Induction of different types of glomerulonephritis by monoclonal antibodies derived from an MRL/lpr lupus mouse.

MRL/Mp-lpr/lpr(MRL/lpr) lupus mice develop glomerulonephritis in which the histopathological manifestations of the disease are characterized by diffuse cell-proliferative, crescentic, and/or wire loop-like lesions, resembling those of human lupus nephritis. Although these lesions are thought to be mediated by antibodies, little data is available to explain these regular variations in glomerular lesions induced by antibodies at the monoclonal level. We studied glomerular lesions of normal or severe combined immunodeficient mice injected with nephritogenic immunoglobulin G3-producing hybridoma clones (2B11.3 and 7B6.8), which we previously established from an unmanipulated MRL/lpr mouse. Both clones caused increased serum levels of immunoglobulin G3 with identical patterns over time and both induced glomerular deposits of immunoglobulin G3 and C3. However, 2B11.3 and 7B6.8 induced glomerular lesions that differed in their histopathological manifestations. The 2B11.3 clone generated cell-proliferative lesions associated with marked Mac-2-positive macrophage infiltrates, but the 7B6.8 clone induced lesions characterized by subendothelial hyaline deposits resembling wire loops. The latter was not associated with significant inflammatory cell infiltrates at any point throughout the progression of the lesion. Thus, our findings suggest that the histopathological variation in glomerulonephritis seen in MRL/lpr mice results from clonally expanded B cell clones that produce nephritogenic antibodies with different pathogenic potencies.     

Augmentation of osteopontin expression in renal tubuli is independent of a histopathological type of glomerular lesions in mouse lupus nephritis

Augmentation of osteopontin (OPN) expression in renal tubuli is often observed in lupus nephritis. To investigate whether this might depend on histopathological type of glomerular lesions, comparative studies of the distribution and levels of OPN expression in kidneys were performed by in situ hybridization and real-time polymerase chain reaction in mouse lupus nephritis manifesting inflammatory (endocapillary proliferative) and deposit (wire loop) types of glomerular lesions. These glomerular lesions were developed in C.B-17/Inc-scid/scid mice by injection of IgG3 antibody producing hybridoma clones, 2B11.3 and 7B6.8, respectively, which are derived from an MRL/Mp-lpr/lpr (MRL/lpr) lupus mouse. Both clones significantly augmented OPN expression in renal tubuli, but a non-nephritogenic IgG3 clone, 1G3, derived from the same MRL/lpr mouse, did not. The OPN augmentation was prominent in the renal cortex and the inner stripe of the outer medulla. These results indicate that OPN augmentation in renal tubuli is not associated with a histopathological type of glomerular lesion in lupus nephritis, at least not with an inflammatory or a deposit type.     

Anti-ribosomal-P antibodies accelerate lupus glomerulonephritis and induce lupus nephritis in naïve mice

BackgroundLupus nephritis is known to be associated with several antibodies including autoantibodies that target the DNA, C1q and histone, α-actinin, and the nucleosome. In addition, circulating anti-phosphoribosomal protein antibodies (anti-Ribos.P) were found to be associated with lupus nephritis.Study objectiveWe have assessed the direct role of anti-Ribos.P in the development of glomerulonephritis in-vitro and in animal models.Study designNZBxW/F1 lupus prone mice were immunized with recombinant Ribos.P0 (rRibos.P). Evaluation of renal disease included mice evaluation for proteinuria and histologic analysis of the kidneys. Anti-Ribos.P monoclonal Ab was prepared from the rRibos.P immunized NZBxW/F1 mice by hybridoma technology. MAPKs expression was analyzed by MAPKs protein array and confirmed by real-time PCR and western blot. To elucidate whether anti-Ribos.P induce glomerulonephritis, naïve C3H mice were immunized with recombinant rRibos.P and the glomerulonephritis was followed up as described above.ResultsThe immunized NZBxW/F1 lupus prone mice developed anti-Ribos.P which was cross reactive with Sm and not dsDNA. The mice developed accelerated glomerulonephritis manifested by early proteinuria and immunoglobulin deposites in the mesangium of the kidneys. Anti-Ribos.P deposited in the glomerular mesangium were eluted from the kidney. The Ribos.P immunized naïve C3H/Hen mice developed glomerulonephritis manifested by circulating autoantibodies directed to Ribos.P, dsDNA and Sm. The anti Ribos.P were cross reactive with Sm but not with dsDNA, and were deposited in the glomeruli. Interestingly these mice developed alopecia. In vitro. Primary mesangial cells exposed to mouse anti-Ribos.P mAb originated from the immunized lupus mice and to human anti-Ribos.P Abs, induced activation of mesangial cells via p38α, JNK, AKT and HSP27 MAPKs expression pathway.ConclusionsOur data show for the first time that anti-Ribos.P are nephritogenic autoantibodies, as illustrated by in-vitro and in-vivo experiments: a) They accelerate the development of glomerulonephritis in lupus prone mice; b) They induce nephritis in naïve mice. c) Anti-Ribos.P Abs trigger MAPKs expression in primary mesangial cells. These data contribute a direct mechanistic link between anti-Ribos.P and nephritis in lupus mice.     

