A humanized model of experimental autoimmune uveitis in HLA class II transgenic mice

Pathogenesis and current therapies for non-infectious uveitis

Non-infectious uveitis (NIU) is a disorder with various etiologies and is characterized by eye inflammation, mainly affecting people of working age. An accurate diagnosis of NIU is crucial for appropriate therapy. The aim of therapy is to improve vision, relieve ocular inflammation, prevent relapse, and avoid treatment side effects. At present, corticosteroids are the mainstay of topical or systemic therapy. However, repeated injections are required for the treatment of chronic NIU. Recently, new drug delivery systems that may ensure intraocular delivery of therapeutic drug levels have been highlighted. Furthermore, with the development of immunosuppressants and biologics, specific therapies can be selected based on the needs of each patient. Immunosuppressants used in the treatment of NIU include calcineurin inhibitors and antimetabolites. However, systemic immunosuppressive therapy itself is associated with adverse effects due to the inhibition of immune function. In patients with refractory NIU or those who cannot tolerate corticosteroids and immunosuppressors, biologics have emerged as alternative treatments. Thus, to improve the prognosis of patients with NIU, NIU should be managed with different drugs according to the response to treatment and possible side effects.

Multimodal evaluation of an interphotoreceptor retinoid-binding protein-induced mouse model of experimental autoimmune uveitis

We aimed to characterize the vascular phenotypes of an experimental autoimmune retinal uveitis (EAU) model induced by interphotoreceptor retinoid-binding protein (IRBP) using multimodal imaging techniques. We systemically administered IRBP or vehicle to adult C57BL/6 mice. Fundus photography, optical coherence tomography (OCT), in vivo live confocal imaging using different tracers, OCT angiography (OCTA), and electroretinography (ERG) were performed after IRBP immunization. Hematoxylin and eosin and immunofluorescence staining were performed to characterize the immune response and vascular permeability. Mice with EAU exhibited perivascular inflammation, vitritis, and superficial retinal inflammation on fundus photography and OCT. H&E revealed immune cell infiltration in the perivascular area of the retina and choroid accompanied by a significant degree of perivasculitis that subsequently damaged photoreceptors 3 weeks postimmunization. Immunofluorescence staining showed subsequent transcytosis induction after local microglial activation followed by neutrophil recruitment in the perivascular area. Transcytosis in the superficial and deep vascular areas was improved by immune cell suppression. Intravital in vivo confocal imaging showed signs of neutrophil infiltration and obstructive vasculitis with perivascular leakage 3 weeks postimmunization. OCTA revealed a significant decrease in vascular flow in the deep capillary layer of the retina. Functional analysis showed that scotopic responses were intact at 2 weeks; however, normal photopic and scotopic responses were hardly detected in mice with EAU mice at 3 weeks postimmunization. Our data suggest that inflammatory cell activation and subsequent transcytosis induction in endothelial cells might be a major pathogenic factor for vascular leakage in uveitis, providing new insights into the pathophysiology of retinal vasculitis in noninfectious uveitis.

Studying a mouse model of autoimmune uveitis, a damaging form of eye inflammation affecting the retina and choroid of the eye, reveals new cellular and molecular details of how blood vessel inflammation can damage the retina. Researchers in South Korea and Japan led by Joo Yong Lee at the University of Ulsan, Seoul, initiated autoimmune uveitis in mice by administering retinoid-binding protein, which is known to stimulate autoimmune changes which model aspects of the human disease. Their work revealed that the inflammation caused by the autoimmune response makes the blood vessels supplying the retina more permeable to a variety of large molecules. This increased permeability, due to a membrane transport process called transcytosis, was preceded by specific cellular changes. This deeper understanding of the pathology of uveitis could help research towards new treatments.

Therapeutic Effect of IL-38 on Experimental Autoimmune Uveitis: Reprogrammed Immune Cell Landscape and Reduced Th17 Cell Pathogenicity

Purpose

The purpose of this study was to elucidate the effects of interleukin (IL)-38 on experimental autoimmune uveitis (EAU) and its underlying mechanisms.

Methods

Mice with EAU were treated with IL-38, and the retinas and cervical draining lymph nodes (CDLNs) were analyzed by flow cytometry. Single-cell RNA sequencing (scRNA-seq) was conducted to analyze the immune cell profiles of CDLNs from normal, EAU, and IL-38-treated mice.

Results

Administration of IL-38 attenuated EAU symptoms and reduced the proportion of T helper 17 (Th17) and T helper 1 (Th1) cells in the retinas and CDLNs. In scRNA-seq analysis, IL-38 downregulated the IL-17 signaling pathway and reduced the expression of Th17 cell pathogenicity-related genes (Csf2 and Il23r), findings which were also confirmed by flow cytometry. In vitro, IL-38 reduced the granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulation function of IL-23 and inhibited IL-23R expression in Th17 cells. Moreover, when co-cultured with Th17 cells, IL-38 prevented IL-23 production in antigen-presenting cells (APCs).

Conclusions

Our data demonstrate the therapeutic effect of IL-38 on EAU, and suggest that the effect of IL-38 may be caused by dampening of the GM-CSF/IL-23R/IL-23 feedback loop between Th17 cells and APCs.

Aging weakens Th17 cell pathogenicity and ameliorates experimental autoimmune uveitis in mice

Aging-induced changes in the immune system are associated with a higher incidence of infection and vaccination failure. Lymph nodes, which filter the lymph to identify and fight infections, play a central role in this process. However, careful characterization of the impact of aging on lymph nodes and associated autoimmune diseases is lacking. We combined single-cell RNA sequencing (scRNA-seq) with flow cytometry to delineate the immune cell atlas of cervical draining lymph nodes (CDLNs) of both young and old mice with or without experimental autoimmune uveitis (EAU). We found extensive and complicated changes in the cellular constituents of CDLNs during aging. When confronted with autoimmune challenges, old mice developed milder EAU compared to young mice. Within this EAU process, we highlighted that the pathogenicity of T helper 17 cells (Th17) was dampened, as shown by reduced GM-CSF secretion in old mice. The mitigated secretion of GM-CSF contributed to alleviation of IL-23 secretion by antigen-presenting cells (APCs) and may, in turn, weaken APCs’ effects on facilitating the pathogenicity of Th17 cells. Meanwhile, our study further unveiled that aging downregulated GM-CSF secretion through reducing both the transcript and protein levels of IL-23R in Th17 cells from CDLNs. Overall, aging altered immune cell responses, especially through toning down Th17 cells, counteracting EAU challenge in old mice.

