Spontaneous Autoimmune Disease Research Articles

Deficiency in T follicular regulatory cells promotes autoimmunity.

T follicular regulatory (Tfr) cells are a new subset of regulatory T (T reg) cells localized in the germinal center to limit the humoral response. Until now, the physiological function of Tfr cells has been largely unknown. In this study, we developed a Bcl6fl/flFoxp3Cre mouse to analyze the function of Tfr cells in immune and autoimmune responses. These mice exhibited enhanced immunity to influenza virus; moreover, Bcl6fl/flFoxp3Cre/Cre mice developed late-onset spontaneous autoimmune diseases, affecting the salivary glands with lymphocyte infiltration and antibody deposition. In a mouse experimental Sjögren's syndrome model, ablation of Bcl6 in T reg cells greatly enhanced disease development. Conversely, Bcl6fl/flCd4Cre mice were protected in the model. Thus, our study indicates that Tfr cells control autoimmune diseases and can be targeted in infectious and autoimmune disease.

A Novel Pkhd1 Mutation Interacts with the Nonobese Diabetic Genetic Background To Cause Autoimmune Cholangitis.

We previously reported that NOD.c3c4 mice develop spontaneous autoimmune biliary disease (ABD) with anti-mitochondrial Abs, histopathological lesions, and autoimmune T lymphocytes similar to human primary biliary cholangitis. In this article, we demonstrate that ABD in NOD.c3c4 and related NOD ABD strains is caused by a chromosome 1 region that includes a novel mutation in polycystic kidney and hepatic disease 1 (Pkhd1). We show that a long terminal repeat element inserted into intron 35 exposes an alternative polyadenylation site, resulting in a truncated Pkhd1 transcript. A novel NOD congenic mouse expressing aberrant Pkhd1, but lacking the c3 and c4 chromosomal regions (NOD.Abd3), reproduces the immunopathological features of NOD ABD. RNA sequencing of NOD.Abd3 common bile duct early in disease demonstrates upregulation of genes involved in cholangiocyte injury/morphology and downregulation of immunoregulatory genes. Consistent with this, bone marrow chimera studies show that aberrant Pkhd1 must be expressed in the target tissue (cholangiocytes) and the immune system (bone marrow). Mutations of Pkhd1 produce biliary abnormalities in mice but have not been previously associated with autoimmunity. In this study, we eliminate clinical biliary disease by backcrossing this Pkhd1 mutation onto the C57BL/6 genetic background; thus, the NOD genetic background (which promotes autoimmunity) is essential for disease. We propose that loss of functional Pkhd1 on the NOD background produces early bile duct abnormalities, initiating a break in tolerance that leads to autoimmune cholangitis in NOD.Abd3 congenic mice. This model is important for understanding loss of tolerance to cholangiocytes and is relevant to the pathogenesis of several human cholangiopathies.

The transcription factor Ets1 cooperates with IL17 signaling to promote autoimmunity and immunodeficiency.

Abstract Ets1 is a lineage-specific transcription factor that regulates B and T cell functions in development and disease. Mice that lack Ets1 (Ets1 KO) develop spontaneous autoimmune disease with high levels of autoantibodies. Naïve CD4+ T cells isolated from Ets1 KO mice have differentiate more readily to Th17 cells and secrete IL-17, a cytokine extensively implicated in autoimmune disease pathogenesis. To determine if increased IL-17 production contributes to the development of autoimmunity in Ets1 KO mice, we generated Ets1/IL-17 Receptor double knock out (DKO) mice. We found that the absence of IL-17 signaling did not prevent or ameliorate the phenotype of Ets1 KO mice, but rather that DKO animals exhibited worse symptoms with striking increases in the numbers of Th2 cells and Tfh cells as well as germinal center B cells, isotype-switched B cells, memory B cells and plasma cells. Furthermore, DKO mice develop spontaneous skin lesions colonized by Staphylococcus aureus (S. aureus). When DKO mice were experimentally infected with S. aureus they were unable to clear the bacteria. Curiously, the increased bacterial susceptibility was age-dependent as 2 month old DKO mice were not susceptible, whereas 4 month old mice were. Our current model is that excessive immune activation over time leads to production of autoantibodies that target immune effector mechanisms important for anti-bacterial immunity, such as anti-microbial peptides, thereby resulting in susceptibility to S. aureus. Our studies may have important implications in understanding the mechanisms that drive pathogenesis in human diseases characterized by both autoimmunity and immunodeficiency.