Delivering PD-1 inhibitory signal concomitant with blocking ICOS co-stimulation suppresses lupus-like syndrome in autoimmune BXSB mice

BXSB mice spontaneously develop an autoimmune syndrome characterized by hypergammaglobulinemia, autoantibody production, and the development of fatal glomerulonephritis that closely resembles systemic lupus erythematosus (SLE) in humans. While blocking positive T cell co-stimulation has shown effectiveness in preventing the onset of murine lupus, deliberate delivering negative co-stimulation to halt unwanted T and B cell activation has not been tested. We developed a recombinant adenovirus containing the full-length mouse PD-L1 gene (Ad.PD-L1) to engage the immunoinhibitory receptor PD-1 on activated lymphocytes to prevent lupus nephritis in BXSB mice. This strategy was further reinforced by concomitant injection of anti-ICOSL(B7h) mAb to block ICOS-mediated co-stimulation. The combined therapy dramatically delayed the onset of proteinuria, effectively inhibited IgG autoantibody production, and significantly reduced hypercellularity and deposition of IgG in glomeruli, resulting in almost complete amelioration of lupus nephritis in these animals. Our results indicate the therapeutic potential of simultaneous stimulation of PD-1-mediated pathway and blockade of ICOS-B7h co-stimulation in the prevention of human lupus nephritis.     

Experimental lupus nephritis in severe combined immunodeficient (SCID) mice: remodelling of the glomerular lesions by bystander IgM antibodies

MRL/Mp-lpr/lpr (MRL/lpr) mice develop glomerular lesions with regular variations in their histopathological manifestations, similar to those in lupus nephritis. These lesions are mainly either cell-proliferative or wire loop-like and are associated with glomerular deposits of immunoglobulins, most frequently IgG and IgM. We previously established a nephritogenic IgG3-producing hybridoma clone, B1, from an MRL/lpr mouse, which induces only a 'wire loop-like' type of glomerular lesion when injected into SCID mice. Injection of SCID mice with an anti-trinitrophenyl IgM antibody-producing hybridoma clone, Sp6, following injection of the B1 clone, however, resulted in the development of a 'cell-proliferative' type of glomerular lesion, associated with an accumulation of both antibodies in glomeruli. This accumulation occurred even though Sp6 IgM antibodies did not react with B1 IgG3 antibodies and vice versa. A mutant clone of Sp6, T/13microE/3.1, which produces antibodies deficient in C1q binding, produced a similar effect as that of the Sp6 clone, i.e. 'cell-proliferative' lesions. Again the B1 antibodies did not react with T/13microE/3. 1-IgM antibodies and vice versa. We therefore conclude that bystander IgM antibodies contribute to the remodelling of glomerular lesions in situ, following glomerular injury by the nephritogenic antibodies.     

