T cells, cytokines, and autoantigens in multiple sclerosis

Specific antibodies to EBNA1 epitopes as risk factors for multiple sclerosis, a systematic review

Seroprevalence of anti-EBV antibodies was found to be almost 100% and 90% for multiple sclerosis patients and normal people, respectively. Furthermore, anti EBNA1 antibody which is an indicator of past EBV infection has a higher titer in the serum of Persons with MS (pwMS) compared to the EBV-infected subjects without MS. Though, this difference in anti-EBNA1 antibody titer between pwMS and non-MS controls is not a reliable marker to be used for discriminating pwMS and non-MS individuals. Some Studies have revealed specific epitopes on EBNA1 as the target for anti-EBNA1 antibodies in pwMS. Measuring antibody response against such specific epitopes can help better discriminate pwMS and non-MS individuals. This systematic review aims to obtain conclusive data from the studies which have sought to identify and map such epitopes on EBNA1. Five databases, including PubMed, Google Scholar, web of Science, Scopus, and Elsevier were searched for this purpose. Overall, 12 articles were finally included. Despite different articles describing not exactly the same epitopes, most of the epitopes described are within the amino acid sequence 385-420 of EBNA1. Among these epitopes, most of the epitopes have overlapping amino acid sequences with one another. The most highly overlapping sequence is RRPFF, which encompasses the amino acid 402 to 406 of EBNA1.

Multiple sclerosis and immune system biomarkers: Novel comparison in glatiramer acetate and interferon beta-1a-treated patient groups

BACKGROUND

Multiple sclerosis (MS) is a chronic, demyelinating disease of the central nervous system (CNS). T cells and B lymphocytes are involved in the development of this disease.

METHODS

The following biomarkers were determined in peripheral blood in 28 patients treated with glatiramer acetate (GA) and 21 patients treated with interferon beta 1-a (IFN): IL-10, BAFF, Mx1, IgG, IgG1, IgG2, IgG3 and IgG4 (at baseline and after 6 months of treatment). All participants had confirmed MS diagnosis.

OBJECTIVES

The primary objective is to assess a percentual change of biomarkers after 6 months since the first-line treatment initiation with GA or IFN. The secondary objective is to explore correlations between the baseline biomarkers' values (levels).

RESULTS

A positive trend was observed in the increase in IL-10 concentration by 30.33 % (IFN) and by 15.65 % (GA). In the IFN group, we observed a statistically significant increase in the BAFF protein concentration by 29.9% (P < 0.001). We found that Mx1 protein levels did not change with the administration of GA, which can be explained by the different mechanisms of action of GA. The serum levels of IgG immunoglobulins and both IgG1 and IgG4 subclasses in both groups of patients were increased. Thus, our data were in accordance with the generally accepted assumption that both IFN and GA are capable of modulating the B cell system.

CONCLUSIONS

Our results suggest that treatment with IFN and GA has a more pronounced influence on the B cell system of MS.

Lactobacillus acidipiscis Induced Regulatory Gamma Delta T Cells and Attenuated Experimental Autoimmune Encephalomyelitis

Multiple sclerosis is a chronic autoimmune disease involving the central nervous system, and shows a high disability rate. Its pathogenesis is complicated, and there is no good treatment. In recent years, with in-depth studies on the regulation of gastrointestinal flora, the relationship between the mammalian immune system and the intestinal flora has been extensively explored. Changes in the composition and structure of the gastrointestinal flora can affect the characteristics and development of the host immune system and even induce a series of central nervous system inflammation events. The occurrence and development of multiple sclerosis are closely related to the continuous destruction of the intestinal barrier caused by intestinal dysbacteriosis. In this study, we analyzed Lactobacillus acidipiscis in a mouse model of experimental autoimmune encephalomyelitis (EAE). We found that the amount of L. acidipiscis in the intestinal tract was inversely proportional to the progress of EAE development. In addition, the number of CD4+ FOXP3+ regulatory T cells in the mesenteric lymph nodes of mice increased significantly after the mice were fed with L. acidipiscis, and the differentiation of CD4+ T cells to Th1 and Th17 cells was inhibited. However, the protective effect of L. acidipiscis was lost in γδ T cell-deficient mice and hence was concluded to depend on the presence of regulatory γδ T cells in the intestinal epithelium. Moreover, including L. acidipiscis enhanced the development of Vγ1+γδ T cells but suppressed that of Vγ4+γδ T cells. In summary, our results demonstrated the ability of L. acidipiscis to induce generation of regulatory γδ T cells that suppress the development of the encephalomyelitic Th1 and Th17 cells and the progress of EAE.