Exacerbation of spontaneous autoimmune nephritis following regulatory T cell depletion in B cell lymphoma 2-interacting mediator knock-out mice.

Regulatory T cells (Tregs ) have been recognized as central mediators for maintaining peripheral tolerance and limiting autoimmune diseases. The loss of Tregs or their function has been associated with exacerbation of autoimmune disease. However, the temporary loss of Tregs in the chronic spontaneous disease model has not been investigated. In this study, we evaluated the role of Tregs in a novel chronic spontaneous glomerulonephritis model of B cell lymphoma 2-interacting mediator (Bim) knock-out mice by transient depleting Tregs . Bim is a pro-apoptotic member of the B cell lymphoma 2 (Bcl-2) family. Bim knock-out (Bim-/- ) mice fail to delete autoreactive T cells in thymus, leading to chronic spontaneous autoimmune kidney disease. We found that Treg depletion in Bim-/- mice exacerbated the kidney injury with increased proteinuria, impaired kidney function, weight loss and greater histological injury compared with wild-type mice. There was a significant increase in interstitial infiltrate of inflammatory cells, antibody deposition and tubular damage. Furthermore, the serum levels of cytokines interleukin (IL)-2, IL-4, IL-6, IL-10, IL-17α, interferon (IFN)-γ and tumour necrosis factor (TNF)-α were increased significantly after Treg depletion in Bim-/- mice. This study demonstrates that transient depletion of Tregs leads to enhanced self-reactive T effector cell function followed by exacerbation of kidney disease in the chronic spontaneous kidney disease model of Bim-deficient mice.

Formin like 1 expression is increased on CD4 + T lymphocytes in spontaneous autoimmune uveitis

The membrane protein expression repertoire of cells changes in course of activation. In equine recurrent uveitis (ERU), a spontaneous autoimmune disease in horses with relapsing and ultimately blinding inner eye inflammation, CD4+ T lymphocytes are the crucial pathogenic cells activated in the periphery directly prior to an inflammatory episode. In order to find relevant changes in the membrane proteome associated to disease, we sorted CD4+ lymphocytes and compared protein abundance from the generated proteome datasets of both healthy horses and ERU cases. We detected formin like 1, a key player in actin dependent cellular processes such as phagocytosis, cell adhesion and cell migration, with significantly higher abundance in the CD4+ cell membrane proteome of horses with ERU. In transmigration experiments, we demonstrated higher migration rate of cells originating from diseased animals connecting formin like 1 to the migratory ability of cells. These findings are the first description of formin like 1 in association to processes involved in migration of inflammatory CD4+ T cells across the blood-retinal barrier in a spontaneous ocular autoimmune disease and suggest formin like 1 to play a role in the molecular mechanisms of ERU disease pathogenesis.Data are available via ProteomeXchange with identifier PXD005384. Biological significanceThis comparative proteomic study of membrane proteins of CD4+ T cells identified a novel protein, formin like 1, with expression on the plasma cell membrane of equine CD4+ T cells and a significant change of abundance on CD4+ T cells of horses with a spontaneous autoimmune disease. Functional studies in a cell culture model for transmigration at the blood-retinal barrier (BRB) unraveled a strong impact of formin like 1 on migratory processes of CD4+ T cells across the BRB, a key event in uveitis pathogenesis. These findings provide novel knowledge about changes in the CD4+ immune cell membrane proteome in a spontaneously and naturally occurring autoimmune disease in horses with high relevance for veterinary medicine. Additionally, this model has proven translational quality for human medicine and provides novel proteomic information on autoimmune uveitis in man.

Quantitative PPARγ expression affects the balance between tolerance and immunity.

