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J Schiffenbauer

Publications and source records attributed to J Schiffenbauer.

At least 19 recordsLinked to original sources
PubMed2004

Randomized controlled trials in systemic lupus erythematosus: what has been done and what do we need to do?

The study of systemic lupus erythematosus (SLE) is a challenging undertaking. It is difficult to assess outcomes in SLE randomized controlled trials (RCTs), and this is illustrated by the lack of new therapies approved for use in lupus. In a disease that is waxing and waning, and requires constantly changing medications, identifying treatment effects of new therapies may be difficult, and the use of potentially toxic therapies requires a rigorous understanding of the benefit to risk ratio. Some issues that need to be considered by the investigator in designing these studies include: 1) should the trial focus on patients with active or inactive disease; 2) which of the measures of disease activity should be used or should prevention of flares be examined; 3) should the study focus on defined organ specific endpoints or utilize one of the available disease activity indices to identify changes in disease activity; 4) should the trial be a superiority trial or an equivalence trial. This review summarizes the critical issues involving the design of studies in lupus and provides the reader with suggestions and recommendations for consideration before embarking on trials in this area.

Humans↗
PubMed2000

Interleukin-2 gene deletion produces a robust reduction in susceptibility to experimental autoimmune encephalomyelitis in C57BL/6 mice.

Dysregulation of interleukin-2 (IL-2), the prototypical T cell growth factor and immunoregulatory cytokine, may modify self-tolerance and predisposition to autoimmunity. The available literature suggested that IL-2 could be hypothesized to either propagate or inhibit the development autoimmune demyelinating disorders of the central nervous system such as multiple sclerosis. Thus, the present study sought to test these competing hypotheses by examining whether disrupting one or both IL-2 gene alleles would render mice more or less vulnerable to experimental autoimmune encephalomyelitis (EAE). Myelin oligodendrocyte glycoprotein was used to induce EAE in C57BL/6-IL-2(-/-) knockout, C57BL/6-IL-2(+/-) heterozygote and C57BL/6-IL-2(+/+) wild-type mice. All of the wild-type and heterozygote mice developed signs of EAE compared with only 23% of the IL-2 knockout mice. Histopathological examination of lumbar spinal cord sections confirmed that subpial perivascular inflammatory infiltrates found in wild-type and heterozygote mice were absent in the unaffected IL-2 knockout mice. These data demonstrate that vulnerability to EAE is markedly reduced in C57BL/6 mice lacking IL-2, and suggest that this cytokine may play a critical role in autoimmune processes of the central nervous system.

Animals↗
PubMed2000

The induction of EAE is only partially dependent on TNF receptor signaling but requires the IL-1 type I receptor.

Experimental autoimmune encephalomyelitis develops in mice immunized with CNS antigens. To elucidate the role that specific proinflammatory cytokines play in the induction of this process we examined the development of EAE in mice with targeted disruptions of the TNF p55 or p75 or the IL-1 p80 receptors. EAE developed in mice with either one or both TNF receptors deleted although the onset of disease in mice with the p55 receptor deleted was delayed. However, mice with a deletion of the IL-1 p80 receptor failed to develop any inflammatory lesions in the CNS or evidence of clinical EAE. Thus we conclude that TNF or its receptors contribute to, but are not necessary for, the induction of EAE while the IL-1 p80 receptor is absolutely required. The p55 TNF receptor plays a role in determining the onset of disease and its severity.

Animals↗
PubMed1999

Genetic dissection of SLE pathogenesis: adoptive transfer of Sle1 mediates the loss of tolerance by bone marrow-derived B cells.