The Role of Retinal Pigment Epithelial Cells in Regulation of Macrophages/Microglial Cells in Retinal Immunobiology

The ocular tissue microenvironment is immune privileged and uses several mechanisms of immunosuppression to prevent the induction of inflammation. Besides being a blood-barrier and source of photoreceptor nutrients, the retinal pigment epithelial cells (RPE) regulate the activity of immune cells within the retina. These mechanisms involve the expression of immunomodulating molecules that make macrophages and microglial cells suppress inflammation and promote immune tolerance. The RPE have an important role in ocular immune privilege to regulate the behavior of immune cells within the retina. Reviewed is the current understanding of how RPE mediate this regulation and the changes seen under pathological conditions.

Blocking the inflammasome: A novel approach to treat uveitis

Uveitis is a complex ocular inflammatory disease often accompanied by bacterial or viral infections (infectious uveitis) or underlying autoimmune diseases (non-infectious uveitis). Treatment of the underlying infection along with corticosteroid-mediated suppression of acute inflammation usually resolves infectious uveitis. However, to develop more effective therapies for non-infectious uveitis and to better address acute inflammation in infectious disease, an improved understanding of the underlying inflammatory pathways is needed. In this review, we discuss the disease aetiology, preclinical in vitro and in vivo uveitis models, the role of inflammatory pathways, as well as current and future therapies. In particular, we highlight the involvement of the inflammasome in the development of non-infectious uveitis and how it could be a future target for effective treatment of the disease.

A Review of the Various Roles and Participation Levels of B-Cells in Non-Infectious Uveitis

Non-infectious uveitis is an inflammatory disorder of the eye that accounts for severe visual loss without evident infectious agents. While T cells are supposed to dominate the induction of inflammation in non-infectious uveitis, the role of B cells in the pathogenesis of this disease is obscure. Therefore, this review aimed to discuss diverse B-cell participation in different non-infectious uveitides and their roles in the pathogenesis of this disease as well as the mechanism of action of rituximab. Increasing evidence from experimental models and human non-infectious uveitis has suggested the participation of B cells in non-infectious uveitis. The participation levels vary in different uveitides. Furthermore, B cells play multiple roles in the pathogenic mechanisms. B cells produce autoantibodies, regulate T cell responses via antibody-independent functions, and constitute ectopic lymphoid structures. Regulatory B cells perform pivotal anti-inflammatory functions in non-infectious uveitis. Rituximab may work by depleting pro-inflammatory B cells and restoring the quantity and function of regulatory B cells in this disease. Identifying the levels of B-cell participation and the associated roles is beneficial for optimizing therapy. Diversified experimental model choices and emerging tools and/or methods are conducive for future studies on this topic.

HLA transgenic mice: application in reproducing idiosyncratic drug toxicity

Various types of transgenic mice carrying either class I or II human leukocyte antigen (HLA) molecules are readily available, and reports describing their use in a variety of studies have been published for more than 30 years. Examples of their use include the discovery of HLA-specific antigens against viral infection as well as the reproduction of HLA-mediated autoimmune diseases for the development of therapeutic strategies. Recently, HLA transgenic mice have been used to reproduce HLA-mediated idiosyncratic drug toxicity (IDT), a rare and unpredictable adverse drug reaction that can result in death. For example, abacavir-induced IDT has successfully been reproduced in HLA-B*57:01 transgenic mice. Several reports using HLA transgenic mice for IDT have proven the utility of this concept for the evaluation of IDT using various HLA allele combinations and drugs. It has become apparent that such models may be a valuable tool to investigate the mechanisms underlying HLA-mediated IDT. This review summarizes the latest findings in the area of HLA transgenic mouse models and discusses the current challenges that must be overcome to maximize the potential of this unique animal model.

Comprehensive analysis of a mouse model of spontaneous uveoretinitis using single-cell RNA sequencing

Autoimmune uveoretinitis is a significant cause of visual loss, and mouse models offer unique opportunities to study its disease mechanisms. Aire ^-/- mice fail to express self-antigens in the thymus, exhibit reduced central tolerance, and develop a spontaneous, chronic, and progressive uveoretinitis. Using single-cell RNA sequencing (scRNA-seq), we characterized wild-type and Aire ^-/- retinas to define, in a comprehensive and unbiased manner, the cell populations and gene expression patterns associated with disease. Based on scRNA-seq, immunostaining, and in situ hybridization, we infer that 1) the dominant effector response in Aire ^-/- retinas is Th1-driven, 2) a subset of monocytes convert to either a macrophage/microglia state or a dendritic cell state, 3) the development of tertiary lymphoid structures constitutes part of the Aire ^-/- retinal phenotype, 4) all major resident retinal cell types respond to interferon gamma (IFNG) by changing their patterns of gene expression, and 5) Muller glia up-regulate specific genes in response to IFN gamma and may act as antigen-presenting cells.

Identification of Ocular Autoantigens Associated With Juvenile Idiopathic Arthritis-Associated Uveitis

The purpose of the current study was to analyze the binding patterns of serum autoantibodies from juvenile idiopathic arthritis (JIA) and JIA-associated uveitis (JIAU) patients to proteomes from different ocular tissues and to identify potential ocular autoantigens in JIAU. Proteomes from porcine iris, ciliary body, or retina tissue were isolated, separated using 2D-gel electrophoresis, and transferred to a blotting membrane. The binding pattern of serum antibodies from JIA or JIAU patients or healthy controls to ocular proteins was visualized by using anti-human IgG secondary antibodies and chemiluminescence reaction. Selected protein spots were excised from silver-stained 2D gels and subjected to mass spectrometry. Serum antibodies binding to ocular proteins were detected in all patient groups and healthy controls. Irrespective of the patient groups, serum antibodies bound to 49 different protein spots of the retina proteome, to 53 of the ciliary body proteome, and to 44 of the iris proteome. The relative binding frequency of sera to these iris protein spots was significantly higher in JIAU than in JIA patients or healthy controls. Particularly in JIAU patients, cluster analyses indicated a broad range of serum antibodies directed against ocular antigens, mostly in the iris proteome. Iris proteins frequently bound by serum antibodies in all groups were identified as tubulin beta chain, vimentin, ATP synthase subunit beta, actin, and L-lactate dehydrogenase B chain. Iris proteins exclusively bound by JIAU serum antibodies were heat shock cognate 71 kDa protein and keratin. Although serum autoantibody binding to ocular antigens was not disease-specific, a significant diversity of autoantibodies against a broad range of antigens, particularly from the iris tissue, was detected in JIAU patients. As the iris is a major site of inflammation in JIAU, the present data give further evidence that autoantibodies may be involved in JIAU immunopathology.

