general inhibitor of monocyte function. In conclusion, this study has demonstrated that local proliferation of macrophages within the kidney is a prominent feature of acute allograft rejection and that inhibition of this response is one mechanism whereby DSP exerts its potent immunosuppressive actions.

Pulmonary expression of ICAM-1 and LFA-1 in experimental Goodpasture's syndrome

The functional importance of ICAM-1 and its ligands, the beta 2-integrins, in leukocytic accumulation in pulmonary injury has been recently demonstrated in experimental models of lung disease. However, the exact location of these adhesion molecules remains unknown. In the current study we have used immunogold ultrastructural techniques to define the precise location of ICAM-1 in the lung and its interaction with beta 2-integrin expressing leukocytes in the early stages of experimental Goodpasture's (GP) syndrome in the rat. In normal animals there is strong constitutive ICAM-1 expression on the luminal surface of the alveolar epithelium that is confined to type I cells and completely absent from type II cells. Constitutive expression of ICAM-1 on the pulmonary capillary endothelium is comparatively weak. In GP syndrome there is an increase in ICAM-1 expression, which is still confined to the alveolar type I epithelial cells and capillary endothelium. This is associated with an early (1.5 hours) influx of CD18 expressing polymorphonuclear leukocytes, which are seen migrating into alveoli and the pulmonary interstitium. There is a later (6-12 hours) influx of CD11a/CD18 expressing macrophages which are present in the interstitium and in large numbers in the alveolar spaces, where they are very closely apposed to and adherent to the alveolar epithelium. This is the first study to demonstrate the precise ultrastructural location of ICAM-1 in the normal rat lung and in disease. In vivo administered antibody to ICAM-1 gains access to the extravascular sites within the lung, in particular the surface of alveolar type I epithelial cells, and this raises the possibility that beneficial effects of such antibodies may extend beyond their ability to inhibit interactions between leukocytes and endothelial cells.

The adequacy of fragmin as a single bolus dose with reused dialyzers

Thirty-four hemodialysis patients were studied in a crossover fashion to compare the effectiveness of bolus-dose Fragmin (a low molecular weight heparin) with regular heparin usage in hemodialysis. For each anticoagulant, 3 dialyzes were studied for each patient; the first sessions involved a new dialyzer, and the subsequent sessions involved dialyzers reprocessed with peracetic acid. To assess the effectiveness of the anticoagulation regimens, the following were measured: the dialyzer fiber bundle volume and the instantaneous dialyzer clearances for urea (1 h into the second session). In addition, factor Xa levels were measured in 5 patients during the first and second sessions at 0 min, 30 min, and 4 h. Fiber bundle volumes were (in ml) 75.4 +/- 8.8, 73.0 +/- 8.9, and 73.5 +/- 7.6 on first, second, and third uses with Fragmin (p = ns); and 77.8 +/- 9.0, 73.4 +/- 8.1, and 73.8 +/- 8.1 with heparin (p < 0.001 second and third vs. first). Thus, there were no significant differences between Fragmin and heparin. Instantaneous dialyzer clearances were 165.8 +/- 12.6 ml/min with Fragmin and 163.8 +/- 9.8 with heparin (p = ns). Factor Xa levels were 0 predialysis, 0.81 +/- 0.17 U/ml at 30 min on first use, and 0.92 +/- 0.09 U/ml on second use (p = ns); they were 0.51 +/- 0.21 U/ml at 4 h on first use and 0.61 +/- 0.16 U/ml on second use (p = ns). Thus, bolus-dose Fragmin provided similar results to constant infusion heparin and is not deleteriously influenced by reprocessing dialyzers with peracetic acid.

