Multiple sclerosis: an autoimmune disease of multifactorial etiology

Insights into the interplay between Epstein-Barr virus (EBV) and multiple sclerosis (MS): A state-of-the-art review and implications for vaccine development

Background and Aims

Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system (CNS). MS results from an inflammatory process leading to the loss of neural tissue and increased disability over time. The role of Epstein Barr Virus (EBV), as one of the most common global viruses, in MS development has been the subject of several studies. However, many related questions are still unanswered. This study aimed to review the connection between MS and EBV and provide a quick outline of MS prevention using EBV vaccination.

Methods

For this narrative review, an extensive literature search using specific terms was conducted across online databases, including PubMed/Medline, Scopus, Web of Science, and Google Scholar, to identify pertinent studies.

Results

Several studies proved that almost 100% of people with MS showed a history of EBV infection, and there was an association between high titers of EBV antibodies and an increased risk of MS development. Various hypotheses are proposed for how EBV may contribute to MS directly and indirectly: (1) Molecular Mimicry, (2) Mistaken Self, (3) Bystander Damage, and (4) Autoreactive B cells infected with EBV.

Conclusion

Given the infectious nature of EBV and its ability to elude the immune system, EBV emerges as a strong candidate for being the underlying cause of MS. The development of an EBV vaccine holds promise for preventing MS; however, overcoming the challenge of creating a safe and efficacious vaccine presents a significant obstacle.

Oral Cladribine Impairs Intermediate, but Not Conventional, Monocyte Transmigration in Multiple Sclerosis Patients across a Model Blood-Brain Barrier

Multiple sclerosis (MS) is a disease in which the immune system damages components of the central nervous system (CNS), leading to the destruction of myelin and the formation of demyelinating plaques. This often occurs in episodic “attacks” precipitated by the transmigration of leukocytes across the blood-brain barrier (BBB), and repeated episodes of demyelination lead to substantial losses of axons within and removed from plaques, ultimately leading to progressive neurological dysfunction. Within leukocyte populations, macrophages and T and B lymphocytes are the predominant effectors. Among current immunotherapies, oral cladribine’s impact on lymphocytes is well characterised, but little is known about its impact on other leukocytes such as monocytes and dendritic cells (DCs). The aim of this study was to determine the transmigratory ability of monocyte and DC subsets in healthy subjects and untreated and cladribine-treated relapse-remitting MS (RRMS) patients using a well-characterised model of the BBB. Peripheral blood mononuclear cells from subjects were added to an in vitro transmigration assay to assess cell migration. Our findings show that while prior treatment with oral cladribine inhibits the migration of intermediate monocytes, it has no impact on the transmigration of DC subsets. Overall, our data indicate a previously unrecognised role of cladribine on intermediate monocytes, known to accumulate in the brain active MS lesions.

Effects of a Fully Humanized Type II Anti-CD20 Monoclonal Antibody on Peripheral and CNS B Cells in a Transgenic Mouse Model of Multiple Sclerosis

Successful therapy with anti-CD20 monoclonal antibodies (mAbs) has reinforced the key role of B cells in the immunopathology of multiple sclerosis (MS). This study aimed to determine the effects of a novel class of anti-CD20 mAbs on vascular and extravascular central nervous system (CNS)-infiltrating B cells in experimental autoimmune encephalomyelitis (EAE), an animal model of MS. Male hCD20xhIgR3 mice and wild-type C57BL/6 (B6) mice were immunized with human myelin oligodendrocyte glycoprotein (MOG)_1–125 to induce EAE. While hCD20xhIgR3 mice were injected intravenously with an anti-human CD20 mAb (5 mg/kg) (rituximab (a type I anti-CD20 mAb) or obinutuzumab (a type II anti-CD20 mAb), B6 mice received the anti-mouse CD20 antibody 18B12. Neither mAb affected clinical disease or serum antibody levels. Obinutuzumab and rituximab had an impact on splenic and CNS-infiltrated B cells with slightly differential depletion efficacy. Additionally, obinutuzumab had beneficial effects on spinal cord myelination. B cell depletion rates in the 18B12/B6 model were comparable with those observed in obinutuzumab-treated hCD20xhIgR3 mice. Our results demonstrate the usefulness of anti-CD20 mAbs for the modulation of B cell-driven peripheral immune response and CNS pathology, with type II antibodies potentially being superior to type I in the depletion of tissue-infiltrating B cells.

Proteomics of Multiple Sclerosis: Inherent Issues in Defining the Pathoetiology and Identifying (Early) Biomarkers

Multiple Sclerosis (MS) is a demyelinating disease of the human central nervous system having an unconfirmed pathoetiology. Although animal models are used to mimic the pathology and clinical symptoms, no single model successfully replicates the full complexity of MS from its initial clinical identification through disease progression. Most importantly, a lack of preclinical biomarkers is hampering the earliest possible diagnosis and treatment. Notably, the development of rationally targeted therapeutics enabling pre-emptive treatment to halt the disease is also delayed without such biomarkers. Using literature mining and bioinformatic analyses, this review assessed the available proteomic studies of MS patients and animal models to discern (1) whether the models effectively mimic MS; and (2) whether reasonable biomarker candidates have been identified. The implication and necessity of assessing proteoforms and the critical importance of this to identifying rational biomarkers are discussed. Moreover, the challenges of using different proteomic analytical approaches and biological samples are also addressed.