Automated three-dimensional cell counting method for grading uveitis of rodent eye in vivo with optical coherence tomography

In preclinical vision research, cell grading in small animal models is essential for the quantitative evaluation of intraocular inflammation. Here, we present a new and practical optical coherence tomography (OCT) image analysis method for the automated detection and counting of aqueous cells in the anterior chamber (AC) of a rodent model of uveitis. Anterior segment OCT images are acquired with a 100 kHz swept-source OCT system. The proposed method consists of 2 steps. In the first step, we first despeckle and binarize each OCT image. After removing AS structures in the binary image, we then apply area thresholding to isolate cell-like objects. Potential cell candidates are selected based on their best fit to roundness. The second step performs the cell counting within the whole AC, in which additional cell tracking analysis is conducted on the successive OCT images to eliminate redundancy in cell counting. Finally, 3D cell grading using the proposed method is demonstrated in longitudinal OCT imaging of a mouse model of anterior uveitis in vivo. Rendering of anterior segment (orange) of mouse eye and automatically counted anterior chamber cells (green). Inset is a top view of the rendering, showing the cell distribution across the anterior chamber.

Gut microbiota as a source of a surrogate antigen that triggers autoimmunity in an immune privileged site

Recent discoveries on the role of commensal microbiota have significantly changed our understanding of human physiology. The host-microbiota interplay is now an important aspect to take into account to understand immune responses and immunological diseases. Autoimmune uveitis is a sight-threatening disease that arises without a known infectious etiology. It is unknown where and how autoreactive T cells become primed to trigger disease in the eye, which is an immune privileged site. We recently reported data supporting the notion that retina-specific T cells receive a signal in the gut from commensal microbiota-derived cross-reactive antigen(s) and trigger autoimmune uveitis in the R161H mouse model. Here we discuss our published findings, as well as our recent attempts to identify the responsible microbe(s) by using different antibiotic treatments, 16S rDNA sequencing and homology searches for candidate antigenic mimic(s) of the retinal antigen.

Experimental autoimmune uveitis and other animal models of uveitis: An update

Over the past several decades, animal models of autoimmune uveitis directed at eye-specific antigens (Ags) have been developed. These have allowed researchers to understand the basic mechanisms that lead to these diseases and also recently helped the researchers in translational research for therapeutic interventions. Experimental autoimmune uveitis (EAU) is an animal disease model of human endogenous uveitis and can be induced in susceptible animals by immunization with retinal Ags. Ever since the first description of EAU in mice in 1988, several animal models of uveitis has been described by researchers. Disease-specific model for cytomegalovirus retinitis and tubercular uveitis has evolved our understanding of these complex entities. Endotoxin induced uveitis is another useful model for anterior uveitis, which is not an autoimmune process and is triggered by injection of bacterial endotoxin (lipopolysaccharides) resulting in a rapid short lasting uveitis. The current article will give an insight into the various EAU animal models and their current implications in translational research. The article will also highlight the different grading systems for EAU in the animal model.

Involvement of B cells in non-infectious uveitis

Non-infectious uveitis-or intraocular inflammatory disease-causes substantial visual morbidity and reduced quality of life amongst affected individuals. To date, research of pathogenic mechanisms has largely been focused on processes involving T lymphocyte and/or myeloid leukocyte populations. Involvement of B lymphocytes has received relatively little attention. In contrast, B-cell pathobiology is a major field within general immunological research, and large clinical trials have showed that treatments targeting B cells are highly effective for multiple systemic inflammatory diseases. B cells, including the terminally differentiated plasma cell that produces antibody, are found in the human eye in different forms of non-infectious uveitis; in some cases, these cells outnumber other leukocyte subsets. Recent case reports and small case series suggest that B-cell blockade may be therapeutic for patients with non-infectious uveitis. As well as secretion of antibody, B cells may promote intraocular inflammation by presentation of antigen to T cells, production of multiple inflammatory cytokines and support of T-cell survival. B cells may also perform various immunomodulatory activities within the eye. This translational review summarizes the evidence for B-cell involvement in non-infectious uveitis, and considers the potential contributions of B cells to the development and control of the disease. Manipulations of B cells and/or their products are promising new approaches to the treatment of non-infectious uveitis.

Tertiary Lymphoid Tissue Forms in Retinas of Mice with Spontaneous Autoimmune Uveitis and Has Consequences on Visual Function

During chronic inflammation, tertiary lymphoid tissue (TLT) can form within an inflamed organ, including the CNS. However, little is known about TLT formation in the neuroretina. In a novel spontaneous autoimmune mouse model of uveitis (R161H), we identified well-organized lymphoid aggregates in the retina and examined them for TLT characteristics. Presence of immune cells, tissue-specific markers, and gene expression patterns typically associated with germinal centers and T follicular helper cells were examined using immunohistochemistry and gene analysis of laser capture microdissected retina. Our data revealed the retinal lymphoid structures contained CD4(+) T cells and B cells in well-defined zonal areas that expressed classic germinal center markers, peanut lectin (agglutinin) and GL-7. Gene expression analysis showed upregulation of T follicular helper cell markers, most notably CXCR5 and its ligand CXCL13, and immunohistochemical analysis confirmed CXCR5 expression, typically associated with CD4(+) T follicular helper cells. Highly organized stromal cell networks, a hallmark of organized lymphoid tissue, were also present. Positive staining for phospho-Zap70 in retina-specific T cells indicated CD4(+) T cells were being activated within these lymphoid structures. CD138(+)/B220(+) plasma cells were detected, suggesting the retinal lymphoid aggregates give rise to functional germinal centers, which produce Abs. Interestingly, eyes with lymphoid aggregates exhibited lower inflammatory scores by fundus examination and a slower initial rate of loss of visual function by electroretinography, compared with eyes without these structures. Our findings suggest that the lymphoid aggregates in the retina of R161H mice represent organized TLT, which impact the course of chronic uveitis.