Serum ADMA levels were positively correlated with EDSS scores in patients with multiple sclerosis

Multiple sclerosis (MS) is an autoinflammatory, chronic central nervous system disease. In the pathogenesis of the disease increased nitric oxide (NO) levels play an important role. Nitric oxide (NO) has neuroprotective effects in physiological conditions, however, it is thought that excessive NO formation in MS may lead to demyelination and axonal damage. Derivatives of methylarginine including asymmetric dimethyl arginine (ADMA), L-N monomethyl arginine (L-NMMA), symmetric dimethyl arginine (SDMA) directly or indirectly reduce NO production. Our aim was to measure the levels of methylarginine derivatives and citrulline, ornithine, arginine, homoarginine levels, which are metabolites associated with NO metabolism, in MS subgroups.

Screening Immunomodulators To Skew the Antigen-Specific Autoimmune Response

Current therapies to treat autoimmune diseases often result in side effects such as nonspecific immunosuppression. Therapies that can induce antigen-specific immune tolerance provide an opportunity to reverse autoimmunity and mitigate the risks associated with global immunosuppression. In an effort to induce antigen-specific immune tolerance, co-administration of immunomodulators with autoantigens has been investigated in an effort to reprogram autoimmunity. To date, identifying immunomodulators that may skew the antigen-specific immune response has been ad hoc at best. To address this need, we utilized splenocytes obtained from mice with experimental autoimmune encephalomyelitis (EAE) in order to determine if certain immunomodulators may induce markers of immune tolerance following antigen rechallenge. Of the immunomodulatory compounds investigated, only dexamethasone modified the antigen-specific immune response by skewing the cytokine response and decreasing T-cell populations at a concentration corresponding to a relevant in vivo dose. Thus, antigen-educated EAE splenocytes provide an ex vivo screen for investigating compounds capable of skewing the antigen-specific immune response, and this approach could be extrapolated to antigen-educated cells from other diseases or human tissues.

Antigen presentation for priming T cells in central system

Generation of myelin antigen-specific T cells is a major event in neuroimmune responses that causes demyelination. The antigen-priming of T cells and its location is important in chronic and acute inflammation. In autoimmune multiple sclerosis, the effector T cells are considered to generate in periphery. However, the reasons for chronic relapsing-remitting events are obscure. Considering mechanisms, a feasible aim of research is to investigate the role of antigen-primed T cells in lupus cerebritis. Last thirty years of investigations emphasize the relevance of microglia and infiltrated dendritic cells/macrophages as antigen presenting cells in the central nervous system. The recent approach towards circulating B-lymphocytes is an important area in the context. Here, we analyze the existing findings on antigen presentation in the central nervous system. The aim is to visualize signaling events of myelin antigen presentation to T cells and lead to the strategy of future goals on immunotherapy research.

Get It through Your Thick Head: Emerging Principles in Neuroimmunology and Neurovirology Redefine Central Nervous System "Immune Privilege"

The central nervous system (CNS) coordinates all aspects of life, autonomic and sentient, though how it has evolved to contend with pathogenic infections remains, to a great degree, a mystery. The skull and cerebrospinal fluid (CSF) provide protection from blunt force contacts, and it was once thought that the blood-brain barrier (BBB) was a fortress that restricted pathogen entry and limited inflammation. Recent studies, however, have caused a revision of this viewpoint: the CNS is monitored by blood-borne lymphocytes, but can use alternative strategies to prevent or resolve many pathogenic challenges. In this Review, we discuss emerging principles that indicate how the CNS is immunologically unique from peripheral tissues. We focus on developments that include glymphatics, recently characterized brain lymphatic vessels, distinctions in innate and adaptive immune strategies, novel points of entry for neurotropic viruses, and, finally, how the periphery can influence CNS homeostasis and immune responses within the brain. Collectively, these attributes demand a re-evaluation of immunity in the brain: not privileged, but distinct.