The Impact of SARS-CoV-2 Infection on the Development of Neurodegeneration in Multiple Sclerosis

The novel coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), remains a global challenge. Currently, there is some information on the consequences of COVID-19 infection in multiple sclerosis (MS) patients, as it is a newly discovered coronavirus, but its far-reaching effects on participation in neurodegenerative diseases seem to be significant. Recent cases reports showed that SARS-CoV-2 may be responsible for initiating the demyelination process in people who previously had no symptoms associated with any nervous system disorders. It is presently known that infection of SARS-CoV-2 evokes cytokine storm syndrome, which may be one of the factors leading to the acute cerebrovascular disease. One of the substantial problems is the coexistence of cerebrovascular disease and MS in an individual's life span. Epidemiological studies showed an enhanced risk of death rate from vascular disabilities in MS patients of approximately 30%. It has been demonstrated that patients with severe SARS-CoV-2 infection usually show increased levels of D-dimer, fibrinogen, C-reactive protein (CRP), and overactivation of blood platelets, which are essential elements of prothrombotic events. In this review, the latest knowledge gathered during an ongoing pandemic of SARS-CoV-2 infection on the neurodegeneration processes in MS is discussed.

Ambulatory Neuroproprioceptive Facilitation and Inhibition Physical Therapy Improves Clinical Outcomes in Multiple Sclerosis and Modulates Serum Level of Neuroactive Steroids: A Two-Arm Parallel-Group Exploratory Trial

Background: Only few studies have monitored the potential of physical activity training and physical therapy to modulate the reaction of the endocrine system. In this study, the effect of neuroproprioceptive facilitation and inhibition physical therapy on clinical outcomes and neuroactive steroids production in people with multiple sclerosis was evaluated. Moreover, we were interested in the factors that influence the treatment effect. Methods: In total, 44 patients with multiple sclerosis were randomly divided into two groups. Each group underwent a different kind of two months ambulatory therapy (Motor program activating therapy and Vojta’s reflex locomotion). During the following two months, participants were asked to continue the autotherapy. Primary (serum level of cortisol, cortisone, 7α-OH-DHEA, 7β-OH-DHEA, 7-oxo-DHEA, DHEA) and secondary (balance, cognition and patient-reported outcomes) outcomes were examined three times (pre, post, and washout assessments). Results: In both groups, there is a decreasing trend of 7-oxo-DHEA concentration in post-assessment and 7β-OH-DHEA in washout versus pre-assessment. A higher impact on neuroactive steroids is visible after Vojta’s reflex locomotion. As for clinical outcomes, the Paced Auditory Serial Addition Test and Multiple Sclerosis Impact Scale significantly improved between post-assessment and washout assessment. The improvement was similar for both treatments. Conclusions: Neuroproprioceptive facilitation and inhibition improved the clinical outcomes and led to non-significant changes in neuroactive steroids. Trial registration (NCT04379193).

Obinutuzumab-Induced B Cell Depletion Reduces Spinal Cord Pathology in a CD20 Double Transgenic Mouse Model of Multiple Sclerosis

B cell-depleting therapies have recently proven to be clinically highly successful in the treatment of multiple sclerosis (MS). This study aimed to determine the effects of the novel type II anti-human CD20 (huCD20) monoclonal antibody (mAb) obinutuzumab (OBZ) on spinal cord degeneration in a B cell-dependent mouse model of MS. Double transgenic huCD20xHIGR3 (CD20dbtg) mice, which express human CD20, were immunised with the myelin fusion protein MP4 to induce experimental autoimmune encephalomyelitis (EAE). Both light and electron microscopy were used to assess myelination and axonal pathology in mice treated with OBZ during chronic EAE. Furthermore, the effects of the already established murine anti-CD20 antibody 18B12 were assessed in C57BL/6 wild-type (wt) mice. In both models (18B12/wt and OBZ/CD20dbtg) anti-CD20 treatment significantly diminished the extent of spinal cord pathology. While 18B12 treatment mainly reduced the extent of axonal pathology, a significant decrease in demyelination and increase in remyelination were additionally observed in OBZ-treated mice. Hence, the data suggest that OBZ could have neuroprotective effects on the CNS, setting the drug apart from the currently available type I anti-CD20 antibodies.

Behavioural phenotypes in the cuprizone model of central nervous system demyelination

The feeding of cuprizone (CPZ) to animals has been extensively used to model the processes of demyelination and remyelination, with many papers adopting a narrative linked to demyelinating conditions like multiple sclerosis (MS), the aetiology of which is unknown. However, no current animal model faithfully replicates the myriad of symptoms seen in the clinical condition of MS. CPZ ingestion causes mitochondrial and endoplasmic reticulum stress and subsequent apoptosis of oligodendrocytes leads to central nervous system demyelination and glial cell activation. Although there are a wide variety of behavioural tests available for characterizing the functional deficits in animal models of disease, including that of CPZ-induced deficits, they have focused on a narrow subset of outcomes such as motor performance, cognition, and anxiety. The literature has not been systematically reviewed in relation to these or other symptoms associated with clinical MS. This paper reviews these tests and makes recommendations as to which are the most important in order to better understand the role of this model in examining aspects of demyelinating diseases like MS.