Characterization of a New Epitope of IRBP That Induces Moderate to Severe Uveoretinitis in Mice With H-2b Haplotype

PURPOSE

Experimental autoimmune uveitis (EAU) induced in mice using the retinal antigen interphotoreceptor retinoid binding protein (IRBP) is an animal model for posterior uveitis in humans. However, EAU induced by native IRBP protein or its widely used epitope amino acid residues 1 to 20 of human IRBP (hIRBP1-20) is inconsistent, often showing low scores and incidence. We found an urgent need to identify a better pathogenic epitope for the C57BL/6 strain.

METHODS

Mice were immunized with uveitogenic peptides or with native bovine IRBP. Clinical and histological disease and associated immunological responses were evaluated. Truncated and substituted peptides, as well as bioinformatic analyses, were used to identify critical major histocompatibility complex (MHC)/T cell receptor (TCR) contact residues and the minimal core epitope.

RESULTS

The new uveitogenic epitope of IRBP, amino acid residues 651 to 670 of human IRBP (LAQGAYRTAVDLESLASQLT [hIRBP651-670]) is uveitogenic for mice of the H-2b haplotype and elicits EAU with a higher severity and incidence in C57BL/6 mice than the previously characterized hIRBP1-20 epitope. Using truncated and substituted peptides, as well as bioinformatic analysis, we identified the critical contact residues with MHC/TCR and defined the minimal core epitope. This made it possible to design MHC tetramers and use them to detect epitope-specific T cells in the uveitic eye and in lymphoid organs of hIRBP651-670-immunized mice.

CONCLUSIONS

Data suggest that hIRBP651-670 is an epitope naturally processed from a conserved region of native IRBP, potentially explaining its relatively high uveitogenicity. This epitope should be useful for basic and preclinical studies of uveitis in the C57BL/6 model and gives access to genetically engineered mice available on this background.

Investigation of the relationship between the onset of arthritis and uveitis in genetically predisposed SKG mice

Introduction

Systemic rheumatic conditions are often accompanied by intraocular inflammatory disease (termed uveitis). Despite the frequent manifestation of uveitis with arthritis, very little is understood of the underlying mechanisms that mediate the eye’s susceptibility to disease. The genetically susceptible SKG mouse strain develops arthritis that arises from an inherent mutation that disrupts T-cell antigen receptor signal transduction and thymic selection. The ensuing T-cell–mediated disease is further modulated through exposure to microbial triggers. The purpose of this study was to elucidate how a genetically determined shift in the T-cell repertoire toward self-reactive T cells that drive arthritis influences uveitis in SKG mice.

Methods

SKG mice (BALB/c mice that harbor the W163C point mutation in zeta-chain-associated protein kinase 70 [i.e., ZAP-70]) were housed under arthritis-resistant, specific pathogen–free conditions. Arthritis was induced by intraperitoneal injection with fungal glucans (zymosan or curdlan). Arthritis onset and severity were evaluated by clinical scoring, histopathology and infrared imaging within the joints. Periocular traits involving blepharoconjunctivitis were evaluated by clinical scoring and histology. Eyes were evaluated for signs of anterior uveitis using intravital videomicroscopy to document cell-trafficking responses within the iris vasculature and stroma and by histology to detect inflammatory infiltrate and tissue damage within the anterior and posterior eye segments.

Results

Exposure to zymosan resulted in the predicted arthritic, sexually dimorphic phenotype in SKG mice. The eyes of SKG mice exhibited episodic intravascular cellular responses to zymosan or curdlan as indicated by significant increases in leukocyte–endothelium interactions akin to ocular vasculitis. However, despite the significant increase in early cell-trafficking responses, cellular infiltration into the iris stroma was not observed and histopathological signs indicative of a sustained uveitis were absent. Instead, eyes of SKG mice developed blepharoconjunctivitis that coincided with arthritis and exhibited sexual dimorphism.

Conclusions

This study underscores the complexity surrounding the pathogenesis of uveitis and its relationship with arthritis. The findings suggest that distinct mechanisms exist by which pathogenic autoimmune T cells target the eyes versus joints, which likely involves the environmental context but nonetheless should be taken into account in the identification and development of effective therapies for each organ.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0725-z) contains supplementary material, which is available to authorized users.

Application of Humanized Mice in Immunological Research

During the past decade, the development of humanized mouse models and their general applications in biomedical research greatly accelerated the translation of outcomes obtained from basic research into potential diagnostic and therapeutic strategies in clinic. In this chapter, we firstly present an overview on the history and current progress of diverse humanized mouse models and then focus on those equipped with reconstituted human immune system. The update advancement in the establishment of humanized immune system mice and their applications in the studies of the development of human immune system and the pathogenesis of multiple human immune-related diseases are intensively reviewed here, while the shortcoming and perspective of these potent tools are discussed as well. As a valuable bridge across the gap between bench work and clinical trial, progressive humanized mouse models will undoubtedly continue to play an indispensable role in the wide area of biomedical research.

Macrophages and Uveitis in Experimental Animal Models

Resident and infiltrated macrophages play relevant roles in uveitis as effectors of innate immunity and inductors of acquired immunity. They are major effectors of tissue damage in uveitis and are also considered to be potent antigen-presenting cells. In the last few years, experimental animal models of uveitis have enabled us to enhance our understanding of the leading role of macrophages in eye inflammation processes, including macrophage polarization in experimental autoimmune uveoretinitis and the major role of Toll-like receptor 4 in endotoxin-induced uveitis. This improved knowledge should guide advantageous iterative research to establish mechanisms and possible therapeutic targets for human uveitis resolution.