Induction of microthrombotic thrombocytopenia in normal mice by transferring a platelet-reactive, monoclonal anti-gp70 autoantibody established from MRL/lpr mice: an autoimmune model of thrombotic thrombocytopenic purpura

MRL/MpJ-lpr/lpr (MRL/lpr) mice spontaneously develop immune complex-mediated glomerulonephritis and thrombocytopenia. Although the presence of cross-reactive anti-phospholipid antibodies in sera of MRL/lpr mice has been demonstrated, possible relationships between detected autoantibodies and the development of thrombocytopenia have not been elucidated. Recent genetic analyses in a few different strains of lupus-prone mice have pointed out a close correlation between autoantibodies reactive with endogenous retroviral env gene product, gp70, and the development and severity of glomerulonephritis. In the process of establishing possibly nephritogenic anti-gp70 autoantibody-producing hybridoma cells from MRL/lpr mice, we identified an IgG2a-producing anti-gp70 hybridoma clone that induced microvascular intraluminal platelet aggregation, thrombocytopenia, and amenia upon transplantation into syngeneic non-autoimmune mice. This and two other anti-gp70 antibodies bound onto the surface of mouse platelets, and purified IgG2a of the anti-gp70 autoantibody induced glomerular lesions with characteristics of thrombotic thrombocytopenic purpura when injected into non-autoimmune mice. The pathogenic anti-gp70 autoantibody specifically precipitated a platelet protein with an approximate relative molecular mass of 40 000.     

Modulation of the immune response in pristane-induced lupus by expression of activation and inhibitory Fc receptors

Altered homeostasis in Fcgamma receptor (FcgammaR) expression has been implicated in the induction of both immune complex-mediated glomerulonephritis and autoantibody production in systemic lupus erythematosus. FcgammaRI and III are required for immune complexes to activate inflammatory cells, thereby inciting tissue injury. In contrast, FcgammaRIIB functions as a negative regulator of immune complex-mediated inflammation and autoantibody production. We investigated the role of FcgammaRI/III versus FcgammaRIIB on pristane-induced lupus in mice. FcgammaRI/III and FcgammaRIIB-deficient ((-/-)) and control ((+/+)) BALB/c mice were injected with either pristane or PBS. Proteinuria and glomerular immune deposits were evaluated 9 months after treatment and serial sera were analysed for total IgG levels and lupus-specific autoantibodies. The incidence of nephritis was higher in pristane-treated FcgammaRIIB(-/-) mice than pristane-treated FcgammaRI/III(-/-) and (+/+) mice. Hypergammaglobulinaemia and spontaneous anti-DNA/chromatin autoantibody production were associated with interleukin (IL)-6 over-expression in FcgammaRIIB(-/-) mice and were augmented further by pristane treatment when compared to both FcgammaRI/III(-/-) and (+/+) mice. Lack of either FcgammaRIIB or FcgammaRI/III had little effect on both anti-nRNP/Sm and anti-Su production induced by pristane. Our results confirm that spontaneous autoimmunity occurs in the absence of FcgammaRIIB. Moreover, the lupus-like syndrome induced by pristane in BALB/c mice was regulated by opposing activating and inhibitory FcgammaRs. Activating FcgammaRs were required for significant proteinuria and unbridled activation in the absence of FcgammaRIIB dramatically exacerbated glomerular inflammatory responses. FcgammaRIIB may be a key modulator that suppresses cell activation in the inflammatory immune response in systemic lupus erythematosus in humans.     

Parasites alter the pathological phenotype of lupus nephritis

Abstract

Lupus nephritis is one of the most serious complications of systemic lupus erythematosus and manifests with considerable phenotypic and histological heterogeneity. In particular, diffuse proliferative lupus nephritis (DPLN) and membranous lupus nephritis (MLN) represent morphologic forms that are polar opposites. DPLN is associated with autoimmune responses dominated by Th1 immune response associated with high levels of interferon (IFN)-γ. In contrast, a Th2 cytokine response is associated with the pathogenesis of MLN. MRL/lpr mice develop human LN-like immune complex-associated nephritis and provide a suitable histological model for human DPLN. Infection with Schistosoma mansoni skewed a Th2-type immune response induction and IL-10 in MRL/lpr mice, drastically changing the pathophysiology of glomerulonephritis from DPLN to MLN accompanied by increased IgG1 and IgE in the sera. T cells in 32-week-old MRL/lpr mice infected with S. mansoni expressed significantly more IL-4 and IL-10 than T cells of uninfected mice; T cells with IFN-γ were comparable between infected and uninfected MR/lpr mice. Thus, the helminthic infection modified the cytokine microenvironment and altered the pathological phenotype of autoimmune nephritis.     