Multiple Sclerosis in Pediatrics: Current Concepts and Treatment Options

Multiple sclerosis (MS) is a chronic, autoimmune, inflammatory, demyelinating disease of the central nervous system. MS is increasingly recognized in the pediatric population, and it is usually diagnosed around 15 years of age. The exact etiology of MS is still not known, although autoimmune, genetic, and environmental factors play important roles in its development, making it a multifactorial disease. The disease in children almost always presents in the relapsing-remittent form. The therapy involves treatment of relapses, and immunomodulatory and symptomatic treatment. The treatment of children with MS has to be multidisciplinary and include pediatric neurologists, ophthalmologists, psychologists, physiotherapists, and if necessary, pediatric psychiatrists and pharmacologists. The basis of MS therapy should rely on drugs that are able to modify the course of the disease, i.e. immunomodulatory drugs. These drugs can be subdivided into two general categories: first-line immunomodulatory therapy (interferon beta-1a, interferon beta-1b, glatiramer acetate) and second-line immunomodulatory therapy (natalizumab, mitoxantrone, fingolimod, teriflunomide, azathioprine, rituximab, dimethyl fumarate, daclizumab). Treatment of relapses involves the use of high intravenous doses of corticosteroids, administration of intravenous immunoglobulins, and plasmapheresis. We summarize here the current available information related to the etiology and treatment options in MS. Early administration of immunomodulatory therapy is beneficial in adults, while more studies are needed to prove their effectiveness in pediatric populations. Therefore, pediatric MS still represents a great challenge for both, the early and correct diagnosis, as well as its treatment.

The beneficial effects of vitamin D3 on reducing antibody titers against Epstein-Barr virus in multiple sclerosis patients

Recently, the relationship between immunoreactivity to Epstein-Barr virus (EBV) and hypo-vitamin D in multiple sclerosis (MS) patients has been described. The aim of this study was to investigate whether vitamin D3 supplementation in MS patients could influence the immune response against latent EBV infection. Forty MS patients were recruited in this study. Twenty-seven patients were supplemented with 50,000 IU/week of vitamin D3 for 6 months and thirteen enrolled as controls. 25-Hydroxyvitamin D (25OHD) levels and IgG titers against EBNA1 and VCA were determined pre- and post-supplementation. All the patients were seropositive for EBV prior to vitamin D supplementation. In this cohort, 22.5% and 47.5% of the MS patients had deficient and insufficient levels of 25OHD, respectively. Our findings confirm that antibody titers against EBV in MS patients rise after the onset of the disease and indicate that vitamin D3 supplementation could limit augmentation of these titers in MS patients.

Modulatory effect of celastrol on Th1/Th2 cytokines profile, TLR2 and CD3+ T-lymphocyte expression in a relapsing-remitting model of multiple sclerosis in rats

Multiple sclerosis (MS) is an autoimmune inflammatory demyelinating disease of brain and spinal cord that has an increasing incidence worldwide and classically presents in a relapsing-remitting form. This study was designed to induce a relapsing-remitting model of experimental autoimmune encephalomyelitis (EAE) to investigate the possible modulatory effect of celastrol on Th1/Th2 cytokines profile, immunohistochemical expression of TLR2, and CD3+T-lymphocytic count. Eighteen female Sprague Dawley rats were divided into 3 groups; where group I served as normal control, group II as EAE+vehicle, and group III as EAE treated by celastrol (1mg/kg/day, i.p.) started at 10th day till 42nd day post-immunization. The clinical score of rats in group II (EAE+vehicle) was relapsed after the re-challenge at the 35th day post-immunization and exhibited significant positive association with serum TNF-α, NF-κB expression and nitrites levels in brain and spinal cord, and CD3+ T-lymphocytic count in brain tissues while serum IL-10 showed significant negative association. Treatment of EAE by celastrol caused amelioration of the clinical score and inhibited the relapse. It caused significant shift in cytokines profile from Th1 by decrease in TNF-α towards Th2 pattern by increase in IL-10. Moreover, celastrol treatment resulted in significant reduction in NF-κB expression, nitrites levels, as well as immunohistochemical expression of TLR2 and CD3+ T-lymphocytic count. The beneficial effect of celastrol was further confirmed histopathologically by reduction in H&E score. Collectively, these results provide a promising pre-clinical evidence and conclusion about use of celastrol in treatment of multiple sclerosis that must be accessed in further clinical studies.

The therapeutic effects of MSc1 nanocomplex, synthesized by nanochelating technology, on experimental autoimmune encephalomyelitic C57/BL6 mice

Purpose

Currently approved therapies for multiple sclerosis (MS) at best only slow down its progression. Therefore, it is necessary to utilize novel technologies in order to synthesize smart multifunctional structures. In the present study, for the first time we evaluated the therapeutic potential of MSc1 nanocomplex, which was designed based on novel nanochelating technology.

Materials and methods

MSc1 cell-protection capacity, with and without iron bond, was evaluated against hydrogen peroxide (H₂O₂)-induced oxidative stress in cultured rat pheochromocytoma-12 cells. The ability of MSc1 to maintain iron bond at pH ranges of 1–7 was evaluated. Nanocomplex toxicity was examined by estimating the intraperitoneal median lethal dose (LD₅₀). Experimental autoimmune encephalomyelitic mice were injected with MSc1 14 days after disease induction, when the clinical symptoms appeared. The clinical score, body weight, and disease-induced mortality were monitored until day 54. In the end, after collecting blood samples for assessing hemoglobin and red blood cell count, the brains and livers of the mice were isolated for hematoxylin and eosin staining and analysis of iron content, respectively.