PPARγ modulates energy metabolism and inflammation. However, its specific functions in the balance of immunity in vivo have been explored incompletely. In this study, by the age of 14 mo, PpargC/− mice with PPARγ expression at 25% of the normal level exhibited high autoantibody levels and developed mesangial proliferative glomerulonephritis, which resembled systemic lupus erythematosus (SLE)-like autoimmune disease. These symptoms were preceded by splenomegaly at an early age, which was associated with increases in splenocyte accumulation and B-cell activation but not with relocation of hematopoiesis to the spleen. The mechanism of splenic lymphocyte accumulation involved reduced sphingosine-1-phosphate receptor 1 (S1P1) expression and diminished migration toward S1P in the PpargC/− splenocytes, which impeded lymphocyte egression. Mechanistically, increased Th17 polarization and IL-17 signaling in the PpargC/− CD4+ T cells contributed to B-cell hyperactivation in the spleen. Finally, the activation of the remaining PPARγ in PpargC/− mice by pioglitazone increased S1P1 levels, reduced the Th17 population in the spleen, and ameliorated splenomegaly. Taken together, our data demonstrated that reduction of Pparg expression in T-helper cells is critical for spontaneous SLE-like autoimmune disease development; we also revealed a novel function of PPARγ in lymphocyte trafficking and cross talk between Th17 and B cells.

Autologous Hematopoietic Stem Cell Transplantation (AHSCT) in Severe Auto-Immune Disease Adult Patients: Analysis of Outcomes from the French Society for Bone Marrow Transplantation and Cellular Therapy (SFGMT-TC) in Light of the European Society for Blood and Marrow Transplantation (EBMT) Activity

IntroductionAutologous Hematopoietic Stem Cell transplantation (AHSCT) is used since 1994 worldwide to treat severe autoimmune disease (AD) refractory to standard therapy. Despite early release and regular update of the European Society for Blood and Marrow Transplantation (EBMT) practice guidelines (Snowden JA et al BMT 2012, Alexander T et al BMT 2014) along with 3 randomised Clinical trials (CTs) for Systemic Sclerosis (SSc) ASTIS, Crohn's Disease (CD) ASTIC and Multiple sclerosis (MS) ASTIMS, the uptake of this approach varies according to each ADs and between countries. We therefore design this retrospective study to evaluate patients (pts) outcomes as reported to the French Bone Marrow Transplantation Society registry (SFGMT-TC) in light of the other States activity published or reported to the EBMTregistry.Materials and methodsAll AHSCT for adult AD pts (> 18 years (yrs)) reported in France from 1997 to 2013 with at least one yr follow-up after AHSCT were included in the study. Primary data were derived from the EBMT registry (MED-A/B forms) with additional data obtained through a specific questionnaire (MED-C) for the study. Primary end point is overall survival (OS), defined as time since the day of transplant to death, irrespective of the cause. Secondary end points are Progression Free Survival (PFS), 100 day treatment related mortality (100-day TRM) and non-relapse related mortality (NRM). The probabilities were estimated using the Kaplan-Meier estimator for OS and PFS, cumulative incidence for NRM, relapse/progression being the competing event. All tests were two-sided. Statistical analyses were performed with IBM SPSS Statistics 22.0 and R version 3.1.2 (R Development Core Team, Vienna, Austria) software packages.Results96 adult pts (55% Female), median age 45 yrs [20-71], underwent a first AHSCT for ADs in 19 HSCT Units. Most of the ADs were rheumatological(72%) with 55 SSc, 7 polymyositis-dermatomyositis, 3 polychondritis, 2 Lupus Erythematosus, 1 Rheumatoid Arthritis (RA), 1 Ankylosing Spondylitis, or neurological (15%) with 14 MS, whereas the others were 5 CDs, 5 immune thrombocytopenic purpura, 1 hemolytic autoimmune anemia, 1 IgM neuropathy and 1 POEMS syndrome. Two pts had 2 simultaneous ADs (1 SSc and RA, 1 CD and RA). Median duration between AD diagnosis and AHSCT was 3.5 yrs [1-33]. With a median follow-up of 7 yrs [<1- 17], 5 yrs OS and PFS were 79.4% [95% CI: 70.8-88] and 49.3% [95% CI: 38.7-59.9] while 10 yrs OS and PFS were 70.2% [95% CI: 58.9-81.7] and 41.9 % [95% CI: 30.6-53.2], respectively. The 100 days NRM was 7.4% [95% CI: 3.2-13.9]. 5 and 10 yrs NRM was 9.6% [95% CI: 4.7-16.6] and 13.6% [95% CI: 6.9-22.7] respectively. At the end of follow-up, 28 pts (29%) had died, for whom the causes of death were: relapse or progression (n=12), AHSCT related cause (n=7 with 3 infections, 2 cardiac toxicity, 1 renal toxicity, 1 respiratory failure), secondary malignancies (n=3), aspiration pneumonia in polychondritis (n=1) or unknown causes (n= 5).ConclusionAHSCT for severe ADs, has progressively developed in France, allowing 5y OS equal to 79.4%, similar to UK (Snowden JA et al, BJH 2012) and EBMT data. In rapidly progressive severe SSc, where the proof of efficacy of AHSCT was obtained (Van Laar J and Farge D et al, JAMA 2014) and in MS (Pasquini MC et al BBMT 2010) where long-term responses are confirmed worldwide, the French and the EBMT registry activities have increased over the past 14 years, with sustained positive clinical results despite non negligible NMR, which remains lower than spontaneous AD evolution. Meanwhile, AHSCT activity has become exceptional in RA due to the availability of safe and effective biological therapies, and other indications remain rare, such as for CD or SLE where the risk of AHSCT in highly immunosuppressed patients has to be balanced with ADs severity. More than half of French pts were treated on an individual basis, outside CTs, underlying the need to evaluate national activity and to promote education of HSCT Unit members. At each French or other European state levels, like in the US, the indications for AHSCT in ADs remain low due to other competing therapies. Combined study using European and American data registry will allow analysis of a larger number of AD pts treated by AHSCT and would offer more clues to better understand the determinants of the response and to refine indications for each AD type. DisclosuresLeblond:Gilead: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Roche: Consultancy, Honoraria, Other: Travel, Accommodations, Expenses, Speakers Bureau; GSK: Consultancy, Honoraria, Speakers Bureau; Mundipharma: Honoraria. Snowden:MSD: Consultancy, Other: Educational support, Speakers Bureau; Janssen: Other: Educational support, Speakers Bureau; Celgene: Other: Educational support, Speakers Bureau; Sanofi: Consultancy.

