Antigen therapy of experimental autoimmune encephalomyelitis selectively induces apoptosis of pathogenic T cells

Administration of high-dose myelin antigen induces massive T cell apoptosis in experimental autoimmune encephalomyelitis (EAE) but the nature of the target cells remains elusive. Here we have used a cell line established in eGFP-transgenic Lewis rats to distinguish between pathogenic and bystander T cells in adoptive transfer EAE. Intravenous application of gpMBP strongly reduced the amount of encephalitogenic cells in spinal cord and spleen while the number of the other T cells remained constant. This could be attributed to their differential sensitivity to apoptosis. Thus, antigen therapy selectively targets pathogenic T cells and should therefore limit potential adverse effects.     

Characterization of T cells that are activated after depletion of major encephalitogenic T cells in rat autoimmune encephalomyelitis

In rat experimental autoimmune encephalomyelitis (EAE), encephalitogenic T cells mainly use Vbeta8.2 of TCR, but it is not clear whether Vbeta8.2 is the sole encephalitogenic TCR. To address this issue, we examined the immunological status of Lewis rats that had been treated with anti-Vbeta8.2 mAb and immunized with myelin basic protein (MBP). It was demonstrated that rats in which the majority of Vbeta8.2+ T cells had been depleted developed clinical EAE and possessed newly expanded Vbeta10. Analysis of T cell lines established from these animals revealed that T line cells responded to a minor epitope in the MBP molecule. However, treatment with a mixture of anti-Vbeta8.2 and anti-Vbeta10 mAbs reduced the clinical severity of EAE but did not induce complete suppression of the disease due to new activation of Vbeta6. These findings suggest that rapid and frequent examination of the TCR repertoire is essential to identify pathogenic TCRs and to establish TCR-based immunotherapy for autoimmune diseases.     

Long-term persistence of clonally expanded T cells in patients with polymyositis

Polymyositis is a CD8(+) T-cell-mediated disease. T-cell clonal expansions are observed at disease onset, but little is known about their persistence over time. Qualitative and quantitative spectratyping demonstrated that PM relapse features dramatically perturbed blood T-cell repertoires but is not associated with the emergence of new T-cell clones. It is striking that patients in remission also maintained all their T-cell repertoire abnormalities. The clonally expanded T-cells displayed a memory phenotype, expressed intracellular perforin, and dramatically responded to IL-2, showing a potential to be reactivated upon appropriate conditions. These results indicate that persistent T-cell clonal expansion is an important feature of polymyositis.     

Characterization of T cell receptor (TCR) of organ-specific autoimmune disease-inducing T cells and TCR-based immunotherapy with DNA vaccines

Organ-specific autoimmune diseases and their animal models are characterized by the finding that the development of the diseases is closely associated with, or induced by, T cells reactive to organ-specific antigens. Therefore, the identification of T cell receptors (TCR) used by disease-inducing T cells within a short period of time is a key factor for designing TCR-based immunotherapy. The findings introduced in this article show that TCR associated with the development of multiple sclerosis and experimental autoimmune diseases including encephalomyelitis (EAE), neuritis (EAN) and carditis (EAC) are identifiable by complementarity-determining region 3 (CDR3) spectratyping analysis and subsequent sequencing of the CDR3 region of spectratype-derived TCR clones. It is also demonstrated that immunotherapy targeting disease-associated TCR using monoclonal antibodies and DNA vaccines significantly reduced the histological severity, and completely suppressed the inflammation in some animals. Since depletion or suppression of one of several types of effector cells does not significantly improve the severity of the disease, combined TCR-based immunotherapy should be considered as a primary therapy for T cell-mediated autoimmune diseases. TCR-based immunotherapy after rapid identification of autoimmune disease-associated TCR by CDR3 spectratyping can be applicable, not only to animal, but also to human autoimmune diseases whose pathomechanism is poorly understood.     

B and T cells in the brains of autoimmune mice

Systemic lupus erythematosus (SLE) is an autoimmune disorder that can involve the central nervous system (CNS). Recently, we reported the presence of autoantibodies bound to the brain tissue of murine models of lupus; MRL/lpr and BXSB. We postulated that the source of these autoantibodies was in part due to in situ production, caused by the entry of B and T cells. Frozen brain sections of MRL/lpr and BXSB at 1 and 4 months of age were stained for CD3 (T cells) and CD19 (B cells) markers using an immunofluorescent antibody binding assay. Confocal fluorescence microscopy showed both CD3(+) and CD19(+) cells at 4 months of age only in MRL/lpr mice. There were no lymphocytes seen in the other autoimmune model, BXSB. Results suggest a difference in the mechanisms by which autoantibodies access the brain in these two autoimmune models of lupus.     