Non-MHC genes determine the development of lupus nephritis in H-2 identical mouse strains

Susceptibility to systemic lupus erythematosus (SLE) and, in particular, lupus nephritis is strongly influenced by genetic factors. Previous studies have shown that MHC-related antigens influence the development of SLE. In the current study, we set out to investigate how non-MHC genes influence the pathogenesis of glomerulonephritis in chronic graft-versus-host disease (GVHD) in mice, a model for lupus nephritis. For the induction of GVHD we used parent-to-F₁ hybrid mouse strain combinations. DBA/2, BALB/c, BALB.D2 and C57Bl/10.D2 (BL10.D2) donor lymphocytes carrying an H-2^d haplotype were injected into H-2^b/d F₁ hybrids of BL10 mice, which differed only at non-MHC loci. Within these hybrid strains the development of immune complex glomerulonephritis was investigated by monitoring the occurrence of autoantibodies in the circulation, deposition of immunoglobulins in the glomeruli, development of albuminuria, and glomerulosclerosis. In diseased DBA/2 mice albuminuria developed 6 weeks after induction of the disease. Mice with a BALB background developed a lupus-like syndrome characterized by albuminuria starting 8 weeks after induction of the GVHD. During the development of the GVHD, polyclonal B cell activation occurred in both the DBA/2 and BALB/c strains, resulting in the formation of autoantibodies. Only the strain combination using DBA/2 mice developed anti-GBM antibodies. In DBA/2 and BALB strain combinations immune complexes were detected in a granular pattern along the glomerular capillary walls. In the DBA/2 recipients a linear pattern of immunoglobulin depositions preceded the granular phase. This study demonstrates that: (i) non-MHC genes govern the pathogenesis of immune complex nephritis in this model by influencing the autoantibody profile; and (ii) the presence of anti-GBM antibodies in the early stages of the disease is a conditio sine qua non for the development of full-blown glomerulonephritis and glomerulosclerosis in this model.     

Macrophage depletion ameliorates nephritis induced by pathogenic antibodies

Kidney involvement affects 40–60% of patients with lupus, and is responsible for significant morbidity and mortality. Using depletion approaches, several studies have suggested that macrophages may play a key role in the pathogenesis of lupus nephritis. However, “off target” effects of macrophage depletion, such as altered hematopoiesis or enhanced autoantibody production, impeded the determination of a conclusive relationship. In this study, we investigated the role of macrophages in mice receiving rabbit anti-glomerular antibodies, or nephrotoxic serum (NTS), an experimental model which closely mimics the immune complex mediated disease seen in murine and human lupus nephritis. GW2580, a selective inhibitor of the colony stimulating factor-1 (CSF-1) receptor kinase, was used for macrophage depletion. We found that GW2580-treated, NTS challenged mice did not develop the increased levels of proteinuria, serum creatinine, and BUN seen in control-treated, NTS challenged mice. NTS challenged mice exhibited significantly increased kidney expression of inflammatory cytokines including RANTES, IP-10, VCAM-1 and iNOS, whereas GW2580-treated mice were protected from the robust expression of these inflammatory cytokines that are associated with lupus nephritis. Quantification of macrophage related gene expression, flow cytometry analysis of kidney single cell suspensions, and immunofluorescence staining confirmed the depletion of macrophages in GW2580-treated mice, specifically within renal glomeruli. Our results strongly implicate a specific and necessary role for macrophages in the development of immune glomerulonephritis mediated by pathogenic antibodies, and support the development of macrophage targeting approaches for the treatment of lupus nephritis.     