IL-3 contributes to development of lupus nephritis in MRL/Ipr mice

MRL/lpr mice develop a spontaneous autoimmune disease that closely resembles human systemic lupus erythematosus (SLE) with DNA autoantibodies, hypergammaglobulinemia, immune complex glomerulonephritis, and systemic vasculitis. Little is known about the role of IL-3 in SLE. In order to study this we analyzed the expression of IL-3 in murine lupus and determined whether blockade of IL-3 with a monoclonal antibody or injection of recombinant IL-3 affects lupus nephritis in MRL/lpr mice. During disease progression IL-3 levels were increased in the plasma and in the supernatant of cultured splenocytes from MRL/lpr mice. Administration of IL-3 aggravated the disease with significantly higher renal activity scores, more renal fibrosis, and more glomerular leukocyte infiltration and IgG deposition. Blockade of IL-3 significantly improved acute and chronic kidney damage, reduced the glomerular infiltration of leukocytes and the glomerular deposition of IgG, and decreased the development of renal fibrosis. Furthermore, DNA autoantibody production, proteinuria, and serum creatinine levels were significantly lower in the anti-IL-3 group. Thus, IL-3 plays an important role in the pathogenesis of SLE and the progression of lupus nephritis. Hence, blockade of IL-3 may represent a new strategy for treatment of lupus nephritis.

BIM Deficiency Protects NOD Mice From Diabetes by Diverting Thymocytes to Regulatory T Cells.