Suppression of experimental glomerulonephritis by the interleukin-1 receptor antagonist: inhibition of intercellular adhesion molecule-1 expression

Interleukin-1 is a proinflammatory cytokine produced in glomerulonephritis. Blocking the action of interleukin-1 by the administration of the interleukin-1 receptor antagonist (IL-1ra) has been shown to prevent renal function impairment, reduce glomerular injury, inhibit leukocyte infiltration, and suppress tubulointerstitial damage in experimental antiglomerular basement membrane disease. A key mechanism in the entry of leukocytes into the kidney is the interaction between the interleukin-1 inducible intercellular adhesion molecule-1 (ICAM-1; CD54) and lymphocyte function-associated antigen-1 (CD11a/CD18). Therefore, this study investigated whether the inhibition of this mechanism was the means by which IL-1ra suppressed leukocyte infiltration in rat accelerated antiglomerular basement membrane glomerulonephritis. Disease was induced in two groups of six rats; animals were treated by constant sc infusion of recombinant human IL-1ra or saline from the initiation of disease until being euthanized 14 days later. In saline-treated animals, there was marked up-regulation of ICAM-1 in the glomerulus and interstitium, In which was associated with leukocyte infiltration. In particular, focal accumulation of CD11a+ and CD18+ cells was apparent in areas of tubulointerstitial damage exhibiting intense ICAM-1 expression. IL-1ra treatment partially reduced glomerular ICAM-1 expression and leukocyte infiltration. However, IL-1ra treatment resulted in a dramatic inhibition of interstitial ICAM-1 expression, interstitial leukocyte infiltration, and tubulointerstitial damage. In conclusion, this study has shown that interleukin-1 is a major inducer of ICAM-1 expression within the renal tubulo-interstitium--a process associated with focal leukocyte infiltration and tubulointerstitial damage.(ABSTRACT TRUNCATED AT 250 WORDS)

The ICAM-1/LFA-1 interaction in glomerular leukocytic accumulation in anti-GBM glomerulonephritis

Recent studies of rat anti-glomerular basement membrane (anti-GBM) disease have demonstrated a functional role for ICAM-1 in the entry of leukocytes into the glomerulus, both in the early polymorphonuclear (PMNL) influx and the more delayed monocyte/macrophage infiltration. In the current study we used immunogold ultrastructural techniques to identify the exact sites of expression of ICAM-1 (CD54) in the glomerulus and the expression of CD11a and CD18 by infiltrating glomerular leukocytes in the first 24 hours of accelerated anti-GBM disease in rats. In normal rats there was constitutive ICAM-1 expression on the luminal surface of the glomerular endothelium and parietal epithelium of Bowman's capsule. In disease ICAM-1 expression was progressively increased over 24 hours on a thickened, reactive glomerular endothelium, being most prominent on endothelium adjacent to the mesangial stalks. Mesangial cells demonstrated surface ICAM-1 expression only in focal areas of superficial mesangiolysis. PMNL, the predominant glomerular inflammatory cell in the first 12 hours of accelerated anti-GBM GN, expressed abundant surface CD18 which was present at the sites of adhesion of the PMNL to the glomerular endothelium. In contrast PMNL expressed only very sparse surface CD11a, suggesting that another beta 2 integrin, Mac-1, which shares a common beta chain with LFA-1 may be the more important PMNL counter receptor for ICAM-1 in the glomerulus. Glomerular monocyte/macrophage infiltration became evident within glomerular capillary loops and the mesangium from 6 to 24 hours. These adherent and migrating leukocytes expressed abundant surface CD11a and moderate CD18 particularly at their sites of adhesion to glomerular endothelium.(ABSTRACT TRUNCATED AT 250 WORDS)

Suppression of pulmonary injury in experimental 'Goodpasture's syndrome' by deoxyspergualin (DSP)