Immune mechanisms in inflammatory and degenerative eye disease

It has recently been recognized that pathology of age-associated degenerative eye diseases such as adult macular degeneration (AMD), glaucoma and diabetic retinopathy, have strong immunological underpinnings. Attempts have been made to extrapolate to age-related degenerative disease insights from inflammatory processes associated with non-infectious uveitis, but these have not yet been sufficiently informative. Here we review recent findings on the immune processes underlying uveitis and those that have been shown to contribute to AMD, discussing in this context parallels and differences between overt inflammation and para-inflammation in the eye. We propose that mechanisms associated with ocular immune privilege, in combination with paucity of age-related antigen(s) within the target tissue, dampen what could otherwise be overt inflammation and result in the para-inflammation that characterizes age-associated neurodegenerative disease.

Caffeic acid phenethyl ester lessens disease symptoms in an experimental autoimmune uveoretinitis mouse model

Experimental autoimmune uveoretinitis (EAU) is an autoimmune disease that models human uveitis. Caffeic acid phenethyl ester (CAPE), a phenolic compound isolated from propolis, possesses anti-inflammatory and immunomodulatory properties. CAPE demonstrates therapeutic potential in several animal disease models through its ability to inhibit NF-κB activity. To evaluate these therapeutic effects in EAU, we administered CAPE in a model of EAU that develops after immunization with interphotoreceptor retinal-binding protein (IRBP) in B10.RIII and C57BL/6 mice. Importantly, we found that CAPE lessened the severity of EAU symptoms in both mouse strains. Notably, treated mice exhibited a decrease in the ocular infiltration of immune cell populations into the retina; reduced TNF-α, IL-6, and IFN-γ serum levels: and inhibited TNF-α mRNA expression in retinal tissues. Although CAPE failed to inhibit IRBP-specific T cell proliferation, it was sufficient to suppress cytokine, chemokine, and IRBP-specific antibody production. In addition, retinal tissues isolated from CAPE-treated EAU mice revealed a decrease in NF-κB p65 and phospho-IκBα. The data identify CAPE as a potential therapeutic agent for autoimmune uveitis that acts by inhibiting cellular infiltration into the retina, reducing the levels of pro-inflammatory cytokines, chemokine, and IRBP-specific antibody and blocking NF-κB pathway activation.

Optical coherence tomography based microangiography for quantitative monitoring of structural and vascular changes in a rat model of acute uveitis in vivo: a preliminary study

Uveitis models in rodents are important in the investigation of pathogenesis in human uveitis and the development of appropriate therapeutic strategies for treatment. Quantitative monitoring of ocular inflammation in small animal models provides an objective metric to assess uveitis progression and/or therapeutic effects. We present a new application of optical coherence tomography (OCT) and OCT-based microangiography (OMAG) to a rat model of acute anterior uveitis induced by intravitreal injection of a killed mycobacterial extract. OCT/OMAG is used to provide noninvasive three-dimensional imaging of the anterior segment of the eyes prior to injection (baseline) and two days post-injection (peak inflammation) in rats with and without steroid treatments. OCT imaging identifies characteristic structural and vascular changes in the anterior segment of the inflamed animals when compared to baseline images. Characteristics of inflammation identified include anterior chamber cells, corneal edema, pupillary membranes, and iris vasodilation. In contrast, no significant difference from the control is observed for the steroid-treated eye. These findings are compared with the histology assessment of the same eyes. In addition, quantitative measurements of central corneal thickness and iris vessel diameter are determined. This pilot study demonstrates that OCT-based microangiography promises to be a useful tool for the assessment and management of uveitis in vivo.

Immunotherapeutic strategies in autoimmune uveitis

Autoimmune uveitis is an organ-specific disorder characterized by irreversible lesions to the eye that predominantly affect people in their most productive years and is among the leading causes of visual deficit and blindness. Currently available therapies are effective in the treatment of a wide spectrum of uveitis, but are often associated with severe side effects. Here, we review ongoing research with promising immunomodulatory therapeutic strategies, describing their specific features, interactions and the responses triggered by the targeted immune molecules that aim to minimize clinical complications and the likelihood of disease relapse. We first review the main features of the disease, diagnostic tools, and traditional forms of therapy, as well as the animal models predominantly used to understand the pathogenesis and test the novel intervention approaches aiming to control the acute immune and inflammatory responses and to dampen chronic responses. Both exploratory research and clinical trials have targeted either the blockade of effector pathways or of their companion co-stimulatory molecules. Examples of targets are T cell receptors (CD3), their co-stimulatory receptors (CD28, CTLA-4) and corresponding ligands (B7-1 and B7-2, also known as CD80 and CD86), and cytokines like IL-2 and their receptors. Here, we summarize the available evidence on effectiveness of these treatments in human and experimental uveitis and highlight a novel CD28 antagonist monovalent Fab′ antibody, FR104, which has shown preclinical efficacy suppressing effector T cells while enhancing regulatory T cell function and immune tolerance in a humanized graft-versus-host disease (GVHD) mice model and is currently being tested in a mouse autoimmune uveitis model with encouraging results.

Effective Arrestin-Specific Immunotherapy of Experimental Autoimmune Uveitis with RTL: A Prospect for Treatment of Human Uveitis

PURPOSE

To evaluate the immunotherapeutic efficacy of recombinant T cell receptor ligands (RTLs) specific for arrestin immunity in treatment of experimental autoimmune uveitis (EAU) in humanized leukocyte antigen (HLA-DR3) transgenic (Tg) mice.

METHODS

We generated de novo recombinant human DR3-derived RTLs bearing covalently tethered arrestin peptides 291-310 (RTL351) or 305-324 (RTL352). EAU was induced by immunization of HLA-DR3 mice with arrestin or arrestin peptide and treated with RTLs by subcutaneous delivery. T cell proliferation and cytokine expression was measured in RTL-treated and control mice.

RESULTS

RTL351 prevented the migration of cells outside of the spleen and the recruitment of inflammatory cells into the eye, and provided full protection against inflammation from EAU induced with arrestin or arrestin peptides. RTL351 significantly inhibited T cell proliferation and secretion of inflammatory cytokines interleukin 2 (IL-2), interferon γ (IFN-γ), IL-6, and IL-17 and chemokines (macrophage inflammatory proteins [MIP-1a] and regulated and normal T cell expressed and secreted [RANTES]), which is in agreement with the suppression of intraocular inflammation. RTL350 ("empty," no peptide) and RTL352 were not effective.