Changes in Blood B Cell-Activating Factor (BAFF) Levels in Multiple Sclerosis: A Sign of Treatment Outcome

Multiple sclerosis (MS) is mediated primarily by autoreactive T cells. However, evidence suggesting the involvement of humoral immunity in brain diseases has increased interest in the role of B cells and their products during MS pathogenesis. The major survival factor for B cells, BAFF has been shown to play a role in several autoimmune conditions. Elevated BAFF levels have been reported in MS animal model and during MS relapse in patients. Moreover, disease-modifying treatments (DMT) reportedly influence blood BAFF levels in MS patients, but the significance of these changes remains unclear. The present study addresses how blood BAFF levels are associated with the clinical course of relapsing-remitting MS and the effectiveness of DMT and short-term steroid treatment. During a prospective longitudinal follow-up of 2.3 years, BAFF was measured in the blood of 170 MS patients in the stable phase and within 186 relapses. BAFF levels were significantly higher in MS patients compared to healthy controls. However, stable MS patients without relapses exhibited significantly higher BAFF levels than relapsing patients. Treatment with interferon-β and immunosuppressants raised BAFF blood levels. Interestingly, a similar effect was not seen in patients treated with glatiramer acetate. Short-term treatment with high doses of intravenous methylprednisolone did not significantly alter plasma BAFF levels in 65% of relapsing-remitting MS patients. BAFF were correlated weakly but significantly with monocyte and basophil counts, but not with other blood cell types (neutrophils, lymphocytes, or eosinophils) or inflammatory biomarkers. To our knowledge, this is the first report demonstrating that higher blood BAFF levels may reflect a more stable and effective MS treatment outcome. These results challenge hypotheses suggesting that elevated blood BAFF levels are associated with more severe disease presentation and could explain the recent failure of pharmaceutical trials targeting BAFF with soluble receptor for MS treatment.

CNS recruitment of CD8+ T lymphocytes specific for a peripheral virus infection triggers neuropathogenesis during polymicrobial challenge

Although viruses have been implicated in central nervous system (CNS) diseases of unknown etiology, including multiple sclerosis and amyotrophic lateral sclerosis, the reproducible identification of viral triggers in such diseases has been largely unsuccessful. Here, we explore the hypothesis that viruses need not replicate in the tissue in which they cause disease; specifically, that a peripheral infection might trigger CNS pathology. To test this idea, we utilized a transgenic mouse model in which we found that immune cells responding to a peripheral infection are recruited to the CNS, where they trigger neurological damage. In this model, mice are infected with both CNS-restricted measles virus (MV) and peripherally restricted lymphocytic choriomeningitis virus (LCMV). While infection with either virus alone resulted in no illness, infection with both viruses caused disease in all mice, with ∼50% dying following seizures. Co-infection resulted in a 12-fold increase in the number of CD8⁺ T cells in the brain as compared to MV infection alone. Tetramer analysis revealed that a substantial proportion (>35%) of these infiltrating CD8⁺ lymphocytes were LCMV-specific, despite no detectable LCMV in CNS tissues. Mechanistically, CNS disease was due to edema, induced in a CD8-dependent but perforin-independent manner, and brain herniation, similar to that observed in mice challenged intracerebrally with LCMV. These results indicate that T cell trafficking can be influenced by other ongoing immune challenges, and that CD8⁺ T cell recruitment to the brain can trigger CNS disease in the apparent absence of cognate antigen. By extrapolation, human CNS diseases of unknown etiology need not be associated with infection with any particular agent; rather, a condition that compromises and activates the blood-brain barrier and adjacent brain parenchyma can render the CNS susceptible to pathogen-independent immune attack.

There are many CNS diseases, including multiple sclerosis and amyotrophic lateral sclerosis, which have an inflammatory component, though no direct link has been established between incidence and a CNS-resident infectious agent. We reasoned that peripheral immunogens could play a role in CNS disease by inducing an immune response that is “mis-targeted” to the brain. This hypothesis was based on the immunological principle that, while education and activation of naïve cells is an antigen-driven process, recruitment is primarily antigen-independent. We developed a viral co-infection model using measles virus (MV) as a CNS activator and recruiting signal and lymphocytic choriomeningitis (LCMV) as a peripheral immune response initiator. Co-infection with both viruses resulted in significant morbidity and mortality, coincident with LCMV-specific CD8⁺ T cell trafficking to the brain. Death occurred due to edema, despite an apparent absence of LCMV antigens within the brain, and pathogenesis was CD8⁺ T cell-dependent, but perforin-independent. Thus, recruitment of peripherally activated CD8⁺ T cells to the CNS can potentiate neuroinflammation. This work raises the possibility that concomitant immune challenges may be an important cause of the neuroinflammation of some human CNS diseases, perhaps accounting for the inability to identify a discrete pathogenic trigger within affected brain tissues.