Results

The results showed that MSc1 prevented H₂O₂-induced cell death even after binding with iron, and it preserved its bond with iron constant at pH ranges 1–7. The nanocomplex intraperitoneal LD₅₀ was 1,776.59 mg/kg. MSc1 prompted therapeutic behavior and improved the disabling features of experimental autoimmune encephalomyelitis, which was confirmed by decreased clinical scores versus increased body mass and 100% survival probability. It did not cause any adverse effects on hemoglobin or red blood cell count. Histopathological studies showed no neural loss or lymphocyte infiltration in MSc1-treated mice, while the hepatic iron content was also normal.

Conclusion

These results demonstrate that MSc1 could be a promising beneficial novel agent and has the capacity to be evaluated in further studies.

Extracellular Vesicles in Multiple Sclerosis: What are They Telling Us?

Extracellular vesicles (EVs) are membrane-bound particles secreted by almost all cell types. They are classified depending on their biogenesis and size into exosomes and microvesicles or according to their cell origin. EVs play a role in cell-to-cell communication, including contact-free cell synapsis, carrying active membrane proteins, lipids, and genetic material both inside the particle and on their surface. They have been related to several physiological and pathological conditions. In particular, increasing concentrations of EVs have been found in many autoimmune diseases including multiple sclerosis (MS). MS is a central nervous system (CNS) demyelinating disease characterized by relapsing of symptoms followed by periods of remission. Close interaction between endothelial cells, leukocytes, monocytes, and cells from CNS is crucial for the development of MS. This review summarizes the pathological role of EVs in MS and the relationship of EVs with clinical characteristics, therapy, and biomarkers of the disease.

Cytokine production profiles in chronic relapsing-remitting experimental autoimmune encephalomyelitis: IFN-γ and TNF-α are important participants in the first attack but not in the relapse

Multiple sclerosis (MS) is a chronic demyelinating disease often displaying a relapsing-remitting course of neurological manifestations that is mimicked by experimental autoimmune encephalomyelitis (EAE) in animal models of MS. In particular, NOD mice immunized with myelin oligodendrocyte glycoprotein peptide 35-55 develop chronic relapsing-remitting EAE (CREAE). To elucidate the mechanisms that cause MS relapse, we investigated the histopathology and cytokine production of spleen cells and mRNA expression levels in the central nervous system (CNS) of CREAE mice. During the first attack, inflammatory cell infiltration around small vessels and in the subarachnoid space was observed in the spinal cord. Spleen cell production and mRNA expression in the CNS of several cytokines, including IFN-γ, TNF-α, IL-6, IL-17, and CC chemokine ligand 2 (CCL2), were higher in CREAE mice than in controls. Afterwards, parenchymal infiltration and demyelination were observed histologically in the spinal cord and corresponded with the more severe clinical symptoms of the first and second relapses. IL-17 and CCL2, but not IFN-γ, TNF-α, or IL-6, were also produced by spleen cells during recurrences. Our results suggested that the immune mechanisms in relapses were different from those in the first attack for CREAE. Further investigation of CREAE mechanisms may provide important insights into successful therapies for human relapsing-remitting MS.

Molecular grafting onto a stable framework yields novel cyclic peptides for the treatment of multiple sclerosis

Multiple sclerosis (MS) is an inflammatory disease of the central nervous system (CNS) and is characterized by the destruction of myelin and axons leading to progressive disability. Peptide epitopes from CNS proteins, such as myelin oligodendrocyte glycoprotein (MOG), possess promising immunoregulatory potential for treating MS; however, their instability and poor bioavailability is a major impediment for their use clinically. To overcome this problem, we used molecular grafting to incorporate peptide sequences from the MOG_35–55 epitope onto a cyclotide, which is a macrocyclic peptide scaffold that has been shown to be intrinsically stable. Using this approach, we designed novel cyclic peptides that retained the structure and stability of the parent scaffold. One of the grafted peptides, MOG3, displayed potent ability to prevent disease development in a mouse model of MS. These results demonstrate the potential of bioengineered cyclic peptides for the treatment of MS.

Serum mercury level and multiple sclerosis

Exposure to heavy metals has been associated to a higher incidence of multiple sclerosis. In this work, we present a possible relationship between serum mercury levels and development of multiple sclerosis in Isfahan, the third largest city in Iran. Seventy-four patients affected by multiple sclerosis were retrieved from multiple sclerosis (MS) clinic in Isfahan, Iran. By matching sex and age, 74 healthy volunteers were chosen as control group. Blood samples were collected and serum mercury content was determined. Serum mercury level in MS patients was significantly higher than controls (9.6 ± 10.17 vs. 5.7 ± 8.6, P = 0.037). Concerning all MS patients, serum mercury value was significantly higher than the mercury concentration founded in control subjects {odd ratio: 2.39 (CI, 1.96-2.94), P = 0.00}. Serum mercury level is higher in MS patients with odd ratio equal to 2.39 compared with healthy individuals. It may reveal that high mercury levels in serum might help MS development in susceptible individuals. More studies with larger sample size are needed to confirm this hypothesis.