Sle1 is a potent autoimmune susceptibility locus on chromosome 1 originally identified in a genome scan of testcross progeny between the systemic lupus erythematosus-prone NZM2410 strain and C57BL/6. We subsequently produced B6.NZMc1, a congenic strain carrying the NZM2410-derived Sle1 genomic interval on the B6 background and demonstrated that Sle1 mediated the loss of tolerance to chromatin in both the B and T cell compartments. In this communication, we show by adoptive transfer experiments that the autoimmune phenotypes of Sle1 are completely reconstituted in B6 radiation chimeras receiving B6.NZMc1 bone marrow but not by the reciprocal reconstitution, demonstrating that Sle1 is functionally expressed in B cells. In additional experiments, cotransfer of mixtures of bone marrow derived from B6.NZMc1 and nonautoimmune congenic B6 mice carrying allelic T and B cell markers showed that only B cells derived from B6.NZMc1 bone marrow produced anti-chromatin autoantibodies. In contrast, increased expression of CD69 was equivalent in CD4+ T cells derived from either B6.NZMc1 or congenic B6 bone marrow, suggesting that either T cell population could be activated subsequent to loss of tolerance in the B cell compartment. These findings indicate that the expression of Sle1 in B cells is essential for the development of autoimmunity.

Adoptive Transfer↗
PubMed1999

Multiplex inheritance of component phenotypes in a murine model of lupus.

We analyzed the linkage of GN and a wide spectrum of serological phenotypes associated with systemic lupus erythematosus in a (NZM2410 x C57BL/6)F2 cross. Some phenotypes, such as glomerulonephritis (GN) and anti-chromatin IgG antibody production, were more penetrant in females, but others, such as anti-dsDNA antibody production, did not show a gender bias. These results suggest that gender bias affects only a subset of SLE-component phenotypes, and that NZM2410 can be used to dissect the genetic basis of this phenomenon. Genome scanning linked six chromosomal intervals with the expression of one or more component phenotypes. These loci included two Sle loci previously identified in an (NZM2410 x B6)F1 x NZM2410 backcross, loci identified by others in the NZB/W model. Our analysis also suggested two new intervals on chromosomes (Chrs.) 10 and 11. Detailed analysis of the segregation of different phenotypes within these intervals suggests that they encompass more than one susceptibility locus. This clustering has been a common finding in several murine polygenic traits. Each of NZM2410 susceptibility loci can be aligned with a specific genetic pathways contributing to SLE pathogenesis on the basis of the spectrum of component phenotypes expressed.

Animals↗
PubMed1999

Aberrant expression of the NF-kappaB and IkappaB proteins in B cells from viable motheaten mice.

In viable motheaten mice, a mutation in the gene encoding the phosphatase, SHP1, causes severe immunodeficiency and autoimmunity. A defective phosphatase may result in modified phosphorylation of proteins involved in gene regulation. Since the NFkappaB/IkappaB proteins are regulated through phosphorylation, we wished to understand if the expression of these proteins was altered by the SHP1 defect. Splenic B cells from viable motheaten mice were isolated and assessed for purity by flow cytometry. Levels of each protein in isolated B cells were examined by Western blot analyses. Measurement of RNA levels for each protein was assessed by semi-quantitative RT-PCR. Western blots revealed that, in me(v) whole cell lysates, there were reduced levels of RelA and RelB proteins and increased levels of p50 and c-Rel. Furthermore, we analyzed the protein levels of IkappaBalpha and found that, in me(v), this inhibitor was significantly reduced, while the level of another member of the IkappaB family, IkappaBbeta, was not. To determine if these findings in me(v) were secondary to the autoimmune process, we evaluated NF-kappaB/IkappaB expression in the BXSB murine model of autoimmunity. Unlike me(v), B cells from BXSB/Yaa mice had NF-kappaB complexes composed of the RelA submit, and IkappaBalpha was readily detected. In addition, RNA for the RelA and IkappaBalpha proteins in me(v) and control littermates was detected by RT-PCR, indicating that the reduced amounts of these proteins was not exclusively due to transcriptional defects. We conclude that the differences in NF-kappaB/IkappaB proteins that we have described in me(v) are likely a consequences of the SHP1 defect and could contribute to the clinical disorder that characterizes me(v) mice.

Animals↗
PubMed1999

Superantigens and their role in autoimmune disorders.