Bone marrow cell transfer of autoimmune diseases in a MRL strain of mice with a deficit in functional Fas ligand: dissociation of arteritis from glomerulonephritis

MRL/MpTn-gld/gld (MRL/gld) mice, which are deficient in a functional Fas ligand (FasL), spontaneously develop autoimmune diseases involving both lethal glomerulonephritis and systemic arteritis, while MRL/Mp-+/+ (MRL/+) and C3H/HeJ-gld/gld (C3H/gld) do not. To determine the cells responsible for the development of glomerulonephritis and arteritis, we transferred bone marrow cells from MRL/gld mice to undiseased MHC-compatible gld/gld or +/+ mice. In bone marrow irradiation chimeras, MRL/gld bone marrow cells were transferred to lethally irradiated MRL/+ or C3H/HeJ-+/+ (C3H/+) mice, and both recipients developed glomerulonephritis associated with hypergammaglobulinemia without causing graft-versus-host (GVH)-like diseases. However, a striking difference between them was that MRL/+ recipients developed arteritis, but C3H/+ recipients did not. In bone marrow mixed chimeras formed by transferring MRL/gld bone marrow cells to unirradiated mice, the MRL/gld bone marrow cells induced glomerulonephritis in C3H/gld mice, but not in C3H/+ and MRL/+ mice. These results indicate that bone marrow cells from MRL/gld mice can cause glomerulonephritis in mice, even in those with a C3H background, possibly if they survive longer by escaping from Fas-mediated apoptosis, while the development of arteritis requires the MRL genetic background in the recipients. This is the first report of the transfer of arteritis in lupus mice to undiseased recipients.     

Prevention of lupus nephritis development in NZB/NZW mice by selective blockade of CD28

Systemic lupus erythematosus (SLE) is a chronic systemic inflammatory disease. Autoantibodies (autoAbs) against double‐stranded DNA (ds DNA), the hallmark of lupus, are produced and maintained by the interaction between auto‐reactive B cells and CD4⁺ T cells. This interplay is controlled by the CD28/CD80‐86/CTLA‐4 axis. Here we investigated whether selective blockade of CD28‐CD80/86 co‐stimulatory interactions abrogates lupus nephritis development in a murine model of SLE. To this aim, NZB/NZW F1 mice were treated for 3 months, either with an anti‐CD28 Fab’ fragment or a control Fab’‐IgG. The effect of CD28 blockade on lupus nephritis onset, survival, production of anti‐ds DNA antibodies and costimulatory molecules was evaluated. CD28 blockade prevented the development of lupus nephritis and prolonged survival during the 3‐month treatment and 12 weeks after. Furthermore, the production of anti‐ds DNA autoAbs was decreased. Lastly, the protective effect of CD28 blockade was associated with increased intrarenal expression of the immunoregulatory molecule, Indoleamine 2, 3‐dioxygenase, of the co‐inhibitory receptor programmed cell‐Death – 1 (PD‐1) and of its ligand programmed death ligand ‐ 1 (PDL‐1).In conclusion, CD28 blockade prevented the development of lupus nephritis in NZB/NZW F1 mice. This immunomodulatory strategy is a promising candidate for SLE therapy in humans.     

Overexpression of Epstein–Barr virus-induced gene 3 protein (EBI3) in MRL/lpr mice suppresses their lupus nephritis by activating regulatory T cells

Abstract

To identify the effect of an imbalance of Th1/Th2 cytokines on the development of autoimmune glomerulonephritis (lupus nephritis), we studied the modification of pathological changes in diffuse proliferative glomerulonephritis (DPGN) and membranous glomerulonephritis (MGN) in MRL/lpr mice, which are animal models of systemic lupus erythematosus (SLE). Transgenic MRL/lpr mice (Tg) that overexpressed Epstein--Barr virus-induced gene 3 (EBI3) showed almost normal renal function, which was demonstrated by healing of glomerulonephritis upon renal histology, as compared to the wild-type MRL/lpr (Wt) mice. The levels of anti-dsDNA antibodies and IgE decreased in the Tg mice compared to Wt mice. Quantitative real-time PCR indicated an increase in the mRNA levels of FoxP3, and a decrease in that of IFNγ in the splenocytes of Tg mice as compared to Wt mice. In addition, flow cytometric analysis showed an increase in CD4⁺CD25⁺FoxP3⁺-T cells in the former, as compared to the latter. Our findings suggest that EBI3-overexpression in MRL/lpr mice induces generation of regulatory T cells, which causes suppression of autoimmune and inflammatory reactions by affecting the Th1/Th2 cytokine balance.     