Targeting TNF for Treatment of Cancer and Autoimmunity

Tumor necrosis factor-alpha (TNF-alpha) was first isolated two decades ago as a macrophageproduced protein that can effectively kill tumor cells. TNF-alpha is also an essential component of the immune system and is required for hematopoiesis, for protection from bacterial infection and for immune cell-mediated cytotoxicity. Extensive research, however, has revealed that TNF-alpha is one of the major players in tumor initiation, proliferation, invasion, angiogenesis and metastasis. The proinflammatory activities link TNF-alpha with a wide variety of autoimmune diseases, including psoriasis, inflammatory bowel disease, rheumatoid arthritis, systemic sclerosis, systemic lupus erythematosus, multiple sclerosis, diabetes and ankylosing spondylitis. Systemic inhibitors of TNF such as etanercept (Enbrel) (a soluble TNF receptor) and infliximab (Remicade) and adalimumab (Humira) (anti-TNF antibodies) have been approved for the treatment inflammatory bowel disease, psoriasis and rheumatoid arthritis. These drugs, however, exhibit severe side effects and are expensive. Hence orally active blockers of TNF-alpha that are safe, efficacious and inexpensive are urgently needed. Numerous products from fruits, vegetable and traditional medicinal plants have been described which can suppress TNF expression and TNF signaling but their clinical potential is yet uncertain.

Androgen depletion increases the efficacy of bone marrow transplantation in ameliorating experimental autoimmune encephalomyelitis

Bone marrow transplantation (BMT) potentially represents a novel therapy for the amelioration and even cure for multiple sclerosis (MS). It has important advantages over immunosuppressive drug treatments because, while effecting broad-based ablation of the immune system and autoreactive cells, it provides an important means for overcoming the resultant immunodeficiency, while possibly restoring self-tolerance. However, both of these benefits are predicated on a functional thymus that undergoes profound age-induced atrophy from puberty. Reversal of thymic atrophy has been achieved by several procedures, including removal of sex steroids by surgical or chemical (LHRH agonist) castration. Using a murine model of MS, experimental autoimmune encephalomyelitis (EAE), we combined BMT with androgen depletion to induce immune regeneration, and investigated the kinetics of increased thymic function on immune reconstitution and disease reduction. We show that androgen depletion significantly increased the efficacy of BMT to ameliorate the clinical signs of EAE while concurrently restoring the periphery with increased naive and regulatory lymphocytic populations. Upon rechallenge, mice with a regenerated thymus had a slower onset of clinical symptoms compared with mice undergoing BMT only. These results suggest that thymic regeneration strategies may be used as a complement to conventional BMT protocols for the treatment of MS.

Expression of the inhibitor of apoptosis protein family in multiple sclerosis reveals a potential immunomodulatory role during autoimmune mediated demyelination

A failure of autoreactive T cells to undergo apoptosis may contribute to the pathogenesis of multiple sclerosis (MS). The role of the inhibitor of apoptosis (IAP) family of anti-apoptotic proteins such as X-linked IAP (XIAP), human inhibitor of apoptosis-1 (HIAP-1), human inhibitor of apoptosis-2 (HIAP-2), neuronal apoptosis inhibitory protein (NAIP) and Survivin in relapsing–remitting, secondary-progressive, primary-progressive or benign forms of MS is unclear. We report here that expression of the IAP family of genes in peripheral blood samples and brain tissues from MS cases support a role for differential regulation of these potent anti-apoptotic proteins in the pathology of MS. XIAP mRNA and protein levels were elevated in peripheral blood mononuclear cells from patients with active disease relative to normal subjects. In patients with active MS, HIAP-1 and HIAP-2 mRNA levels were elevated in resting T cells while NAIP mRNA was increased in whole blood. In post-mortem MS brain tissue, XIAP and HIAP-1 in myelin lesions were co-localized with microglia and T cells, respectively. Only in primary-progressive patients was Survivin expression elevated suggestive of a distinct pathological basis for this subtype of MS. Taken together, these results suggest that patterns of inhibitor of apoptosis expression in immune cells may have value in distinguishing between MS subtypes and offer insight into the mechanisms responsible for their distinct clinical courses.

Association of MBP peptides with Hsp70 in normal appearing human white matter

Multiple Sclerosis is an autoimmune disease directed against myelin proteins. The etiology of MS is poorly defined though, with no definitive causative agent yet identified. It has been hypothesized that MS may be a multifactorial disease resulting in the same end product: the destruction of myelin by the immune system. In this report we describe a potential role for heat shock proteins in the pathogenesis of MS. We isolated Hsp70 from the normal appearing white matter of both MS and normal human brain and found this was actively associated with, among other things, immunodominant MBP peptides. Hsp70-MBP peptide complexes prepared in vitro were shown to be highly immunogenic, with adjuvant-like effects stimulating MBP peptide-specific T cell lines to respond to normally sub-optimal concentrations of peptide. This demonstration of a specific interaction between Hsp70 and different MBP peptides, coupled with the adjuvanticity of this association is suggestive of a possible role for Hsp70 in the immunopathology associated with MS.

Anti-myelin oligodendrocyte glycoprotein B-cell responses in multiple sclerosis

Humoral auto-immunity to the myelin oligodendrocyte glycoprotein (MOG) is likely involved in the pathogenesis of multiple sclerosis (MS). In 44 MS patients and 30 controls, Ig-producing B cells were identified by their isotype and as MOG-specific spot-forming cells (SFC). Peripheral anti-MOG antibodies were assayed in ELISA as well as anti-butyrophilin antibodies to investigate for molecular mimicry. MS patients had significantly higher levels of IgA- and MOG-SFC than controls, as well as significantly higher antibody responses to MOG and butyrophilin. These data provide added support for the implication of anti-MOG humoral immunity in the pathophysiology of MS, and suggest a balance of systemic (anti-self) and mucosal (environment-modulated) immune reactions in an attempt at regulating the pathogenic specific immune response.