The ability of superantigens to activate large numbers of T cells suggests that they may play a role in the course of autoimmune disorders. Data from several animal models of autoimmune disorders including experimental allergic encephalomyelitis and collagen induced arthritis supports this hypothesis. Administration of bacterial superantigens can induce an exacerbation of the autoimmune process in these models, or induce disease de novo in the appropriately immunized animal. Studies of several human disorders including rheumatoid arthritis, Kawasaki disease, insulin-dependent diabetes, and psoriasis lend credence to the concept that bacterial superantigens may play a role in the pathogenesis of these diseases. Nevertheless, in some cases, depending on the timing of administration and the model, superantigens may lead to an amelioration of the autoimmune process. Based on these results in seems logical to conclude that superantigens can have a significant impact on the course of the immune and autoimmune mediated disorders.

Animals↗
PubMed1998

Prevention of experimental allergic encephalomyelitis by an antibody to CD45RB.

CD45 is involved in the regulation of lymphocyte activation, and it has been demonstrated that ligation of CD45 induces apoptosis of T and B lymphocytes. Recently anti-CD45RB antibody therapy was shown to block acute allograft rejection in a mouse model of transplantation. Therefore, we wanted to examine the effects of anti-CD45RB antibody treatment on the course of an autoimmune disorder, experimental allergic encephalomyelitis (EAE), a Th1-mediated process. Mice immunized with myelin basic protein and treated with anti-CD45RB antibody did not develop EAE. Histologically, there was no evidence of lymphocytic infiltrates in the central nervous system. T cell proliferation and TNF-alpha production were significantly decreased in anti-CD45RB-treated mice. Furthermore, there was a significant reduction in the production of other Th1 cytokines including interferon-gamma and IL-2, but not IL-4 or IL-6. However, levels of a number of adhesion markers or markers of activation such as VLA-4 and LFA-1 on T cells were no different in treated versus control animals. Thus, anti-CD45RB can prevent EAE and appears to do so by altering T cell proliferation and cytokine production.

Animals↗
PubMed1998

Resistance to HgCl2-induced autoimmunity in haplotype-heterozygous mice is an intrinsic property of B cells.

Exposure to low doses of mercury chloride induces autoantibodies to the nucleolar protein fibrillarin in H-2s, but not in H-2b, mice. Surprisingly, F1 crosses between resistant and sensitive haplotypes are resistant. Previously, we have shown that the resistance in these F1 mice was due to coexpression of the resistant class II allele. Using adoptive transfer techniques we have examined several mechanisms by which the resistant haplotype could be down-regulating the antifibrillarin response in F1 (s/b) mice. Similar to other autoimmune models, mercury-induced autoimmunity requires cognate MHC-restricted T cell help. The absence of autoantibody production in F1 mice was not due to a difference in thymic education or to the absence of antifibrillarin-specific T cell help. These results suggest that the resistance is due to an intrinsic property of the haplotype-heterozygous B cells.

Animals↗
PubMed1998

Functional consequences of the SHP-1 defect in motheaten viable mice: role of NF-kappa B.

To define the functional consequences of the src-homology domain-1 protein (SHP-1) defect, we examined cytokine production and NF-kappa B activity in motheaten viable (Mev) mice. We found elevated levels of interleukin-6 (IL-6), interleukin-10 (IL-10), tumor necrosis factor (TNF), and interferon-gamma (IFN-gamma) in Mev mice sera and cultured B and T cells compared to littermate control adult mice. The levels of interleukin-2 (IL-2) detected in Mev sera and activated Mev T cells were decreased, but IL-2 receptor expression was increased. We then evaluated the activity of NF-kappa B and found that this protein is highly expressed in Mev B and T cells. To determine if NF-kappa B had a role in causing the elevated levels of cytokines in Mev mice, we treated activated Mev T cells with an NF-kappa B decoy and found that cell culture treatment with the decoy resulted in significant reduction of the secretion of IL-6, GM-CSF, and TNF, but not IFN-gamma. Therefore, our data show that Mev mice secrete elevated levels of inflammatory cytokines, which can be mediators in the development of the Mev clinical disorder, and that NF-kappa B has an important role in this process, impacting upon the regulation of the immune response.