The effect of smoking on the symptoms and progression of multiple sclerosis: a review

Multiple sclerosis (MS) is a chronic inflammatory neurodegenerative disorder of the central nervous system with characteristic demyelinating lesions and axonal loss. MS accounts for the most common cause of neurological disability in young adults in the Western world. The clinical manifestations and the course of MS are highly variable. The early stage of the disease is usually characterized by attacks of neurological dysfunction with complete or incomplete recovery, however, with time disability accumulates in many patients. MS is believed to result from an interplay between susceptibility genes and environmental factors, one of which is smoking. Smoking, a worldwide epidemic, can be regarded as an important risk factor for MS particularly because of its modifiable nature in the quest to prevent or temper the disease course in MS as well as providing possible insights into MS pathogenesis. There are also reports that smoking may influence the symptoms and disease progression in patients with MS. The purpose of this article is to review the effects of smoking on MS symptoms and progression. We conclude that (1) although there are some early reports on worsening of MS symptoms by smoking, the existing evidence is insufficient to thoroughly assess the effects of smoking on the myriad of MS symptoms and (2) smoking seems to adversely influence disease progression in MS patients. We also discuss the potential biological mechanisms linking smoking and MS.

Clinical impact of HLA-DR15, a minor population of paroxysmal nocturnal haemoglobinuria-type cells, and an aplastic anaemia-associated autoantibody in children with acquired aplastic anaemia

Aplastic anaemia (AA) is defined as a pancytopenia caused by bone marrow failure, and its pathogenesis is thought to involve autoimmune processes. Several predictive markers of the response to immunosuppressive therapy (IST) have been proposed, which appear to reflect the immune pathophysiology. We prospectively investigated the presence of human leucocyte antigen (HLA)-DR15, a minor population of paroxysmal nocturnal haemoglobinuria (PNH)-type cells, and antibodies to the recently identified autoantigen postmeiotic segregation increased 1 (PMS1) in 103 children with AA enrolled in a multicentre study. In contrast to adults, children with AA did not show an increased frequency of HLA-DR15. In addition, a sensitive flow cytometric assay revealed that children with AA have a much lower prevalence of PNH-type cells (21.4%) than reported for adults with this disease. An immunoblotting assay detected anti-PMS1 antibody in 15 of 103 (14.6%) of the children. Finally, the response rate to IST was not significantly different between patients with and without DR15 (45.5% vs. 54.0%), PNH-type cells (68.2% vs. 53.1%) or anti-PMS1 antibody (40.0% vs. 59.1%). The current study did not confirm a correlation between these markers and the response to IST, suggesting that there is a difference in the pathophysiologies of adult and paediatric AA.

Effect of DAB(389)IL-2 immunotoxin on the course of experimental autoimmune encephalomyelitis in Lewis rats

Activated T cells express the high affinity interleukin 2 receptor (IL-2R also CD25) that binds interleukin 2 (IL-2) and transduces signals important for the proliferation and survival of these cells. We investigated the effect of the genetically engineered immunotoxin DAB(389)IL-2 on experimental autoimmune encephalomyelitis (EAE), an autoimmune disease of the central nervous system (CNS) mediated by activated myelin-reactive T cells. EAE is the most commonly used animal model of the human disease multiple sclerosis (MS). DAB(389)IL-2 is a recombinant fusion product made of a portion of diphtheria toxin, which contains binding and translocation components of the toxin linked to IL-2. The diphtheria toxin targets and kills cells expressing the high affinity IL-2 receptor and has been successfully used in several autoimmune and neoplastic conditions. We observed a significant suppression of guinea-pig spinal cord homogenate (gpSCH)-MBP induced active EAE in Lewis rats at 2 x 1,600 kU of DAB(389)IL-2 given on days 7 and 9 post-immunization and complete suppression with the same dose on days 7, 8 and 9 or 7, 8, 9 and 10 after immunization during the active disease period. There were reduced mononuclear cell infiltrates of CD4(+), CD8(+), CD25(+) and alphabetaTCR(+) T cells in the spinal cord of treated rats. However, treatment at day 11 or 12 post-immunization led to severe, fatal disease. The toxin added to cultures in vitro or injected in vivo suppressed antigen- and mitogen-induced T cell proliferation. DAB(389)IL-2 treatment in vivo or exposure of encephalitogenic T cells in vitro prior to transfer did have a significant inhibitory effect on adoptive transfer EAE. Our data demonstrate that DAB(389)IL-2 immunotoxin can suppress active and passive EAE if applied at specific, early time points, but can have negative consequences at later time points.