DSP is a potent immunosuppressive drug which can prevent allograft rejection and suppress acute rejection episodes. In this study, the ability of DSP to suppress pulmonary injury in experimental Goodpasture's syndrome was investigated. Passive accelerated anti-glomerular basement membrane (GBM) disease was induced in rats by priming with rabbit IgG, followed 5 days later by injection of rabbit anti-GBM serum (day 0). Groups of five animals were treated with DSP (5 mg/kg intraperitoneally per day) or saline (untreated) from day 0 until being killed on days 1, 7, 14 or 21. At day 1, both DSP-treated and untreated animals exhibited similar pulmonary haemorrhage, oedema, and prominent perivascular leucocyte infiltration. Untreated animals subsequently developed severe widespread pulmonary damage including granulomatous lesions and extensive fibrosis, which correlated with infiltration of macrophages and immune-activated (IL-2R+) mononuclear cells (P < 0.01). Tumour necrosis factor-alpha (TNF-alpha), a known mediator of acute lung damage, was produced by pulmonary mononuclear cells throughout the experimental course. In contrast, DSP treatment resolved pulmonary haemorrhage, prevented the appearance of granulomatous lesions, and resulted in a histologically normal lung structure by day 21. This improvement was associated with a marked suppression of macrophage infiltration (P < 0.001 versus untreated), accumulation of immune activated (IL-2R+) mononuclear cells (P < 0.01 versus untreated), and TNF-alpha production (P < 0.05 versus untreated). DSP treatment also suppressed the deposition of rat anti-rabbit IgG immunoglobulin and C3 along the alveolar basement membrane (P < 0.05 versus untreated). In conclusion, DSP suppressed pulmonary injury in accelerated anti-GBM disease by acting on the local cellular immune response and the systemic humoral immune response. Further studies are warranted to determine whether this could be a useful drug for the treatment of Goodpasture's syndrome in humans.

A sensitive method of non-radioactive in situ hybridization for mRNA localization within human renal biopsy specimens: use of digoxigenin labeled oligonucleotides

A sensitive method of non-radioactive in situ hybridization using digoxigenin-labeled oligonucleotides is described for the detection of mRNA within human renal biopsy specimens. Although non-radioactive in situ hybridization typically has the drawback of low sensitivity, we increased the sensitivity of this method, providing a practical alternative to the use of radiolabelled probes. The four main points are: 1) assessment of the efficiency of labeling, 2) optimization of the probe concentration for hybridization, 3) requirement of deproteinization of tissues with HCl and proteinase K, and 4) the use of a four-layer immunoperoxidase staining system. This technique was found to clearly localize individual mRNA positive cells within cryostat tissue sections. A variety of controls including sense probes, excess unlabeled anti-sense probes, and RNase-treatment demonstrated the specificity of the technique. This improved method is a powerful technique for detecting mRNA within human renal tissue and will be most useful in the study of gene expression in the pathogenesis of renal diseases.

Macrophages in renal injury

There is good evidence from experimental studies that glomerular macrophages are important in acute renal injury and an increasing acceptance that they also play a role in chronic glomerular injury by stimulating mesangial cell proliferation and glomerulosclerosis. However, it is now evident that the contribution of macrophages and T cells within the interstitium must be taken into account. Indeed, if it is proved that progressive renal injury occurs via interstitial DTH mechanisms, regardless of the nature of the initial glomerular insult, then such mechanisms may provide a suitable target for the development of novel therapeutic strategies.

ICAM-1 directs migration and localization of interstitial leukocytes in experimental glomerulonephritis