Granulocyte macrophage colony-stimulating factor: a new putative therapeutic target in multiple sclerosis

Experimental autoimmune encephalomyelitis (EAE), a model for multiple sclerosis, can be induced by immunization with a number of myelin antigens. In particular, myelin oligodendrocyte glycoprotein, a central nervous system (CNS)-specific antigen expressed on the myelin surface, is able to induce a paralytic MS-like disease with extensive CNS inflammation and demyelination in several strains of animals. Although not well understood, the egress of immune cells into the CNS in EAE is governed by a complex interplay between pro and antiinflammatory cytokines and chemokines. The hematopoietic growth factor, granulocyte macrophage colony-stimulating factor (GM-CSF), is considered to play a central role in maintaining chronic inflammation. The present study was designed to investigate the previously unexplored role of GM-CSF in autoimmune-mediated demyelination. GM-CSF(-/)- mice are resistant to EAE, display decreased antigen-specific proliferation of splenocytes, and fail to sustain immune cell infiltrates in the CNS, thus revealing key activities for GM-CSF in the development of inflammatory demyelinating lesions and control of migration and/or proliferation of leukocytes within the CNS. These results hold implications for the pathogenesis of inflammatory and demyelinating diseases and may provide the basis for more effective therapies for inflammatory diseases, and more specifically for multiple sclerosis.

Brain-derived gangliosides suppress the chronic relapsing-remitting experimental autoimmune encephalomyelitis in NOD mice induced with myelin oligodendrocyte glycoprotein peptide

Chronic relapsing-remitting experimental autoimmune encephalomyelitis (CREAE) induced with myelin oligodendrocyte glycoprotein peptides 35-55 (MOG(35-55)) in NOD mice was successfully treated with brain-derived gangliosides (GA). The GA treatment suppressed the development and severity of CREAE, both clinically and histologically. Spleen cells from the GA-treated mice displayed markedly inhibited levels of MOG(35-55) specific proliferation and interferon-gamma production. Delayed-type hypersensitivity reactions to MOG(35-55) were suppressed by the GA treatment. GA modulate various T cell effector functions in CREAE and may be an effective therapeutic agent for autoimmune demyelinating diseases such as multiple sclerosis.

Optic neuritis and multiple sclerosis

PURPOSE

Review of the association between optic neuritis (ON) and multiple sclerosis (MS).

RESULTS

MS often presents as acute unilateral ON. While it is clear that many patients with ON suffer from a generalized disease of the central nervous system that will go on to clinically definite MS (CDMS), it is also clear that others do not. With more and more well-informed patients and the emerging pharmacotheraphy for MS, the distinction between those patients with ON who have MS and those who do not, has become more important than ever before. Recently, a large randomized clinical trial on patients with ON or other clinically isolated syndromes suggestive of MS and evidence of prior subclinical demyelination on magnetic resonance imaging of the brain, found that treatment with recombinant interferon-beta-1a is beneficial by reducing the development of CDMS.

CONCLUSION

Ophthalmologists should refer their patients with acute ON to a neurologist for MS-directed investigations and decisions regarding early institution of disease modifying therapy.

Humoral and cellular immune responses to Copolymer 1 in multiple sclerosis patients treated with Copaxone

Humoral and cellular immune responses were followed in multiple sclerosis patients treated with Copolymer 1 (Cop1, glatiramer acetate, Copaxone) who participated in three different clinical trials. All patients (130) developed Cop1 reactive antibodies, which peaked at 3 months after initiation of treatment, decreasing at 6 months and remaining low. IgG1 antibody levels were 2-3-fold higher than those of IgG2. The proliferative response of Peripheral Blood Mononuclear Cells (PBMC) to Cop1 was initially high and gradually decreased during treatment. Antibodies and T cell responses to MBP were low and did not change significantly during the treatment. The humoral and cellular immunological responses to Cop1 do not correlate with the side effects and do not affect its therapeutic activity. The preferential production of IgG1 over IgG2 antibodies may indicate that Th2 responses are involved in mediating the clinical effect of Cop1.

Transcriptional analysis of multiple sclerosis brain lesions reveals a complex pattern of cytokine expression

Multiple sclerosis (MS) is a common and severe neurological disorder associated with an autoimmune response directed against myelin components within the CNS. Lymphocyte activation, extravasation, and recruitment, as well as effector function, involves the turning on and off of a number of genes, thus triggering specific transcriptional pathways. The characterization of the transcriptome in MS lesions should provide a better understanding of the mechanisms that generate and sustain the pathogenic immune response in this disease. Here we performed transcriptional profiling of 56 relevant genes in brain specimens from eight MS patients and eight normal controls by kinetic RT-PCR. Results showed a high transcriptional activity for the gene coding for myelin basic protein (MBP); however, it was not differentially expressed in MS samples, suggesting that remyelination is an active process also in the noninflammatory brain. CD4 and HLA-DRalpha transcripts were dramatically increased in MS as compared with controls. This reveals a robust MHC class II up-regulation and suggests that Ag is being presented locally to activated T cells. Although analysis of cytokine and cytokine receptor genes expression showed predominantly increased levels of several Th1 molecules (TGF-ss, RANTES, and macrophage-inflammatory protein (MIP)-1alpha) in MS samples, some Th2 genes (IL-3, IL-5, and IL-6/IL-6R) were found to be up-regulated as well. Similarly, both proinflammatory type (CCR1, CCR5) and immunomodulatory type (CCR4, CCR8) chemokine receptors were differentially expressed in the MS brain. Overall, our data suggest a complex regulation of the inflammatory response in human autoimmune demyelination.