Because regulatory T-cell (Treg) development can be induced by the same agonist self-antigens that induce negative selection, perturbation of apoptosis will affect both negative selection and Treg development. But how the processes of thymocyte deletion versus Treg differentiation bifurcate and their relative importance for tolerance have not been studied in spontaneous organ-specific autoimmune disease. We addressed these questions by removing a critical mediator of thymocyte deletion, BIM, in the NOD mouse model of autoimmune diabetes. Despite substantial defects in the deletion of autoreactive thymocytes, BIM-deficient NOD (NODBim(-/-)) mice developed less insulitis and were protected from diabetes. BIM deficiency did not impair effector T-cell function; however, NODBim(-/-) mice had increased numbers of Tregs, including those specific for proinsulin, in the thymus and peripheral lymphoid tissues. Increased levels of Nur77, CD5, GITR, and phosphorylated IκB-α in thymocytes from NODBim(-/-) mice suggest that autoreactive cells receiving strong T-cell receptor signals that would normally delete them escape apoptosis and are diverted into the Treg pathway. Paradoxically, in the NOD model, reduced thymic deletion ameliorates autoimmune diabetes by increasing Tregs. Thus, modulating apoptosis may be one of the ways to increase antigen-specific Tregs and prevent autoimmune disease.

B cell abnormalities in a mouse model of SLE

Event Abstract Back to Event B cell abnormalities in a mouse model of SLE Camila Fuentes1, Natalia Crisostomo1, María A. Gleisner2, 3, Mario Rosemblatt1, 4 and Maria R. Bono1* 1 Laboratorio de Inmunología, Facultad de Ciencias, Universidad de Chile, Chile 2 Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Chile 3 Instituto Milenio de Inmunología e Inmunoterapia, Universidad de Chile, Chile 4 Fundación Ciencia & Vida, Chile Systemic lupus erythematosus (SLE) is an autoimmune disease of unknown etiology characterized by the activation of autoreactive T and B cells, autoantibody production and immune complex deposition causing damage in multiple tissues. B cells play a critical role in the development of SLE. Besides the production of auto-antibodies, it has been described that B cells have the ability to produce cytokines and present antigens, which allows them to have different roles during the immune response. Using a spontaneous autoimmune disease setting, (NZWxNZB) F1 (BWF1) mice, that develops SLE at the age of 6 months, characterized by high proteinuria levels and serum autoantibody titers, we analyzed different B cell subpopulations such as regulatory and memory populations through flow cytometry (FACS) using specific B cell markers. Important differences were seen on the regulatory B cells populations, plasma cells and B10 cells which were increased on spleen of BWF1 aged autoimmune mice. We also studied the effect of dendritic cells (DCs) in vivo over B cells and their participation in the development of the disease. Two doses of DCs from BWF1 aged autoimmune mice were transferred onto BWF1 young pre-autoimmune mice. Two months after the adoptive transfer of DCs, mice were sacrificed and B cells were studied by FACS analysis. Our results showed that the adoptive transfer of DCs from BWF1 aged autoimmune mice into BWF1 young pre-autoimmune mice promoted an accelerated and exacerbated humoral response comparable to that seen on the normal development of SLE. Thus, treatment with DCs from BWF1 aged autoimmune mice caused significant changes in the phenotype and distribution of B cells from BWF1 young pre-autoimmune mice, similar to what we see on BWF1 aged autoimmune mice, indicating that the interaction between B cells and DCs maybe determining in the development of the disease. Acknowledgements Funded by FONDECYT 1100557, PFB-16. Keywords: Lupus Erythematosus, Systemic, B cells, Dendritic Cells, Autoimmune Diseases, Autoantibodies Conference: IMMUNOCOLOMBIA2015 - 11th Congress of the Latin American Association of Immunology - 10o. Congreso de la Asociación Colombiana de Alergia, Asma e Inmunología, Medellin, Colombia, 13 Oct - 16 Oct, 2015. Presentation Type: Poster Presentation Topic: Autoimmunity Citation: Fuentes C, Crisostomo N, Gleisner MA, Rosemblatt M and Bono MR (2015). B cell abnormalities in a mouse model of SLE. Front. Immunol. Conference Abstract: IMMUNOCOLOMBIA2015 - 11th Congress of the Latin American Association of Immunology - 10o. Congreso de la Asociación Colombiana de Alergia, Asma e Inmunología. doi: 10.3389/conf.fimmu.2015.05.00207 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 14 Apr 2015; Published Online: 14 Sep 2015. * Correspondence: Prof. Maria R Bono, Laboratorio de Inmunología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile, mrbono@uchile.cl Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Camila Fuentes Natalia Crisostomo María A Gleisner Mario Rosemblatt Maria R Bono Google Camila Fuentes Natalia Crisostomo María A Gleisner Mario Rosemblatt Maria R Bono Google Scholar Camila Fuentes Natalia Crisostomo María A Gleisner Mario Rosemblatt Maria R Bono PubMed Camila Fuentes Natalia Crisostomo María A Gleisner Mario Rosemblatt Maria R Bono Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