Recent studies of rat anti-GBM disease have demonstrated a functional role of the ICAM-1/LFA-1 interaction in the entry of leukocytes into the glomerulus and an association between interstitial ICAM-1 expression, leukocyte infiltration and tubulointerstitial damage. In the current study, we used immunogold ultrastructural techniques to identify ICAM-1/LFA-1 interactions in the initiation of interstitial leukocyte infiltration during the first 24 hours of rat accelerated anti-GBM disease. In normal rats, there was weak constitutive ICAM-1 expression in the interstitium: on the endothelial luminal surface of interstitial capillaries, venules and arterioles, on the entire surface of interstitial fibroblast-like cells and confined to the brush border of proximal tubules. As early as 1.5 hours after injection of anti-GBM serum, there was a marked increase in the intensity of ICAM-1 expression, most notably on capillary endothelium, fibroblast-like cells and brush borders of proximal tubules, particularly in the periglomerular/perihilar areas. Mononuclear leukocytes exhibiting strong surface LFA-1 (CD11a and CD18) expression were seen adherent to the endothelium of interstitial capillaries, with ICAM-1 and LFA-1 antigens present at sites of contact. In addition, mononuclear cells migrating into the interstitium showed areas of close apposition to interstitial fibroblast-like cells, and here ICAM-1 and LFA-1 expression were also prominent at the sites of contact. This is the first study to demonstrate sites of ICAM-1/LFA-1 interaction in mononuclear cell migration and localization in glomerulonephritis. The results suggest that up-regulation of periglomerular/peritubular capillary ICAM-1 expression is important for mononuclear cell entry into the interstitium, while interaction with fibroblast-like cells may facilitate movement and subsequent focal accumulation of mononuclear cells at sites within the interstitium.

Regulation of human renal adenocarcinoma cell growth by retinoic acid and its interactions with epidermal growth factor

Retinoic acid (RA) is a natural derivative of vitamin A which regulates the growth and differentiation of epithelia. We have previously proposed that RA participates in compensatory kidney growth and reported that RA inhibits rat mesangial cell growth. This paper describes the effects of RA on a human renal adenocarcinoma cell line (PAD) under different growth conditions, and its interactions with epidermal growth factor (EGF). PAD cells were shown to express RA receptors alpha and beta by Northern blot analysis. In serum free cultures, addition of RA (10(-7) M) markedly increased thymidine incorporation by PAD cells (155 +/- 7% mean +/- SE vs. control in 6 separate experiments; P < 0.0001). RA also caused a significant increase in thymidine incorporation by PAD cells under conditions of rapid growth in serum supplemented medium (115 +/- 2% vs. control; P < 0.001). RA by itself was unable to reverse contact inhibition of PAD cell growth (NS vs. control), but it synergistically enhanced the mitogenic effect of EGF on confluent monolayers (110 +/- 0.6% vs. EGF alone; P < 0.05). Northern blot analysis demonstrated that PAD cells express EGF receptor mRNA, and this was not significantly modified by the addition of RA. Growth arrested (serum starved) PAD cells expressed RAR-alpha mRNA which was upregulated eightfold at three hours following the addition of 10% FCS. Thus, our data show that RA is directly mitogenic for serum starved human renal adenocarcinoma cells and that it exerts complex modulation of cell growth in the presence of EGF and serum components.

Investigation of hematuria at a printing company

An investigation was undertaken at a printing company into an apparently high prevalence of trace dipstick hematuria discovered during routine medical examinations. In both the printing employees (n = 225) and a control group (n = 118) from other industries, the prevalence of hematuria exceeded that described in most previous reports (31% and 25%, respectively, using the criterion of > 12 glomerular red cells or > 2 nonglomerular red cells/microliter of urine). No focus of abnormality was identified within the printing plant and no association was identified between reported exposure to potentially toxic substances and the degree of hematuria. An occupational hygiene inspection and medical follow-up of selected workers did not reveal any significant abnormalities. The limitations of available information concerning "normal" urinalysis results suggests that hematuria may not be a useful test for the screening of occupational groups at risk of bladder cancer.

Expression of VCAM-1 and E-selectin in an in vivo model of endothelial activation