Anti-IL-12 antibody prevents the development and progression of multiple sclerosis-like relapsing--remitting demyelinating disease in NOD mice induced with myelin oligodendrocyte glycoprotein peptide

Treatment with monoclonal anti-IL-12 antibody injected on day 0, 7 and 10 after immunization with myelin oligodendrocyte glycoprotein (MOG) peptide 35-55 in NOD mice resulted in significant suppression of the development and the severity of the chronic relapsing-remitting experimental autoimmune encephalomyelitis (EAE) both clinically and histologically. The spleen cells from anti-IL-12 antibody treated mice displayed markedly inhibited MOG35-55 specific proliferation and IFN-gamma production. MOG35-55 specific antibody production was enhanced by anti-IL-12 antibody treatment. These results suggest that IL-12 is critically involved in the pathogenesis of MOG-induced EAE and that antibody to IL-12 could be an effective therapeutic agent in the clinical treatment of autoimmune demyelinating diseases such as multiple sclerosis (MS).

The concept of specific immune treatment against autoimmune diseases

Copolymer 1 (Cop 1, Copaxone) is a synthetic amino acid copolymer effective in suppression of experimental allergic encephalomyelitis (EAE). The suppressive effect of Cop 1 in EAE is not restricted to a certain species, disease type or encephalitogen used for EAE induction. In phases II and III clinical trials Cop 1 was found to slow progression of disability and reduce the relapse rate in exacerbating-remitting multiple sclerosis (MS) patients. To extend this concept we have more recently shown that a similar approach is possible in the case of myasthenia gravis. We used two myasthenogenic T cell epitopes of the human acetylcholine receptor alpha-subunit and demonstrated that they are capable of triggering peripheral blood lymphocytes of the majority (>80%) of myasthenic patients tested. Both single amino acid analogs, and a dual analog composed of the tandemly arranged two single amino acid analogs were able to inhibit in vitro proliferative responses of T cell lines, and in vivo priming of lymph node cells. The dual analog inhibited experimental autoimmune myasthenia gravis even when the mice were treated fourteen days after the injection of the pathogenic T cell line.

B Cell Repertoire Diversity and Clonal Expansion in Multiple Sclerosis Brain Lesions

Multiple sclerosis (MS) lesions in the CNS are characterized by disseminated demyelination with perivascular infiltrates of macrophages, T cells, and B cells. To investigate the origin and characteristics of the B cell population found in MS plaque tissue, we performed molecular studies in 10 MS patients and 4 non-MS control samples. Ig transcripts from the perivascular infiltrated brain lesions were analyzed by complementary-determining region 3 spectratyping to ascertain the B cell heavy chain gene rearrangement repertoire expressed in MS brains. Significant rearrangement diversity and deviation from the normal Ig heavy (H) chain repertoire was observed. The cloning and sequencing of RT-PCR products from families VH1 and VH4 showed a correlation with the profiles obtained by spectratyping. Generally, restricted spectratyping patterns concurred with repetition of in-frame complementary-determining region 3 identical sequences. The analysis of heavy chain variable (VH), diversity (D), and joining (JH) gene segments revealed the increased usage of VH1–69, VH4–34, and VH4–39. Similarly, gene segments from families D2, D3, and JH4 were over-represented. The presence of restricted patterns of rearranged Ig mRNA within the plaque lesion suggests that Ab production in the demyelinating plaque is a local phenomenon and supports the idea that in MS an Ag-driven immune response might be responsible for demyelination.

IgG subclass switching is associated with the severity of experimental autoimmune encephalomyelitis induced with myelin oligodendrocyte glycoprotein peptide in NOD mice

We have recently shown that a single dose of the myelin oligodendrocyte glycoprotein (MOG) peptide 35-55 produces a relapsing-remitting demyelinating disease similar to multiple sclerosis (MS) in Lewis rats. In this study we have assessed the possibility that a subclass of anti-MOG35-55 antibodies influences the clinical outcome of these diseases by examining the classes and isotypes of anti-MOG35-55 antibody produced during the course of MOG35-55-induced demyelinating disease in NOD mice. Following immunization, 7 of the 21 injected mice had only mild diseases, while the 14 others had severe progressive and/or relapsing-remitting diseases. There were no differences in anti-MOG35-55 IgG, IgA, IgM, IgG1, IgG2a, and IgG3 antibody titers between the severe and mild symptoms groups. High levels of IgG2b antibody to MOG35-55 were detected in all mice with severe symptoms. In contrast, none of the mice which contracted a mild disease produced anti-MOG35-55 IgG2b. These results suggest that in NOD mice, the IgG2b antibody response to MOG35-55 is associated with the severity of this MS-like demyelinating disease.