CONCLUSIONS

Immunotherapy with a single RTL351 successfully prevented and treated arrestin-induced EAU in HLA-DR3 mice and provided proof of concept for therapy of autoimmune uveitis in human patients. The beneficial effects of RTL351 should be attributed to a significant decrease in Th1/Th17 mediated inflammation.

TRANSLATIONAL RELEVANCE

Successful therapies for autoimmune uveitis must specifically inhibit pathogenic inflammation without inducing generalized immunosuppression. RTLs can offer such an option. The single retina-specific RTLs may have a value as potential immunotherapeutic drug for human autoimmune uveitis because they effectively prevent disease induced by multiple T cell specificities.

IL-27p28 inhibits central nervous system autoimmunity by concurrently antagonizing Th1 and Th17 responses

Central nervous system (CNS) autoimmunity such as uveitis and multiple sclerosis is accompanied by Th1 and Th17 responses. In their corresponding animal models, experimental autoimmune uveitis (EAU) and experimental autoimmune encephalomyelitis (EAE), both responses are induced and can drive disease independently. Because immune responses have inherent plasticity, therapeutic targeting of only one pathway could promote the other, without reducing pathology. IL-27p28 antagonizes gp130, required for signaling by IL-27 and IL-6, which respectively promote Th1 and Th17 responses. We therefore examined its ability to protect the CNS by concurrently targeting both effector responses. Overexpression of IL-27p28 in vivo ameliorated EAU as well as EAE pathology and reduced tissue infiltration by Th1 and Th17 cells in a disease prevention, as well as in a disease reversal protocol. Mechanistic studies revealed inhibition of Th1 and Th17 commitment in vitro and decreased lineage stability of pre-formed effectors in vivo, with reduction in expression of gp130-dependent transcription factors and cytokines. Importantly, IL-27p28 inhibited polarization of human T cells to the Th1 and Th17 effector pathways. The ability of IL-27p28 to inhibit generation as well as function of pathogenic Th1 and Th17 effector cells has therapeutic implications for controlling immunologically complex autoimmune diseases.

Uveitis in mouse and man

Uveitis is underappreciated as a sight-threatening cause of blindness. There are two broad causative classes of uveitis: infectious and non-infectious. Non-infectious uveitis is considered a prototypical autoimmune disorder based mainly on data from experimental models in the mouse. Several different experimental models exist that reflect the different types of uveitis in man (anterior, intermediate, and posterior uveitis). These models have demonstrated that uveitis is predominantly a Th1/Th17 mediated disease, although innate immune cells play a significant role both in induction of disease and in tissue damage. Most experimental models of uveitis rely on activation of the innate immune system by use of adjuvants that activate a range of pathogen recognition receptors (PRRs). This begs the question of the underlying role of initial and/or persistent infection, including latent infection, in immune-mediated uveitis in which active infection cannot be demonstrated. This further raises the possibility of pathogenic mechanisms such as antigenic cross-reactivity and molecular mimicry. Alternatively, residual/latent antigen from infectious agents may act as "endogenous" adjuvants for induction of immune reactions to damaged/altered self antigen, suggesting a commonality in pathogenesis for both infectious and non-infectious uveitis in man.

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.

Cell-based therapies for ocular inflammation

Since the plasticity and the potential for re-programming cells has become widely accepted, there has been great interest in cell-based therapies. These are being applied to a range of diseases, not least ocular diseases, where it is assumed that there is a reduced risk of immune rejection although this may be more perceived than real. There are two broad classes of cell-based therapies: those aimed at restoring structure and function of specific tissues and cells; and those directed towards restoring immunological homeostasis by controlling the damaging effects of inflammatory disease. Stem cells of all types represent the first group and prototypically have been used with the aim of regenerating failing cells. In contrast, immune cells have been suggested as potential modulators of inflammation. However, there is functional overlap in these two applications, with some types of stem cells, such as mesenchymal stem cells, demonstrating a potent immunomodulatory effect. This review summarises recent information on cell based therapies for ocular disease, with special emphasis on ocular inflammatory disease, and explores current uses, potential and limitations.

Gene therapy for noninfectious uveitis

Noninfectious intraocular inflammatory disease remains a significant cause of visual loss, even with current systemic immunosuppression. Alternative novel treatments are thus required, particularly for severe forms of posterior uveitis. Encouraging results from several phase I/II clinical trials of gene therapy for monogenic retinal disorders have paved the way for the development of this approach for other ocular conditions. Gene therapy for uveitis offers the possibility of potent, self-regulating, long-term disease control following a single treatment and without systemic side effects. To date, gene therapy approaches using interleukin-10, interleukin-1 receptor antagonist, interferon-alpha, soluble TNF-alpha receptors, and alpha-MSH gene transfer have been used successfully to attenuate experimental animal models of uveitis. This review evaluates these preclinical studies, considers the route to clinical application, and explores future targets and approaches.

Characterization of retinal expression of vascular cell adhesion molecule (VCAM-1) during experimental autoimmune uveitis

Leukocyte adhesion to the blood retinal barrier is a critical step in the pathogenesis of non-infectious uveitis and is mediated in part through the induction of adhesion molecules on retinal cells. Here, we have investigated the retinal expression of Vascular Cell Adhesion Molecule 1 (VCAM-1) in mouse experimental models of non-infectious uveitis. For each eyes, a histological score was given, and the expression of VCAM-1 analyzed by immunohistology. Co-labellings for GFAP, endoglin, aquaporin 4 and recoverin were also performed in order to determine which cell type expressed VCAM-1. In low grade uveitis, obtained after adoptive transfer of semi-purified autoreactive lymphocytes, VCAM-1 was only punctually expressed in the internal limiting membrane and epithelial cells of the ciliary body. Using the same adoptive transfer protocol, we found that, in correlation with disease severity, the staining extended to all internal limiting membranes, vasculitis lesions, Müller cell extensions, outer limiting membranes and RPE cells. VCAM-1 expression in the inner limiting membrane and Müller cell extensions co-stained with GFAP expression. In vasculitis lesions, VCAM-1 co-localized with either GFAP and endoglin expression. The labeling in the outer limiting membrane, did not exactly co-stained with AQ4 (Müller cells marker) or recoverin (photoreceptor marker) and the nature of this expression remained unexplained. Finally, VCAM-1 expression was also analyzed in classical experimental autoimmune uveitis eyes, and a similar pattern of expression was found. In conclusion VCAM-1 is expressed on all blood retinal barrier cells during experimental non-infectious uveitis and might thus play an important role in inflammatory cell recruitment during disease development.