L-4F改善狼疮样小鼠肾脏病变

 目的:探讨载脂蛋白A-I类似肽（L-4F）对apoE-/-Fas-/-C57BL/6 狼疮样小鼠自发性狼疮肾病变的影响。方法:选用8～9周龄的雌性小鼠,腹腔注射L-4F,治疗25周。观察肾脏病理改变,测定自身抗体相关细胞因子、脂联素及尿蛋白水平。结果:与apoE-/-Fas-/-C57BL/6小鼠相比,L-4F治疗使apoE-/-Fas-/- C57BL/6小鼠的淋巴结和肾小球的大小均显著减小(P<0.05),并降低血清抗双链DNA 抗体、抗氧化磷脂类抗体、IL-6和TNF-α的循环水平,同时提高小鼠血清脂联素水平 (P<0.05)。结论: L-4F能显著改善狼疮样小鼠的肾脏病变,对治疗狼疮肾具有一定的临床应用价值。     

Interferon regulatory factor-1 gene deletion decreases glomerulonephritis in MRL/lpr mice

To investigate the role of interferon regulatory factor-1 (IRF-1) in the development of lupus nephritis, IRF-1(-/-) genotype mice were bred onto the MRL/lpJfas(lpr) (MRL/lpr) background. We examined kidney mesangial cell function and disease progression. Endpoints evaluated included inflammatory mediators, autoantibody production, immune complex deposition, renal pathology, T cell subset analysis, and duration of survival. Mesangial cells cultured from IRF-1(-/-) mice produced significantly lower levels of nitric oxide and IL-12 but not TNF-alpha when stimulated with LPS + IFN-gamma. IRF-1(-/-) mice showed less aggravated dermatitis compared to the wild-type mice. Anti-double-stranded DNA production and proteinuria were significantly decreased in IRF-1(-/-) mice compared to IRF-1(+/+) mice. IgG and C3 deposition as well as glomerulonephritis were decreased in IRF-1(-/-) mice at 26 wk of age compared to the IRF-1(+/+) mice. Splenic CD4- CD8- CD44+ T cells were decreased while CD4+ CD25+ T cells were increased in the IRF-1(-/-) mice when compared to IRF-1(+/+) mice. Survival rates (ED50) were 22 wk for IRF-1(+/+) mice and 45 wk for IRF-1(-/-) mice. These findings suggest an important role of IRF-1 in mediating renal disease in MRL/lpr mice.     

RANTES Deficiency Attenuates Autoantibody-Induced Glomerulonephritis

Experimental autoimmune nephritis in mice and spontaneous lupus nephritis are both associated with elevated expression of several chemokines in the kidneys. Nevertheless, the role that different chemokines play in mediating renal inflammation is far from complete. This study focuses on elucidating the functional role of RANTES, a chemokine that has been noted to be hyper-expressed within the kidneys, both in experimental renal disease as well as in spontaneous lupus nephritis. To elucidate if RANTES was essential for immune-mediated glomerulonephritis, DBA/1 mice that are highly sensitive to nephrotoxic serum nephritis were rendered RANTES-deficient and then tested for disease susceptibility. Nephritis-sensitive DBA/1 mice expressed more RANTES within the diseased kidneys. Compared to wild-type DBA/1 mice, RANTES-deficient DBA/1 mice developed significantly less proteinuria, azotemia, and renal inflammation, with reduced crescent formation and tubulo-interstitial nephritis. These findings indicate that RANTES ablation attenuates immune-mediated nephritis and suggest that this chemokine could be a potential therapeutic target in these diseases.     

Gender-related influences on the development of chronic graft-versus-host disease-induced experimental lupus nephritis.