肌炎特异性自身抗体在多发性肌炎/皮肌炎及其他神经肌肉疾病的表达

目的 探讨肌炎特异性自身抗体(MSAs)在多发性肌炎/皮肌炎(PM/DM)及其他神经肌肉疾病的敏感度和特异度.方法 采用免疫斑点分析法测定63例PM/DM(PM/DM组)及60例神经肌肉疾病(非肌炎)患者(对照组)的血清抗Jo-1抗体和抗SRP抗体水平,分析其对PM/DM诊断的敏感度和特异度.结果 PM/DM组抗Jo-1和抗SRP抗体阳性率分别为17%和5%,对照组均为阴性.两种抗体诊断PM/DM特异度均为100%(95%CI:94%～100%),总敏感度为22%(95%CI:13%～34%).结论 抗Jo-1和抗SRP自身抗体对PM和DM特异度高.     

Diagnostic and pathogenic significance of glutamate receptor autoantibodies

Autoantibodies against glutamate receptors, first reported in Rasmussen encephalitis, have been observed in other focal epilepsies, central nervous system ischemic infarcts, transient ischemic attacks, sporadic olivopontocerebellar atrophy, systemic lupus erythematosus, and paraneoplastic encephalopathies. The detection of glutamate receptor autoantibodies is not useful in the evaluation of Rasmussen encephalitis but may be a biomarker for brain ischemia, and it is helpful in diagnosing certain paraneoplastic encephalopathies. Passive transfer of glutamate receptor autoantibodies from patients with systemic lupus erythematosus or paraneoplastic encephalopathy suggests that glutamate receptor autoantibodies can actively contribute to neurologic dysfunction.     

Mesenchymal stem cells effectively modulate pathogenic immune response in experimental autoimmune encephalomyelitis

OBJECTIVE: To evaluate the ability of mesenchymal stem cells (MSCs), a subset of adult stem cells from bone marrow, to cure experimental autoimmune encephalomyelitis. METHODS: The outcome of the injection of MSCs, in mice immunized with the peptide 139-151 of the proteolipid protein (PLP), was studied analyzing clinical and histological scores of treated mice. The fate of MSCs labeled with the green fluorescent protein was tracked in vivo by a photon emission imaging system and postmortem by immunofluorescence. The modulation of the immune response against PLP was studied through the analysis of in vivo T- and B-cell responses and by the adoptive transfer of MSC-treated encephalitogenic cells. RESULTS: MSC-treated mice showed a significantly milder disease and fewer relapses compared with control mice, with decreased number of inflammatory infiltrates, reduced demyelination, and axonal loss. In contrast, no evidence of green fluorescent protein-labeled neural cells was detected inside the brain parenchyma, thus not supporting the hypothesis of MSCs transdifferentiation. In vivo, PLP-specific T-cell response and antibody titers were significantly lower in MSC-treated mice. When adoptively transferred, encephalitogenic T cells activated against PLP(139-151) in the presence of MSCs induced a milder disease compared with that induced by untreated encephalitogenic T cells. These cells showed decreased production of interferon-gamma and tumor necrosis factor-alpha and did not proliferate on antigen recall, and thus were considered anergic. INTERPRETATION: Overall, these findings suggest that the beneficial effect of MSCs in experimental autoimmune encephalomyelitis is mainly the result of an interference with the pathogenic autoimmune response.     

Anti-cytokine autoantibodies in experimental autoimmune neuritis in Lewis rats

Experimental autoimmune neuritis (EAN) is a CD4+ T-cell-mediated, inflammatory demyelinating disease of the peripheral nervous system (PNS) that serves as a model for Guillain-Barre syndrome (GBS) in humans. Cytokine production has been suggested to act a pathogenic role for EAN. To study the potential role of cytokines in context with cytokine autoantibodies (Aabs) in EAN, we used in situ hybridization to detect mRNA expression of interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, IL-4, IL-10, and transforming growth factor (TGF)-beta in lymph node mononuclear cell (MNC) and in sciatic nerve sections, as well as ELISA for detection of their autoantibodies in sera and cerebrospinal fluid (CSF) over the course of EAN. Increased mRNA expression for IFN-gamma and TNF-alpha was registered correlating with the peak of clinical signs of EAN, and high levels of mRNA expression for IL-4, IL-10, and TGF-beta were associated with EAN recovery. The levels of cytokine mRNAs were generally inversely correlated to their autoantibodies in serum and CSF, whereby the CSF levels were equal to or lower than the serum levels. Autoantibodies to IFN-gamma dose-dependently inhibited IFN-gamma-induced MHC expression by peritoneal macrophages proving a neutralizing biological effect of these autoantibodies. Our data demonstrate the existence of the anti-cytokine autoantibodies in the sera and CSF of rats with EAN; however, the role of anti-cytokine autoantibodies in the disease process of EAN remains to be resolved.     