Detection of an autoreactive T-cell population within the polyclonal repertoire that undergoes distinct autoimmune regulator (Aire)-mediated selection

The autoimmune regulator (Aire) plays a critical role in central tolerance by promoting the display of tissue-specific antigens in the thymus. To study the influence of Aire on thymic selection in a physiological setting, we used tetramer reagents to detect autoreactive T cells specific for the Aire-dependent tissue-specific antigen interphotoreceptor retinoid-binding protein (IRBP), in the polyclonal repertoire. Two class II tetramer reagents were designed to identify T cells specific for two different peptide epitopes of IRBP. Analyses of the polyclonal T-cell repertoire showed a high frequency of activated T cells specific for both IRBP tetramers in Aire(-/-) mice, but not in Aire(+/+) mice. Surprisingly, although one tetramer-binding T-cell population was efficiently deleted in the thymus in an Aire-dependent manner, the second tetramer-binding population was not deleted and could be detected in both the Aire(-/-) and Aire(+/+) T-cell repertoires. We found that Aire-dependent thymic deletion of IRBP-specific T cells relies on intercellular transfer of IRBP between thymic stroma and bone marrow-derived antigen-presenting cells. Furthermore, our data suggest that Aire-mediated deletion relies not only on thymic expression of IRBP, but also on proper antigen processing and presentation of IRBP by thymic antigen-presenting cells.

Mesenchymal stem cells induce functionally active T-regulatory lymphocytes in a paracrine fashion and ameliorate experimental autoimmune uveitis

PURPOSE

Mesenchymal stem/progenitor cells (MSCs) have regenerative and immunomodulatory properties, exerted by cell-cell contact and in a paracrine fashion. Part of their immunosuppressive activity has been ascribed to their ability to promote the induction of CD4+CD25+FoxP3+ T lymphocytes with regulatory functions (Treg). Here the authors studied the effect of MSCs on the induction of Treg and on the development of autoimmunity, and they examined the possibility that MSC-mediated Treg induction could be attributed to the secretion of soluble factors.

METHODS

The authors induced experimental autoimmune uveitis (EAU) in mice by immunization with the 1-20 peptide of the intraphotoreceptor binding protein. At the same time, some of the animals were treated intraperitoneally with syngeneic MSCs. The authors checked T-cell responses and in vitro Treg conversion by cell proliferation and blocking assays, in cell-cell contact and transwell settings. TGFβ and TGFβ receptor gene expression analyses were performed by real-time PCR.

RESULTS

The authors found that a single intraperitoneal injection of MSCs was able to significantly attenuate EAU and that a significantly higher percentage of adaptive Treg was present in MSC-treated mice than in MSC-untreated animals. In vitro blocking of antigen presentation by major histocompatibility complex class II precluded priming and clonal expansion of antigen-specific Treg, whereas blockade of TGFβ impaired the expression of FoxP3, preventing the conversion of CD4+ T cells into functionally active Treg.

CONCLUSIONS

The authors demonstrated that MSCs can inhibit EAU and that their immunomodulatory function is due at least in part to the induction of antigen-specific Treg in a paracrine fashion by secreting TGFβ.

Cutting-edge issues in autoimmune uveitis

Autoimmune uveitis (AIU) is among the leading causes of preventable blindness. It can be isolated, precede, or appear in the course of a systemic autoimmune inflammatory disease. When suspected, AIU should be promptly referred to an ophthalmologist for proper anatomic classification and local treatment. In recurrent and chronic forms, systemic treatment should be started, usually with corticosteroids and immunesuppressors. In cases of lack of efficacy or intolerance, biologic agents such as monoclonal antibodies anti-TNF (infliximab and adalimumab) and others (abatacept and tocilizumab) are being used. The clinical diseases associated to AIU and the experimental models have helped in the understanding of the pathogenic mechanism. The treatment schemes have improved, and recent advances in basic knowledge are leading to even more effective targeted therapies.

Rodent models of experimental autoimmune uveitis

The model of experimental autoimmune uveitis (EAU) in mice and in rats is described. EAU targets immunologically privileged retinal antigens and serves as a model of autoimmune uveitis in humans as well as a model for autoimmunity in a more general sense. EAU is a well-characterized, robust, and reproducible model that is easily followed and quantitated. It is inducible with synthetic peptides derived from retinal autoantigens in commonly available strains of rats and mice. The ability to induce EAU in various gene-manipulated, including HLA-transgenic, mouse strains makes the EAU model suitable for the study of basic mechanisms as well as in clinically relevant interventions.

Protective effect of pristane on experimental autoimmune uveitis

This study evaluates the effects of pristane and phytol, two mineral oils with pro-oxidative effects, on the course of experimental autoimmune uveitis. C57BL6 mice were immunized with IRBP1-20 peptide emulsified in CFA and treated five days prior to immunization with phytol or with pristane or with PBS as control. Administration of pristane reduces the incidence and severity of IRBP-induced uveitis as demonstrated by the decrease in vasculitis and inflammatory foci in fundus and by a reduction in histological damages and leukocyte infiltration compared to untreated or phytol-treated mice. The protective effect observed is associated with a decreased activation of peripheral CD4+ and CD8+ T lymphocytes and a decrease in the intensity of the Th1 and Th17 autoimmune response to IRBP in pristane-treated mice compared to control mice, as evidenced by the decreased production of IFNγ and IL17 by IRBP-specific lymphocytes from lymph nodes draining the site of immunization and by the increased production of anti-IRBP IgG1 over IgG2a. In addition, HUVEC and ARPE-19 cells incubated with the sera of mice treated with pristane presented a reduced production of H(2)O(2). The benefit of lowering the systemic oxidative stress by pristane in the course of EAU was confirmed by injecting the antioxidant NAC in IRBP-immunized mice. As pristane, NAC decreased clinical and histological inflammation of the retina and preserved the integrity of the hemato-retinal barrier. Finally, the protective effect of pristane on the development of EAU suggests that some mineral oils may represent a new therapeutic strategy in human uveitis.