The protease inhibitor, Bowman-Birk Inhibitor, suppresses experimental autoimmune encephalomyelitis: a potential oral therapy for multiple sclerosis

Available treatments for multiple sclerosis (MS) require frequent injections and have significant side effects. Proteases generated during inflammation are involved in the induction of tissue damage during inflammatory demyelination in the central nervous system (CNS). The Bowman-Birk Inhibitor (BBI), a soy-derived protease inhibitor with anti-carcinogenic and anti-inflammatory properties, has been shown to be well tolerated in clinical trials for pre-cancerous conditions, such as oral leukoplakia and the inflammatory disease, ulcerative colitis. We hypothesized that BBI may modulate experimental autoimmune encephalomyelitis (EAE), an animal model of MS. The BBI concentrate (BBIC), a soybean extract enriched in BBI, was administered to myelin basic protein (MBP)-immunized Lewis rats by gastric gavage in different treatment regimens, during the induction or the effector phase of disease. BBIC significantly delayed disease onset and suppressed disease severity, clinically and pathologically, in all treatment protocols. Both in vitro and ex vivo, BBIC inhibited MBP-specific proliferation of lymph node cells. BBIC reduced the activity of matrix metalloproteinase (MMP)-2 and -9 in spleen cell supernatants and was detected in the CNS of treated rats. BBIC suppresses EAE, it can be administered orally, and it is safe and relatively inexpensive. It may have a therapeutic role in patients with MS.

Specific antibodies to moesin, a membrane-cytoskeleton linker protein, are frequently detected in patients with acquired aplastic anemia

To identify novel autoantibodies in acquired aplastic anemia (AA), we screened the sera of patients with AA possessing small populations of paroxysmal nocturnal hemoglobinuria (PNH)–type cells for the presence of antibodies (Abs) which recognize proteins derived from a leukemia cell line, UT-7. Immunoblotting using proteins derived from lysates or culture supernatants of UT-7 cells revealed the presence of IgG Abs specific to an 80-kDa protein. Peptide mass fingerprinting identified this 80-kDa protein as moesin. Enzyme-linked immunosorbent assay (ELISA) using recombinant moesin showed high titers of antimoesin Abs in 25 (37%) of 67 patients with AA. Moesin was secreted from several myeloid leukemia cell lines other than UT-7, such as OUN-1 and K562, as an exosomal protein. The presence of antimoesin Abs was significantly correlated with the presence of PNH-type cells and antidiazepam-binding inhibitor-related protein-1 (DRS-1) Abs. Patients with AA that did not show any of these 3 markers tended to respond poorly to immunosuppressive therapy. These findings suggest that a B-cell response to moesin, possibly derived from hematopoietic cells, frequently occurs in patients with AA and that detection of antimoesin Abs in combination with other markers may be useful in diagnosing immune pathophysiology in patients with AA.

Unique gene expression patterns in human T-cell lines generated from multiple sclerosis patients by stimulation with a synthetic MOG peptide

Multiple sclerosis (MS) is an autoimmune disease where T-cells activated against myelin antigens are involved in myelin destruction. Yet, healthy subjects also harbor T-cells responsive to myelin antigens, suggesting that MS patient-derived autoimmune T-cells might bear functional differences from T-cells derived from healthy individuals. We addressed this issue by analyzing gene expression patterns of myelin oligodendrocytic glycoprotein (MOG) responsive T-cell lines generated from MS patients and healthy subjects. We identified 150 transcripts that were differentially expressed between MS patients and healthy controls. The most informative 43 genes exhibited > 1.5-fold change in expression level. Eighteen genes were upregulated including BCL2, lifeguard, IGFBP3 and VEGF. Twenty five genes were down-regulated, including apoptotic activators like TNF and heat shock protein genes. This gene expression pattern was unique to MOG specific T-cell lines and was not expressed in T-cell lines reactive to tetanus toxin (TTX). Our results indicate that activation in MS that promotes T-cell survival and expansion, has its own state and that the unique gene expression pattern that characterize autoreactive T-cells in MS represent a constellation of factors in which the chronicity, timing and accumulation of damage make the difference between health and disease.