De-functioning polymorphism in the inhibitory receptor FcγRIIB does not impact upon kidney allograft survival.

De-functioning polymorphism in the inhibitory receptor FcγRIIB does not impact upon kidney allograft survival.

Reduction of T cell receptor diversity in NOD mice prevents development of type 1 diabetes but not Sjögren's syndrome.

Non-obese diabetic (NOD) mice are well-established models of independently developing spontaneous autoimmune diseases, Sjögren’s syndrome (SS) and type 1 diabetes (T1D). The key determining factor for T1D is the strong association with particular MHCII molecule and recognition by diabetogenic T cell receptor (TCR) of an insulin peptide presented in the context of I-Ag7 molecule. For SS the association with MHCII polymorphism is weaker and TCR diversity involved in the onset of the autoimmune phase of SS remains poorly understood. To compare the impact of TCR diversity reduction on the development of both diseases we generated two lines of TCR transgenic NOD mice. One line expresses transgenic TCRβ chain originated from a pathogenically irrelevant TCR, and the second line additionally expresses transgenic TCRαmini locus. Analysis of TCR sequences on NOD background reveals lower TCR diversity on Treg cells not only in the thymus, but also in the periphery. This reduction in diversity does not affect conventional CD4+ T cells, as compared to the TCRmini repertoire on B6 background. Interestingly, neither transgenic TCRβ nor TCRmini mice develop diabetes, which we show is due to lack of insulin B:9–23 specific T cells in the periphery. Conversely SS develops in both lines, with full glandular infiltration, production of autoantibodies and hyposalivation. It shows that SS development is not as sensitive to limited availability of TCR specificities as T1D, which suggests wider range of possible TCR/peptide/MHC interactions driving autoimmunity in SS.

Development of an autoimmune syndrome affecting the skin and internal organs in P-selectin glycoprotein ligand 1 leukocyte receptor-deficient mice.

To define and characterize the progression of the spontaneous autoimmune disease that develops in mice in the absence of the leukocyte adhesion receptor P-selectin glycoprotein ligand 1 (PSGL-1). Skin-resident immune cells from PSGL-1-deficient mice and C57BL/6 control mice of different ages were isolated and analyzed by flow cytometry. Biochemical parameters were analyzed in mouse serum and urine, and the presence of serum autoantibodies was investigated. Skin and internal organs were extracted, and their structure was analyzed histologically. Skin-resident innate and adaptive immune cells from PSGL-1(-/-) mice had a proinflammatory phenotype with an imbalanced T effector cell:Treg cell ratio. Sera from PSGL-1(-/-) mice had circulating autoantibodies commonly detected in connective tissue-related human autoimmune diseases. Biochemical and histologic analysis of skin and internal organs revealed skin fibrosis and structural and functional abnormalities in the lungs and kidneys. Furthermore, PSGL-1(-/-) mice exhibited vascular alterations, showing loss of dermal vessels, small vessel medial layer remodeling in the lungs and kidneys, and ischemic processes in the kidney that promote renal infarcts. Our study demonstrates that immune system overactivation due to PSGL-1 deficiency triggers an autoimmune syndrome with characteristics similar to systemic sclerosis, including skin fibrosis, vascular alterations, and systemic organ involvement. These results suggest that PSGL-1 expression contributes to the maintenance of the homeostasis of the immune system and could act as a barrier for autoimmunity in mice.