WITHDRAWN: A brief autobiography

The Publisher regrets that this article is an accidental duplication of an article that has already been published, doi:10.1016/j.jaut.2011.05.017 The duplicate article has therefore been withdrawn.

Uveitis-associated epitopes of retinal antigens are pathogenic in the humanized mouse model of uveitis and identify autoaggressive T cells

Noninfectious uveitis is a leading cause of blindness and thought to involve autoimmune T cell responses to retinal proteins (e.g., retinal arrestin [soluble-Ag (S-Ag)]). There are no known biomarkers for the disease. Susceptibility is associated with HLA, but little is known about susceptible class II alleles or the potentially pathogenic epitopes that they present. Using a humanized HLA-transgenic mouse model of S-Ag-induced autoimmune uveitis, we identified several susceptible and resistant alleles of HLA-DR and -DQ genes and defined pathogenic epitopes of S-Ag presented by the susceptible alleles. The sequences of these epitopes overlap with some previously identified peptides of S-Ag ("M" and "N"), known to elicit memory responses in lymphocytes of uveitis patients. HLA-DR-restricted, S-Ag-specific CD4(+) T cells could be detected in blood and draining lymph nodes of uveitic mice with HLA class II tetramers and transferred the disease to healthy mice. Importantly, tetramer-positive cells were detected in peripheral blood of a uveitis patient. To our knowledge, these findings provide the first tangible evidence that an autoimmune response to retina is causally involved in pathogenesis of human uveitis, demonstrating the feasibility of identifying and isolating retinal Ag-specific T cells from uveitis patients and may facilitate their development as biomarkers for the disease.

Chella David: a lifetime contribution in translational immunology

Immunology, like most scientific disciplines, is filled with buzz words. One such buzz word or term has been coined "translational immunology". Indeed, translational research is amongst the most popular expressions used to justify the use of basic research in the hopes that such research will lead to solutions to clinical problems. In fact, no such justification is needed and some of the most important observations in clinical medicine have been derived from basic science; basic science that had no idea at its time of its usefulness in clinical medicine. This special issue is devoted to Chella David. Chella's contributions in immunology have been legion. Before inbred mice became popular, long before multi-million dollar companies were developed to develop such models, Chella David was hard at the bench studying the genetics of the murine immune system and the importance of such mouse models in autoimmune diseases. Importantly, Dr. David provided animals without strings, without the burdens of MTAs, that now impede research. Chella has been generous with his time, with his reagents, and has been a caring and devoted mentor to generations of students. This issue is part of our series to recognize autoimmunologists and dedicated themes that include papers in multiple disciplines of immunology, but especially are focused on cutting-edge applications that will improve clinical therapeutics. Chella David, at age 75, is an athlete in immunology and still keeps going with the same enthusiasm as manifest as a young post-doc.

Genetics in ocular inflammation--basic principles

The ability to identify individuals at risk of ocular disease, or to determine the potential severity of disease or response to therapy is the current focus of much research. These studies are being led by genetic analysis of individuals to determine associations with alterations in gens that may explain manifestations of particular diseases. In this review we consider the basic principles behind genetic studies in general and of ocular disease in particular. We address the methodologies being utilised, and the results derived so far. The potential and pitfalls of such studies are relevant to the concept of personalised medicine and better defined clinical trials.

An eye for discovery

Vision research has often led to significant advances in our understanding of biology. There has also been particular success in translating basic research in the eye into breakthrough clinical therapies that mark important milestones for ophthalmology and also for medical research. Anti-VEGF therapy for age-related macular degeneration was named as one of the top ten science advancements of the year 2006. Only two years later, successful transfer of the RPE65 gene into retinal pigment epithelium of patients with Leber congenital amaurosis was noted as one of the most important clinical applications of gene therapy. The articles in this Review series outline current developments in vision research and highlight its continued importance in ophthalmology and medicine.

A look at autoimmunity and inflammation in the eye

Autoimmune and inflammatory uveitis are a group of potentially blinding intraocular inflammatory diseases that arise without a known infectious trigger and are often associated with immunological responses to unique retinal proteins. In the United States, about 10% of the cases of severe visual handicap are attributed to this group of disorders. As I discuss here, experimental models of ocular autoimmunity targeting retinal proteins have brought about a better understanding of the basic immunological mechanisms involved in the pathogenesis of uveitis and are serving as templates for the development of novel therapies.

Differential responses to Smith D autoantigen by mice with HLA-DR and HLA-DQ transgenes: dominant responses by HLA-DR3 transgenic mice with diversification of autoantibodies to small nuclear ribonucleoprotein, double-stranded DNA, and nuclear antigens

Anti-Smith (Sm) D autoantibodies are specific for systemic lupus erythematosus. In this investigation, the influence of HLA-D genes on immune responses to SmD was investigated. Mice with HLA-DR3, HLA-DR4, HLA-DQ0601, HLA-DQ0604, or HLA-DQ8 transgenes were immunized with recombinant SmD1, and their Ab responses were analyzed. Analysis by ELISA showed that all strains responded well to SmD. However, when synthetic SmD peptides were used as substrate, DR3 mice had the highest Ab response followed by DQ8, DQ0604, DQ0601, and DR4. A similar trend was observed in Western blot analysis using WEHI 7.1 cell lysate as the substrate, with the exception that DR4 mice did not generate detectable amounts of Abs. Only sera from DR3 and DQ0604 mice immunoprecipitated A-ribonucleoprotein (RNP), SmB, and SmD. Intermolecular epitope spreading to A-RNP and SmB was evident in DR3 and DQ0604 mice, as sera depleted of anti-SmD Abs were reactive with these proteins. DR3 mice also generated an immune response to C-RNP. Anti-nuclear Abs were detected in the majority of the DR3 mice, whereas moderate reactivities were seen in DQ0604 and DQ8 mice. Interestingly, only DR3 mice mounted an anti-dsDNA Ab response. Approximately half of the anti-dsDNA Abs were cross-reactive with SmD. Ab responses correlated with the strength of the T cell responses. Thus, HLA-DR3 appears to be the dominant HLA-D gene that determines the magnitude and quality of the anti-SmD immune response. In addition, our findings provide insights into the origin of the anti-dsDNA Abs often detected in patients with systemic lupus erythematosus.