Animals↗
PubMed1998

Novel immunoregulatory B cell pathways revealed by lpr-+ mixed chimeras.

lpr, a murine mutation of the Fas apoptosis receptor, causes lymphadenopathy and autoantibody production, with lymphadenopathy primarily due to a population of CD4-CD8-B220+ T cells. Previous in vivo experiments, in which lpr and normal bone marrow cells were coinfused into lpr hosts, have demonstrated that only T cells of lpr origin accumulated abnormally and only B cells of lpr origin produced autoantibodies. Moreover, in these chimeras, B cells of normal origin were unable to respond to conventional, T cell-dependent exogenous Ag. To address the role of lpr B cells in regulation of lpr autoimmunity, we have prepared lpr-+ mixed chimeras and selectively eliminated lpr B cells using allele-specific, mAb treatment, thus allowing normal B cells to develop in an environment with lpr T cells. From these data, we arrived at four major conclusions: 1) Compared with control-treated chimeric mice, lpr B cell-depleted mice had greatly reduced total lymph node cell counts; 2) the T cells were derived equally from normal and lpr donors, and the percentage of lpr-derived CD4-CD8- T cells was greatly reduced; 3) despite the presence of the remaining lpr T cells, no autoantibodies were produced by the normal derived B cells; and 4) lpr T cells without lpr B cells were unable to prevent a normal B cell response to conventional Ag. These data demonstrate that B cells can play a critical and expansive regulatory role, not only for T cells, but for other B cells as well.

Animals↗
PubMed1998

Use of phosphorothioate-modified oligodeoxynucleotides to inhibit NF-kappaB expression and lymphocyte function.

NF-kappaB is a potential target for immunosuppressive therapy. Two methods were evaluated to inhibit NF-kappaB: the antisense (AS) approach in which single-stranded oligodeoxynucleotides (ODNs) bind the mRNA for the RelA subunit of NF-kappaB and the transcription factor decoy (TFD) approach in which double-stranded ODNs bind the NF-kappaB protein. AS and TFD inhibited NF-kappaB binding and decreased total IgG and anti-dsDNA antibody production in splenocytes from the BXSB/Yaa autoimmune mouse strain. TNF-alpha expression was reduced by AS and TFD, as were the levels of IL-2. But AS effects did not last beyond 24 h, whereas TFD inhibited cytokine production after 72 h. AS had no effect upon IL-6, while the TFD reduced the secretion of IL-6. Therefore, the suppression of immune response mediators by AS or TFD, through inhibition of NF-kappaB, is substantial. These inhibitors can serve as novel choices for therapy in the treatment of autoimmune disorders.

Animals↗
PubMed1997

Inhibition of the p50 (NKkappaB1) subunit of NF-kappaB by phosphorothioate-modified antisense oligodeoxynucleotides reduces NF-kappaB expression and immunoglobulin synthesis in murine B cells.

NF-kappaB is a regulatory protein of immune response genes and a candidate for targeting in immunosuppressive therapy. NF-kappaB proteins are formed from components of which p50 (NFkappaB1) is a subunit. By targeting p50 gene expression with specific antisense 3' phosphorothioate-oligodeoxynucleotides (3' PS-ODNs), an effect upon NF-kappaB regulation and immunoglobulin synthesis in murine B cells was achieved. A 49% decrease in p50 protein was induced by treatment of WEHI 231 B cells with p50 antisense 3' PS-ODNs and not by control 3' PS-ODNs. p50 antisense specifically reduced the expression of NF-kappaB by 51%, but not the transcription factor, Oct-1. In the BXSB murine model of autoimmunity, p50 antisense inhibited NF-kappaB expression and total IgM and IgG synthesis, but, more importantly, dsDNA antibodies were reduced 90%. These results validate the use of p50 antisense to reduce NF-kappaB expression and, by downregulating the immune response, has application in the treatment of autoimmune disorders.

Animals↗
PubMed1997

Class II haplotype differentially regulates immune response in HgCl2-treated mice.