The dynamics of effector T cells and Foxp3+ regulatory T cells in the promotion and regulation of autoimmune encephalomyelitis

The Th1/Th2 paradigm of T helper cell subsets had to be revised when IL-17 producing T cells (Th17) were identified as a distinct T helper cell lineage. Th17 cells are very efficient inducers of tissue inflammation and crucial initiators of organ-specific autoimmunity. Whereas Th17 cells promote autoimmune tissue inflammation, Foxp3+ regulatory T cells (T-reg) are necessary and sufficient to prevent autoimmunity throughout the life span of an individual. Here, we review recent findings of how responses of effector T cells and T-reg cells with a defined antigen-specificity develop in autoimmune encephalomyelitis. Moreover, Th17 cells and Foxp3+ T-reg seem to be dichotomously related in that TGF-beta induces Foxp3 in na?ve T cells, but TGF-beta and IL-6 together drive the generation of Th17 cells. Thus, we give an overview of how Th17 cells, induced Foxp3+ T-reg, as well as how naturally occurring T-reg cells might cooperate to promote and regulate autoimmune inflammation of the central nervous system (CNS). The monitoring of the population dynamics of these T cell subsets in reporter mice in vivo will enable us to revisit the pathogenic concept of autoimmune inflammation in the CNS and design rational and phase-specific therapeutic interventions.     

Myeloid dendritic cells in inclusion-body myositis and polymyositis

Dendritic cells (DCs), immune system cells central to the development of immunity, have not previously been reported in muscle in inclusion-body myositis (IBM). We performed immunohistochemical studies on muscle biopsy specimens from 50 patients using monoclonal antibodies that distinguish two classes of DCs, myeloid DC and plasmacytoid DC. In 17 of 20 IBM and 9 of 10 polymyositis (PM) specimens, myeloid DCs were present in substantial numbers, frequently surrounded and sometimes invading otherwise intact myofibers, and were part of dense collections of cells that included T cells. Dermatomyositis muscle had more plasmacytoid DCs than myeloid DCs, whereas IBM and PM had greater numbers of myeloid DCs. The stellate morphology of myeloid DCs in dense collections of cells that included T cells suggests local intramuscular antigen presentation in IBM and PM.     

Characterization of antineurofilament autoantibodies in Creutzfeldt-Jakob disease

The antineurofilament antibodies found in the serum of a chimpanzee with experimental Creutzfeldt-Jakob disease reacted specifically with the 200,000-dalton polypeptide of the purified neurofilament triplet. They also reacted strongly with thoroughly characterized neurofilament swellings of proximal axons of spinal cord motoneurons from beta,beta' iminodipropionitrile (IDPN)-intoxicated rats.     

神经元自身抗体及其不同检测方法在自身免疫性脑炎中的价值研究进展

神经元自身抗体是自身免疫性脑炎诊断的关键,免疫组织化学法/间接免疫荧光法、啮齿类动物离体海马神经元的免疫细胞化学法、免疫印迹法等是目前常用的抗体检测方法,血清及脑脊液样本在不同亚型的自身免疫性脑炎中抗体检测的敏感性不同.神经元自身抗体滴度与肿瘤的发生相关,但与预后的相关性仍存在争议.近年来关于常见自身免疫性脑炎亚型相关...     

Genetic control of pathogenic mechanisms in autoimmune demyelinating disease

Multiple sclerosis is a disease of discrete phenotypes in different individuals. Animal models have been useful in identifying self-antigens that become the focus of autoimmune attack and genetic loci that control susceptibility to disease. We have previously demonstrated a role for Fas-dependent pathogenesis in the induction of EAE in B10.PL mice immunized with MBP. Others have indicated a Fas-independent mechanism predominates in SJL mice immunized with PLP. Here we compare the response of (B10.PLxSJL)F1 and parental mice under similar conditions for induction of EAE. The results indicate that immunodominance and dominant pathogenic mechanisms are both under genetic control, but can be inherited independently. The data also indicate that the dominant pathogenic mechanism can change during the course of disease in an individual. Elucidation of the genetic elements controlling pathogenesis during the course of disease would provide important information in designing therapeutic strategies for individuals in a heterogeneous patient population.     

Characterization of ganglionic acetylcholine receptor autoantibodies

In myasthenia gravis (MG), autoantibodies bind to the alpha1 subunit and other subunits of the muscle nicotinic acetylcholine receptor (AChR). Autoimmune autonomic ganglionopathy (AAG) is an antibody-mediated neurological disorder caused by antibodies against neuronal AChRs in autonomic ganglia. Subunits of muscle and neuronal AChR are homologous. We examined the specificity of AChR antibodies in patients with MG and AAG. Ganglionic AChR autoantibodies found in AAG patients are specific for AChRs containing the alpha3 subunit. Muscle and ganglionic AChR antibody specificities are distinct. Antibody crossreactivity between AChRs with different alpha subunits is uncommon but can occur.     