Vascular cell adhesion molecule 1 (VCAM-1) and E-selectin (or endothelial-leukocyte adhesion molecule 1) are inducible endothelial cell adhesion molecules that play a role in the recruitment of leukocytes into sites of inflammation. Information about the spatial and temporal pattern of induced expression of these leukocyte adhesion molecules in vivo is limited. This study reports the expression profile of VCAM-1 and E-selectin in various mouse tissues after lipopolysaccharide administration. Using rat complementary DNA probes for VCAM-1 and E-selectin, Northern blot analysis showed a marked increase in transcript levels for both adhesion molecules in lung, heart, and kidney. Maximal transcript levels for both VCAM-1 and E-selectin were observed at 3-6 hours and declined to low, constitutive levels of expression at 48 hours. Consistent with the Northern blot results, immunoperoxidase analysis revealed focal endothelial cell expression of VCAM-1 in control animals. Following lipopolysaccharide administration, VCAM-1 expression increased dramatically in all vascular beds examined, although the response was heterogeneous. Widespread induced expression of VCAM-1 on cells other than vascular endothelium was not seen. Neither basal nor induced expression correlated with leukocyte adhesion. Signals other than the expression of endothelial leukocyte adhesion molecules are required in vivo for leukocyte infiltration in this murine model of systemic endothelial activation.

Suppression of experimental crescentic glomerulonephritis by deoxyspergualin

Deoxyspergualin is an immunosuppressive drug which is effective in both preventing allograft rejection and suppressing steroid-resistant acute rejection. This study was designed to determine whether deoxyspergualin could suppress the development of rapidly progressive crescentic glomerulonephritis in antigen-primed animals. Accelerated anti-glomerular basement membrane (GBM) glomerulonephritis was induced by priming rats with rabbit immunoglobulin G (IgG), followed 5 days later by an injection of rabbit anti-rat GBM serum (day 0). Groups of five animals were treated with deoxyspergualin (5 mg/kg.day) or saline by daily ip injection from day 0 until euthanasia on days 1, 7, 14, or 21. Deoxyspergualin treatment resulted in a significant suppression of renal disease. Compared with saline-treated controls, deoxyspergualin treatment reduced proteinuria, resolved hematuria, and completely prevented a fall in creatinine clearance. Deposition of rabbit IgG along the GBM was unaffected by deoxyspergualin treatment, but glomerular deposition of rat IgG and C3 was significantly reduced from day 14 onwards, which was associated with a significant reduction of circulating rat anti-rabbit IgG. Deoxyspergualin treatment also produced a dramatic improvement in renal histology. Glomerular necrosis, fibrosis, and crescent formation were markedly suppressed, whereas tubulointerstitial lesions were completely prevented. This was associated with a marked suppression of mononuclear cell infiltration and activation. In the glomerulus, macrophage infiltration was suppressed by approximately 50%, whereas accumulation of macrophages and immune-activated (interleukin-2 receptor) T cells within the interstitium was almost completely abrogated by deoxyspergualin treatment. In conclusion, deoxyspergualin was found to be effective in suppressing the development of experimental crescentic glomerulonephritis in antigen-primed animals by acting on both the local cell-mediated response within the kidney and the systemic humoral immune response. Further work is warranted to determine whether this could be a useful drug for the treatment of human proliferative glomerulonephritis.

Trafficking of inflammatory macrophages from the kidney to draining lymph nodes during experimental glomerulonephritis

Macrophage accumulation within the glomerulus and renal interstitium is a prominent feature of most forms of glomerulonephritis, but the fate of these inflammatory cells is unknown. Macrophage trafficking to the draining kidney lymph nodes (KLN) was assessed in a detailed kinetic analysis of accelerated antiglomerular basement membrane (GBM) disease in the rat. Leucocytes draining to KLN via lymphatic vessels were identified within the marginal sinus by MoAb labelling of tissue sections. In anti-GBM disease, there was a significant increase in the weight of the KLN due to both lymphoproliferation within the nodes and increased lymphatic drainage from the inflamed kidney, as evidenced by prominent dilation of the marginal sinus and increased numbers of cells within the sinus. In non-inflamed lymph nodes, few ED1+ macrophages were present within the marginal sinus (3.0 +/- 0.6/100 nucleated cells). However, in anti-GBM disease, macrophages became the major cell type within the dilated marginal sinus of the KLN, as shown by labelling with ED1, ED2 and ED3 MoAbs, peaking at 74 +/- 2.6 ED1+ cells/100 nucleated cells at day 14. These changes were not simply due to systemic antigen administration, since in the axillary lymph node (ALN) there was no obvious dilation of the marginal sinus and macrophages accounted for a maximum of only 15 +/- 4.6 ED1+ cells/100 nucleated cells. In conclusion, this study provides indirect evidence that there is significant trafficking of the renal macrophage infiltrate to the KLN during experimental glomerulonephritis. This may be a mechanism whereby nephritogenic antigens, released as a consequence of the local inflammatory response, may be presented to T and B lymphocytes within lymph nodes, resulting in the amplification of the immune response in glomerulonephritis.