One of the most striking features of exposure to low doses of mercury in mice is the high-titer haplotype-linked anti-nucleolar (ANoA) autoantibody response. Mice of H-2(s) haplotype have been high responders, while H-2(b) mice have been low. This pattern has been attributed to the class II molecule itself, but the poor response of F1 crosses between high and low responders raised the possibility that the anti-fibrillarin specificity was actually due to a closely linked dominant negative gene. To test the role of class II explicitly, F1 crosses between congenic B6.SJL (H-2(s)) and C57BL/6 (H-2(b)) mice with a targeted deletion of I-AbAbeta were generated, creating mice heterozygous for all MHC loci, but expressing only I-As. In comparison with B6.SJL, no diminution of ANoA titers was found, proving that I-As itself was responsible for susceptibility and I-Ab for downregulation. Unlike I-A, expression of the I-E class II molecule could not downregulate the response in an otherwise susceptible mouse. These results suggest a complicated role for class II in the regulation of a novel, environmentally induced autoimmune response.

Animals↗
PubMed1997

Superantigens as virulence factors in autoimmunity and immunodeficiency diseases.

Virulence factors are microbial products that are known to be harmful to the host and may assist in the pathogenesis of the micro-organism. Superantigens, including those produced by bacteria and viruses, clearly act as virulence factors. The clinical effects of superantigens can be not only acute but also chronic and complex. Recent evidence suggests that superantigens may play a central role in the pathogenesis of autoimmune and immunodeficiency disorders. It is our contention that superantigens, as environmental factors, can change a controllable disease into one that becomes relentless for susceptible individuals. To illustrate the detrimental effects of superantigens on disease outcome, modulation of experimental allergic encephalomyelitis by superantigen, as well as the potential role of superantigens in human immunodeficiency virus pathogenesis will be discussed. The information presented may provide valuable insight into the role of superantigens in autoimmunity and human immunodeficiency virus infection.

Animals↗
PubMed1996

Hyperproliferation of BXSB B cells is linked to the Yaa allele.

Systemic lupus erythematosus is characterized by polyclonal B cell activation, the production of autoantibodies, and often by renal disease. Previous studies demonstrated that unfractionated B cells from several strains of mice with lupus hyperproliferate in culture when stimulated with lipopolysaccharide (LPS) or anti-IgM. We wished to further examine proliferation of resting B cells from the BXSB mouse model of lupus and mice with the Yaa allele, when activated with a number of stimuli. Our work demonstrates that: (1) resting B cells from mice containing the Yaa allele hyperproliferated compared to that seen with B cells from mice lacking the Yaa allele, (2) this hyperproliferation occurred whether cells were stimulated with phorbol myristate acetate/ionomycin, LPS, anti-IgM, or CD40L cross-linking, (3) this hyperproliferation is specific to B and not T cells. Taken together these data suggest that one mechanism by which the Yaa allele contributes to the accelerated onset of lupus in BXSB male mice is through its influence on B cell activation.

Alleles↗
PubMed1995

The IFN pregnancy recognition hormone IFN-tau blocks both development and superantigen reactivation of experimental allergic encephalomyelitis without associated toxicity.

Multiple sclerosis (MS) is an inflammatory demyelinating autoimmune disease if the central nervous system (CNS). Recently, the type I IFN, IFN-beta-1b was demonstrated to be a useful immunotherapy for MS. During treatment with IFN-beta-1b, toxicity at higher doses has been observed. IFN-tau, discovered for its role in the reproductive cycle, possesses all of the functions normally ascribed to the type I IFNs but lacks the toxicity normally associate with IFN treatment in vitro. We have examined the effects of IFN-tau treatment on experimental allergic encephalomyelitis (EAE), an animal model useful for the study of MS. EAE is a model of Ag-induced autoimmunity that can be modulated by bacterial superantigen to resemble the relapsing-remitting pattern of autoimmune disease observed in MS. IFN-tau was able to prevent development of EAE as effectively as IFN-beta but without associated toxicity such as lymphocyte suppression and weight loss. In addition, IFN-tau was able to prevent superantigen reactivation of EAE akin to the reduction in disease exacerbations observed in IFN-beta-1b treated MS patients. Mechanisms by which IFN-tau may prevent EAE include reduced proliferation in response to the autoantigen myelin basic protein and reduced TNF-alpha production. Thus, IFN-tau may prove to be a promising new IFN therapy for MS in light of its ability to prevent EAE and the lack of toxicity exhibited by this novel IFN.

Animals↗