Myelin-specific antibodies trigger spontaneous CNS autoimmune disease in the absence of myelin-specific B cells

Myelin-specific antibodies trigger spontaneous CNS autoimmune disease in the absence of myelin-specific B cells

S-1: Regnase-1, a ribonuclease involved in the inflammatory and immune responses

Gene expression is controlled at multiple points, including signal transduction, transcription and mRNA stability. So far, transcriptional regulation has been extensively studied. However, recent studies have revealed that control of gene expression at the mRNA level is as important as transcriptional control in the immune response. The innate immune system is an evolutionally conserved host defense mechanism against pathogens. Innate immune responses are initiated by activation of pattern recognition receptors (PRRs), which recognize microbial components. Among them, Toll-like receptors (TLRs) are capable of sensing organisms ranging from bacteria to fungi, protozoa and viruses, and play a major role in innate immunity. Individual TLRs recognize different microbial components, activate different signaling pathways via selective usage of adaptor molecules, and give rise to different patterns in gene expression. We are now focusing on the role of genes induced in response to TLR stimulation, particularly the genes that are rapidly induced in a MyD88-dependent manner within 30 min after LPS stimulation. Among them, we have recently identified a novel gene named Zc3h12a which has a CCCH-type zinc finger domain. The knockout mice developed spontaneous autoimmune diseases accompanied by splenomegaly and lymphadenopathy. Subsequent studies showed that Zc3h12a is a nuclease involved in destabilization of IL-6 and IL-12mRNA via the stem loop structure present in the 3’UTR of these genes. We renamed it Regulatory RNase-1 (Regnase-1) based on the function. I would like to discuss the role of Regnase-1 in the immune response.

New insights into disease-specific absence of complement factor H related protein C in mouse models of spontaneous autoimmune diseases

Complement factor H (CFH) protein is an inhibitor of the alternative pathway of complement (AP) both in the fluid phase and on the surface of host cells. Mouse and human complement factor H-related (CFHR) proteins also belong to the fH family of plasma glycoproteins. The main goal of the current study was to compare the presence of mRNA for two mCFHR proteins in spontaneously developing autoimmune diseases in mice such as dense deposit disease (DDD), diabetes mellitus (DM), basal laminar deposits (BLD), collagen antibody-induced arthrits (CAIA) and systemic lupus erythematosus (SLE). Here we report for the first time that the CFHR-C mRNA was universally absent in the liver from three strains of lupus-prone mice and in a diabetic-prone mouse strain. The mRNA levels (pg/ng) for CFH and CFHR-B in MRL-lpr/lpr, at 9wks and 23wks were 707.2±44.4, 54.5±5.75 and 729±252.9, 74.04±22.76, respectively. The mRNA levels for CFH and CFHR-B in NZB/NZW mice, at 9wks and 54wks were 579.9±23.8, 58.8±1.41 and 890.3±135.2, 63.30±9.2, respectively. CFHR-C protein was absent in the circulation of MRL-lpr/lpr and NZB/NZW mice before and after the development of lupus. Similarly, mRNA and protein for CFHR-C was universally absent in liver and other organs and in the circulation of NOD mice before and after the development of DM. In contrast, the mRNAs for CFH, CFHR-B and CFHR-C were universally present in the liver from mice with and without DDD, BLD and CAIA. The levels of mRNA for CFHR-B in mice with and without BLD were ∼4 times higher than the mice with lupus. The complete absence of mRNA for CFHR-C in lupus and diabetic-prone strains indicates that polymorphic variation within the mouse CFHR family exists and raises the possibility that such variation contributes to lupus and diabetic phenotypes.

In situ cell surface proteomics reveals differentially expressed membrane proteins in retinal pigment epithelial cells during autoimmune uveitis.

We applied an innovative and successful method to detect changes in the plasma cell surface proteome of RPE cells in a spontaneous inflammatory eye disease, serving as a valuable model for human autoimmune uveitis. We were able to identify 27 differentially expressed plasma cell membrane proteins, including synaptotagmin 1, basigin and collectrin, which play important roles in cell adhesion, transport and cell communication.