Immune events in lymphoid tissues during experimental glomerulonephritis

To investigate immune events within lymphoid tissues and their role in relation to glomerular disease, systemic lymphoid tissues from rats with accelerated experimental anti-GBM glomerulonephritis or with primed serum sickness glomerulopathy were studied. Following disease induction, changes in leukocytic populations within lymphoid tissues were analysed over a 28 day time course by immunoperoxidase labelling with monoclonal antibodies. In anti-GBM glomerulonephritis there was rapid and severe renal injury and pulmonary hemorrhage (Good-pasture's syndrome). In these rats, antigen (rabbit IgG) was deposited on the GBM and within germinal centres of lymphoid tissues. From day 3 onwards, there was a significant increase in the number of T cells, presumably CD4+ T helper cells, present within enlarged germinal centres of kidney draining lymph nodes, axillary lymph nodes and spleen (p < 0.05) which peaked at day 14 (up to 28% of total cells) when there was intense deposition of rat IgG and C3 on the GBM. Similarly, increased numbers of ED1+ macrophages were evident in both germinal centres and T cell areas (paracortex and periarteriolar lymphoid sheath). Notably, the appearance of IL-2R expression in germinal centres and T cell areas was apparent from day 7 onwards. This was the time when widespread renal interstitial infiltration, cellular immune activation and severe renal functional and histological injury developed. In addition, antigen deposited in germinal centres was found to be associated with CD4+, CD5-, ED1- cells, most probably antigen presenting dendritic cells. In contrast, in acute serum sickness there was no antigen deposited in germinal centres and only mild renal injury and minor changes within lymphoid tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

Interferon-gamma stimulates the secretion of IL-1, but not of IL-6, by glomerular mesangial cells

IL-1 activity in culture supernatant and cell lysate from rat mesangial cells stimulated with interferon-gamma (IFN-gamma) was measured by a thymocyte proliferation assay. While IFN-gamma alone had no effect on the secretion or the intracellular pool of IL-1, the enhancement by IFN-gamma of IL-1 secretion in response to lipopolysaccharide (LPS) was observed. The stimulatory effect of culture supernatant on thymocyte proliferation was abrogated by preincubation with the anti-IL-1 antibody. At least 4-h incubation with IFN-gamma and LPS was required to detect enhancing effect of IFN-gamma. The addition of as little as 1 U/ml IFN-gamma significantly increased IL-1 secretion in the presence of 10 micrograms/ml LPS. The IL-6 activity in culture supernatants was determined by measurement of thymidine uptake in mouse IL-6-dependent cell line (MH60.BSF2). Mesangial cells secreted IL-6 in culture supernatant without additional stimuli and LPS distinctly increased it as described previously. However, in contrast to IL-1 production, no effect of IFN-gamma on IL-6 secretion was observed in the presence or absence of LPS. Moreover, we determined whether enhanced IL-1 release is associated with Ia expression on mesangial cells. IFN-gamma alone and the combination with LPS induced marked expression of Ia antigen, whereas LPS alone did not. We conclude that IFN-gamma stimulates the production of IL-1, but not IL-6, by mesangial cells and suggest an important role of IFN-gamma in the pathogenesis of glomerulonephritis by regulating the mesangial production of IL-1 and the accessory cell function of mesangial cells.