C-protein in the skeletal muscle induces severe autoimmune polymyositis in Lewis rats.

To obtain a good animal model for polymyositis, we previously induced experimental autoimmune myositis (EAM) in Lewis rats by immunization with partially purified skeletal myosin. However, the nature of EAM-inducing antigen(s) in the partially purified myosin preparation remains unclear because it may contain several myositogenic antigens. In the present study, we further purified myosin and C-protein from partially purified myosin preparations and examined their EAM-inducing ability. It was revealed that immunization with both C-protein and purified myosin elicited EAM, which was essentially the same as that induced by partially purified myosin. However, their myositogenic ability was quite different. C-protein induced severe EAM of high histological grade and lesion frequency, whereas purified myosin induced only mild EAM. Immunohistochemical staining of C-protein-induced lesions demonstrated that muscle fiber-infiltrating cells were CD8beta+ T cells and macrophages and that CD4+ cells were mainly located in the endomysium and interfiber connective tissue. Collectively, these findings suggest that C-protein in the skeletal muscle is the major myositogenic antigen and induces inflammatory lesions mimicking those of human polymyositis.     

调节性T细胞在实验性变态反应性脑脊髓炎和多发性硬化发病中的作用

调节性T细胞(regulatory T cells,Treg)是一类具有免疫调节功能的T细胞哑群.近年来,Treg细胞在实验性变态反应性脑脊髓炎(experimental allergical encephalomyelitis,EAE)、多发性硬化(multiple sclerosis,MS)发病中的作用越来越受到关注,小鼠Treg细胞缺失可导致特异性自身免疫性疾病,增加Treg细胞的功能可以减轻或抑制EAE.最近的研究结果表明,MS本身也伴随着成熟Treg细胞的受损或功能障碍.     

The neurotransmitter glutamate and human T cells: glutamate receptors and glutamate-induced direct and potent effects on normal human T cells,cancerous human leukemia and lymphoma T cells,and autoimmune human T cells

Glutamate is the most important excitatory neurotransmitter of the nervous system, critically needed for the brain’s development and function. Glutamate has also a signaling role in peripheral organs. Herein, we discuss glutamate receptors (GluRs) and glutamate-induced direct effects on human T cells. T cells are the most important cells of the adaptive immune system, crucially needed for eradication of all infectious organisms and cancer. Normal, cancer and autoimmune human T cells express functional ionotropic and metabotropic GluRs. Different GluR subtypes are expressed in different T cell subtypes, and in resting vs. activated T cells. Glutamate by itself, at low physiological 10^?8M to 10^?5M concentrations and via its several types of GluRs, activates many key T cell functions in normal human T cells, among them adhesion, migration, proliferation, intracellular Ca²⁺ fluxes, outward K⁺ currents and more. Glutamate also protects activated T cells from antigen-induced apoptotic cell death. By doing all that, glutamate can improve substantially the function and survival of resting and activated human T cells. Yet, glutamate’s direct effects on T cells depend dramatically on its concentration and might be inhibitory at excess pathological 10^?3M glutamate concentrations. The effects of glutamate on T cells also depend on the specific GluRs types expressed on the target T cells, the T cell’s type and subtype, the T cell’s resting or activated state, and the presence or absence of other simultaneous stimuli besides glutamate. Glutamate also seems to play an active role in T cell diseases. For example, glutamate at several concentrations induces or enhances significantly very important functions of human T-leukemia and T-lymphoma cells, among them adhesion to the extracellular matrix, migration, in vivo engraftment into solid organs, and the production and secretion of the cancer-associated matrix metalloproteinase MMP-9 and its inducer CD147. Glutamate induces all these effects via activation of GluRs highly expressed in human T-leukemia and T-lymphoma cells. Glutamate also affects T cell-mediated autoimmune diseases. With regards to multiple sclerosis (MS), GluR3 is highly expressed in T cells of MS patients, and upregulated significantly during relapse and when there is neurological evidence of disease activity. Moreover, glutamate or AMPA (10^?8M to 10^?5M) enhances the proliferation of autoreactive T cells of MS patients in response to myelin proteins. Thus, glutamate may play an active role in MS. Glutamate and its receptors also seem to be involved in autoimmune rheumatoid arthritis and systemic lupus erythematosus. Finally, T cells can produce and release glutamate that in turn affects other cells, and during the contact between T cells and dendritic cells, the latter cells release glutamate that has potent effects on the T cells. Together, these evidences show that glutamate has very potent effects on normal, and also on cancer and autoimmune pathological T cells. Moreover, these evidences suggest that glutamate and glutamate-receptor agonists might be used for inducing and boosting beneficial T cell functions, for example, T cell activity against cancer and infectious organisms, and that glutamate-receptor antagonists might be used for preventing glutamate-induced activating effects on detrimental autoimmune and cancerous T cells.