Dysregulated CD8+ T cells promote B cell activation and antibody-mediated autoimmune disease (BA2P.123)

Abstract IFNγ-producing CD4 and CD8 T cells accumulate during autoimmune disease in IL-2-KO mice. CD4 T cells are necessary for disease progression, and we have previously shown that IL-2-KO CD4 T cells can transfer autoimmunity. However, the importance of CD8 T cells to initiation and propagation of disease is unclear. Several groups have demonstrated a protective role for CD8 T cells in inflammation and autoimmunity, while others have suggested a pathogenic role. To define the function of CD8 T cells during spontaneous autoimmune disease, we depleted CD8 T cells in IL-2-KO mice and evaluated the pathogenesis of autoimmunity. Elimination of CD8 T cells for only two weeks resulted in a significant augmentation of survival, reduction in the number and activation state of the CD4 T cells and B cells, and a delay in the development of RBC-specific antibodies. In untreated IL-2-KO mice, both CD4+ and CD8 T cells produced IFNγ in response to RBC antigens, indicating that RBC-specific CD8 T cells are present during disease. Our results suggest that autoreactive CD8 T cells contribute to the initiation or propagation of lymphoproliferation and autoimmunity. We are addressing the relative importance of autoreactive CD8 T cells to that of the CD4 T cells, and are evaluating the mechanisms by which CD8 T cells influence the autoimmune disease process. Early data indicate that IL-2-KO CD8 T cells produce elevated levels of perforin, granzyme B, and IFNγ, and induce B cell proliferation.

Culture promotes transfer of thyroid epithelial cell hyperplasia and proliferation by reducing regulatory T cell numbers

IFN-γ−/− NOD.H-2h4 mice develop a spontaneous autoimmune thyroid disease, thyroid epithelial cell hyperplasia and proliferation (TEC H/P) when given NaI in their water for 7+ mo. TEC H/P can be transferred to IFN-γ−/− SCID mice by splenocytes from mice with severe (4–5+) disease, and transfer of TEC H/P is improved when splenocytes are cultured prior to transfer. Older (9+ mo) IFN-γ−/− NOD.H-2h4 mice have elevated numbers of FoxP3+ T reg cells, up to 2-fold greater than younger (2 mo) mice. During culture, the number of T reg decreases and this allows the improved transfer of TEC H/P. Co-culture with IL-2 prior to transfer prevents the decrease of T reg and improves their in vitro suppressive ability resulting in reduced TEC H/P in recipient mice. Therefore, culturing splenocytes improves transfer of TEC H/P by reducing the number of T reg and IL-2 inhibits transfer by preserving T reg number and function.

Breakdown of immune privilege and spontaneous autoimmunity in mice expressing a transgenic T cell receptor specific for a retinal autoantigen

Despite presence of circulating retina-specific T cells in healthy individuals, ocular immune privilege usually averts development of autoimmune uveitis. To study the breakdown of immune privilege and development of disease, we generated transgenic (Tg) mice that express a T cell receptor (TCR) specific for interphotoreceptor retinoid-binding protein (IRBP), which serves as an autoimmune target in uveitis induced by immunization. Three lines of TCR Tg mice, with different levels of expression of the transgenic R161 TCR and different proportions of IRBP-specific CD4+ T cells in their peripheral repertoire, were successfully established. Importantly, two of the lines rapidly developed spontaneous uveitis, reaching 100% incidence by 2 and 3 months of age, respectively, whereas the third appeared “poised” and only developed appreciable disease upon immune perturbation. Susceptibility roughly paralleled expression of the R161 TCR. In all three lines, peripheral CD4+ T cells displayed a naïve phenotype, but proliferated in vitro in response to IRBP and elicited uveitis upon adoptive transfer. In contrast, CD4+ T cells infiltrating uveitic eyes mostly showed an effector/memory phenotype, and included Th1, Th17 as well as T regulatory cells that appeared to have been peripherally converted from conventional CD4+ T cells rather than thymically derived. Thus, R161 mice provide a new and valuable model of spontaneous autoimmune disease that circumvents the limitations of active immunization and adjuvants, and allows to study basic mechanisms involved in maintenance and breakdown of immune homeostasis affecting immunologically privileged sites such as the eye.