Immune Pathophysiology of Aplastic Anemia

Acquired aplastic anemia (AA) is considered an immune-mediated disease because approximately 70% of AA patients improve with immunosuppressive therapy. However, little is known about the inciting antigens or the mechanisms responsible for the destruction of hematopoietic stem cells by immune system attack. Recent advances in immunologic techniques have promoted our understanding of the pathogenesis of AA and have provided evidence that AA is an organ-specific T-cell-mediated disease localized in the bone marrow. Moreover, antibody screening of patients' serum with a complementary DNA library derived from hematopoietic cells has identified several proteins as candidate autoantigens in AA.

Immunohistochemical localization of phosphorylated protein kinase R and phosphorylated eukaryotic initiation factor-2 alpha in the central nervous system of SJL mice with experimental allergic encephalomyelitis

Inflammatory cells enter the CNS and target myelin in multiple sclerosis (MS) and experimental allergic encephalomyelitis (EAE), a model of MS, and inflammation is thought to induce stress responses in the CNS. Protein kinase R (PKR) and eukaryotic initiation factor-2 alpha (eIF2 alpha) undergo phosphorylation in response to stress, and the phosphorylated forms of these proteins play a key role in regulating protein synthesis. The objective of this study was to investigate the expression profile of phospho-PKR and phospho-eIF2 alpha during the course of EAE in order to advance the understanding of the stress response in this disease. In control animals (no encephalitogen with no emulsion; no encephalitogen with emulsion) and in preclinical EAE animals, phospho-PKR immunoreactivity was present in oligodendrocytes and some neurons, whereas, in EAE animals with active disease there was widespread labeling of inflammatory cells, and these cells were present during the recovery period of EAE, albeit to a lesser extent. Double-labeling studies revealed that T cells and a few macrophages were phospho-PKR(+). Phospho-eIF2 alpha immunoreactivity was detected in some oligodendrocytes in hindbrain sections of control animals. In EAE animals with active disease, the number of labeled oligodendrocytes increased, and inflammatory T cells also were labeled. Insofar as phospho-PKR activates nuclear factor-kappa B, it may facilitate cytokines expression by T cells. Alternatively, phospho-PKR and phospho-eIF2 alpha may promote apoptosis as a way to regulate T-cell number in the CNS. The expression of phospho-eIF2 alpha in oligodendrocytes during EAE likely is involved with inhibition of protein translation, which is a protective mechanism used to promote cell survival in response to inflammation.

Diazepam-binding inhibitor-related protein 1: a candidate autoantigen in acquired aplastic anemia patients harboring a minor population of paroxysmal nocturnal hemoglobinuria-type cells

To identify candidate antigens in aplastic anemia (AA), we screened proteins derived from a leukemia cell line with serum of an AA patient and identified diazepam-binding inhibitor-related protein 1 (DRS-1). Enzyme-linked immunosorbent assay (ELISA) revealed high titers of anti-DRS-1 antibodies (DRS-1 Abs) in 27 (38.0%) of 71 AA patients displaying increased paroxysmal nocturnal hemoglobinuria (PNH)-type cells (PNH(+)), 2 (6.3%) of 32 PNH(-) AA patients, 5 (38.5%) of 13 PNH(+) myelodysplastic syndrome (MDS) patients, and none of 42 PNH(-) MDS patients. DRS-1 gene was abundantly expressed in myeloid leukemia cell lines and in CD34(+) cells derived from healthy individuals. Stimulation of T cells from an AA patient displaying high DRS-1 Abs with a putative CD4(+) T-cell epitope (amino acid residues [aa's] 191-204) presented by HLA-DR15, which overlapped with a hot spot (aa's 173-198) of DRS-1 Ab epitopes, gave rise to T cells cytotoxic for L cells (murine fibroblasts) that were transfected with DRB1*1501 and DRS-1. Enzyme-linked immunospot assay demonstrated increased frequency of T-cell precursors specific to the DRS-1 peptide in other HLA-DR15(+) AA patients displaying high DRS-1 Ab titers. These findings indicate that DRS-1 may serve as an autoantigen eliciting immune attack against hematopoietic stem cells in a subset of AA patients characterized by increased PNH-type cells.