Autoimmune diseases are far more common in women than in men. In the incidence of systemic lupus erythematosus (SLE), the female-to-male ratio is as high as 10:1. This suggests that sex hormones may play a fundamental role in determining the susceptibility to these diseases. In order to investigate the sex-related differences in the inducibility of chronic graft-versus-host disease-related experimental lupus nephritis, lymphocytes from female DBA/2 donor mice were administered to either male or female (C57BL10 x DBA/2)F1 recipients. An additional group of male recipients received lymphocytes from male DBA/2 donors. After four cell transfers, female recipients developed a significantly higher albuminuria than both male groups. Serum concentrations of autoantibodies against glomerular basement membrane (GBM), collagen IV, and laminin were significantly higher in females 2-4 weeks after induction. Levels of circulating autoantibodies against renal tubular epithelial antigens (RTE) and nuclear antigens were not different between the sexes. In transfer studies, the necessity of the presence of anti-GBM and anti-RTE autoantibodies for the development of glomerulonephritis was confirmed. These findings indicate that: (i) in this model of lupus nephritis, susceptibility to glomerulonephritis is strongly influenced by sex-related genes; and (ii) among the variety of autoantibodies occurring in this model of SLE, both anti-GBM and anti-RTE autoantibodies play a key role in the pathogenesis of glomerulonephritis.     

Ageing,Auto Antigen Specific-Ts Cells,Involution of the Thymus,Autoimmunity and Autoimmune Diseases

We have studied the ability of the lupus prone MRL Ipr/lpr (MRL/lpr) and (NZB×NZW)F₁ (NZB/W) female mice to raise granulocyte mediated inflammatory responses. These autoimmune strains, known to exhibit severe anergy as concerns T cell dependent immune function, are not well analysed with respect to neutrophil-mediated inflammatory responses. An in vivo model of granulocyte mediated inflammation has been developed in our laboratory. A single intradermal injection of olive oil into mouse footpad induces massive infiltration of polymorphonuclear cells (PMNC) within 24 h. This extravasation of PMNC gives rise to a localized footpad swelling, which can be easily and reproducibly measured and relates to severity of the inflammatory process. T cell independence of this inflammatory model was ascertained by in vivo T cell depletion using monoclonal antibodies to CD4 and CD8 molecules.

Olive oil triggered inflammation was inducible in both young and aged lupus mice. The intensity of footpad swelling upon olive oil injection was similar in lupus mice and in healthy control strains. In contrast, aged MRLflpr and NZBW mice showed severely depressed T cell dependent inflammatory responses as assessed by delayed type hypersensitivity reaction to sheep red blood cells.

We conclude that the PMNC mediated inflammatory potential is not affected in severely diseased lupus mice. The increased numbers of circulating PMNC together with intact PMNC function may explain why severely immune deficient lupus mice seldom show clinical signs of bacterial infection.     

Glomerular expression and elevated serum Bcl-2 and Fas proteins in lupus nephritis: preliminary findings

Programmed cell death (apoptosis) is involved in glomerular injuries leading to glomerulonephritis. Bcl-2 and Fas are proteins that promote cell survival and death, respectively. This study tests the hypothesis that lupus nephritis is associated with alterations of Bcl-2 and Fas protein expression. Thirty-six patients with lupus nephritis and 10 controls (normal individuals) were included in this study. Bcl-2 and Fas positive cells were examined in kidney biopsies by immunohistochemistry. Bcl-2 and Fas serum levels were evaluated by enzyme-linked immunosorbent assay (ELISA). In the glomeruli of normal kidneys, Bcl-2 and Fas proteins were completely absent. In lupus nephritis patients, glomerular expression of Bcl-2 and Fas was seen in mesangial cells (1.3 +/- 0.1 and 2.0 +/- 0.1 for Bcl-2 and Fas, respectively). Similarly, a statistically significantly higher Bcl-2 (217.1 +/- 85.9) and Fas (767.9 +/- 271) serum levels were found in lupus patients compared to controls (148.6 +/- 87, 550.3 +/- 91 for Bcl-2 and Fas, P < 0.05). A direct correlation between serum Bcl-2 and Fas and chronicity index was also found. Compared to normal controls, lupus nephritis is associated with glomerular expression and elevated serum levels of Bcl-2 and Fas proteins. These findings suggest possible roles for Bcl-2 and Fas in glomerular injury during evolution of lupus nephritis. The diagnostic, prognostic and therapeutic ramifications of our findings are open to further investigation.