Magnetic resonance imaging of labeled T-cells in a mouse model of multiple sclerosis

Multiple sclerosis (MS) is a T cell-mediated autoimmune disease with early lesions characterized by mononuclear cellular infiltrate, edema, demyelination, and axonal loss that contribute to the clinical course of the disease. Experimental autoimmune encephalomyelitis (EAE) in the mouse is a valuable model with a similar disease course to relapsing-remitting MS. The ability to detect the migration of encephalitogenic T cells into the central nervous system in EAE and MS would provide key information on these cells role in the development of lesions observed on magnetic resonance imaging (MRI). T cells were labeled for detection by magnetic resonance imaging using Food and Drug Administration-approved, superparamagnetic iron oxide nanoparticles (Ferumoxides) complexed to poly-L-Lysine (FE-PLL). EAE was induced by adoptive transfer of either labeled or unlabeled T cells. After disease onset, FE-PLL-labeled T cells were detected in the mouse spinal cord using in vivo and ex vivo cellular MRI. Excellent correlation was seen between MRI-visible lesions in the spinal cord and histopathology. The results demonstrate that T cells labeled with FE-PLL can induce EAE disease and can be detected in vivo in the mouse model. The magnetic labeling of cells opens the possibility of monitoring specific cellular phenotypes or pharmacologically or genetically engineered cells by MRI.

Therapeutic potential of peroxisome proliferator-activated receptor agonists for neurological disease

Activation of peroxisome proliferator-activated receptors (PPARs) mediates the insulin-sensitizing effects of thiazolidinediones used for treatment of type 2 diabetes, owing to changes in the transcription and expression of genes influencing carbohydrate and lipid metabolism. However, PPAR activation can have additional effects upon cellular physiology, including anti-proliferative and anti-inflammatory. These effects are observed in many cell types, including brain glial cells and blood lymphocytes, cells whose activation contributes to the initiation and progression of damage occurring in neurological diseases such as Alzheimer's disease (AD) and multiple sclerosis (MS). In view of the need for development of additional therapeutic options, several recent studies have tested the possibility that PPAR agonists would be neuroprotective in these diseases. This paper will summarize data from cell culture experiments and from studies in animal models, demonstrating that PPARgamma agonists can exert neuroprotective effects, thereby providing the basis for the design of clinical trials to test the safety and efficacy of thiazolidinediones in neuroinflammatory conditions such as AD and MS.

IL-12p35-deficient mice are susceptible to experimental autoimmune encephalomyelitis: evidence for redundancy in the IL-12 system in the induction of central nervous system autoimmune demyelination

Experimental autoimmune encephalomyelitis (EAE) serves as a model for multiple sclerosis and is considered a CD4(+), Th1 cell-mediated autoimmune disease. IL-12 is a heterodimeric cytokine, composed of a p40 and a p35 subunit, which is thought to play an important role in the development of Th1 cells and can exacerbate EAE. We induced EAE with myelin oligodendrocyte glycoprotein (MOG) peptide 35-55 (MOG(35-55)) in C57BL/6 mice and found that while IL-12p40-deficient (-/-) mice are resistant to EAE, IL-12p35(-/-) mice are susceptible. Typical spinal cord mononuclear cell infiltration and demyelination were observed in wild-type and IL-12p35(-/-) mice, whereas IL-12p40(-/-) mice had normal spinal cords. A Th1-type response to MOG(35-55) was observed in the draining lymph node and the spleen of wild-type mice. A weaker MOG(35-55)-specific Th1 response was observed in IL-12p35(-/-) mice, with lower production of IFN-gamma. By contrast, a Th2-type response to MOG(35-55) correlated with disease resistance in IL-12p40(-/-) mice. Production of TNF-alpha by microglia, CNS-infiltrating macrophages, and CD4(+) T cells was detected in wild-type and IL-12p35(-/-), but not in IL-12p40(-/-), mice. In addition, NO production was higher in IL-12p35(-/-) and wild-type mice than in IL-12p40(-/-) mice. These data demonstrate a redundancy of the IL-12 system in the induction of EAE and suggest that p40-related heterodimers, such as the recently cloned IL-23 (p40p19), may play an important role in disease pathogenesis.