Neurotrophic ACTH4-9 analogue therapy normalizes electroencephalographic alterations in chronic experimental allergic encephalomyelitis

Chronic experimental allergic encephalomyelitis (CEAE) is an established experimental model for multiple sclerosis (MS). The demyelinating lesions in the white matter of the central nervous system observed in CEAE and in MS are accompanied by various neurophysiological alterations. Among the best defined electrophysiological abnormalities are the changes in event-related potentials, in particular evoked potentials involving the spinal cord, i.e. motor and sensory evoked potentials. Less familiar are the changes observed in the electroencephalogram of CEAE-affected animals, which are also encountered in the human equivalent, MS. In the present experiment we evaluated the therapeutic value of a neurotrophic peptide treatment [H-Met(O2)-Glu-His-Phe-D-Lys-Phe-OH, an ACTH4-9 analogue] and its effect on the delayed flash visual evoked potentials (VEP) and power spectra of the electroencephalogram, during a 17-week follow-up of CEAE. CEAE animals treated with the neurotrophic peptide were protected against the development of neurological symptoms during the course of the demyelinating syndrome. VEPs of animals suffering from CEAE showed a delay of the latencies of the late components which was significantly counteracted by peptide treatment. The peak-to-peak amplitude of the VEP afterdischarge recorded from CEAE animals was significantly increased during the course of CEAE and correlated closely with the progression of the myelinopathy. Furthermore, CEAE animals showed an increase of electroencephalogram (EEG) beta activity of up to 500% as compared with the age-matched control group. This increase in beta power mainly consisted of a prevailing 20-21 Hz peak, a frequency that normally is not dominant in control EEG recordings of the rat during passive wakefulness. All these electrophysiological phenomena were absent in ACTH4-9 analogue-treated animals. The present findings underscore the potential importance of a neurotrophic peptide treatment in the pharmacotherapy of central demyelinating syndromes, and possibly of MS.

Bystander suppression of experimental autoimmune encephalomyelitis by T cell lines and clones of the Th2 type induced by copolymer 1

The synthetic amino acid copolymer, copolymer 1 (Cop 1) induces T suppressor (Ts) lines/clones, which are confined to the Th2 pathway, cross react with myelin basic protein (MBP), but not with other myelin antigens on the level of Th2 cytokine secretion. Nevertheless, Cop 1 Ts cells inhibited the IL-2 response of a proteolipid protein (PLP) specific line. Furthermore, Cop 1 Ts cells ameliorated EAE induced by two unrelated encephalitogenic epitopes of PLP: p139-151 and p178-191, that produced different forms of disease. This bystander suppression demonstrated by the Cop 1 Ts cells may explain the therapeutic effect of Cop 1 in EAE and MS.

Induction of a multiple sclerosis-like disease in mice with an immunodominant epitope of myelin oligodendrocyte glycoprotein

Myelin oligodendrocyte glycoprotein (MOG) is postulated to be a target autoantigen in multiple sclerosis (MS). Here we investigated the encephalitogenicity of an immunodominant epitope of MOG, peptide 35-55, in various strains of mice. An MS-like disease was induced in NOD/Lt mice (H-2g7) and C57BL/6 mice (H-2b) by a single injection of MOG35-55 in CFA. The disease followed a relapsing-remitting course in NOD/Lt mice, whereas C57BL/6 mice developed a chronic paralytic disease. Histologically, the disease in both strains was characterized by cellular infiltration and multifocal demyelination in the CNS. Significant DTH type reactions to MOG35-55 were only seen in MOG-susceptible animals, with the NOD/Lt mice showing the strongest responses. Susceptible mice also showed specific antibody responses to MOG35-55 but not to a panel of other MOG peptides. These results provide further evidence for the role of MOG as a highly autoantigenic molecule capable of inducing severe demyelinating disease.

Remyelination: cellular and gene therapy

Dysfunctional myelination or oligodendroglial abnormalities play a prominent role in a vast array of pediatric neurological diseases of genetic, inflammatory, immunological, traumatic, ischemic, developmental, metabolic, and infectious causes. Recent advances in glial cell biology have suggested that effective remyelination strategies may, indeed, be feasible. Evidence for myelin repair is accumulating in various experimental models of dysmyelinating and demyelinating disease. Attempts at remyelination have either been directed towards creating myelin de novo from exogenous sources of myelin-elaborating cells or promoting an intrinsic spontaneous remyelinating process. Ultimately, some disorders of myelin may require multiple repair strategies, not only the replacement of dysfunctional cells (oligodendroglia) but also the delivery or supplementation of gene products (i.e., growth factors, immune modulators, metabolic enzymes). Although primary oligodendrocytes or oligodendroglial precursors may be effective for glial cell replacement in certain discrete regions and circumstances and although various genetic vectors may be effective for the delivery of therapeutic molecules, multipotent neural stem cells may be most ideally suited for both gene transfer and cell replacement on transplantation into multiple regions of the central nervous system under a wide range of pathological conditions. We propose that, by virtue of their inherent biological properties, neural stem cells possess the multifaceted therapeutic capabilities that many diseases characterized by myelin dysfunction in the pediatric population may demand.

Chronic varied stress modulates experimental autoimmune encephalomyelitis in Wistar rats

Stress disturbs homeostasis by altering the equilibrium of various hormones which have a significant impact on immune responses. Few studies have examined the influence of stressors on autoimmune disease in animal models. In our work, we studied the effects of long-term exposure (14 days) to chronic varied stress (CVS) in a model of experimental autoimmune encephalomyelitis (EAE) in Wistar rats. We studied whether the exposure to CVS before or after the immune challenge would correlate with differences in the clinical course of the disease. We also examined whether the CVS would modulate the magnitude of the cellular or the humoral immune response. We observed opposite effects on the clinical signs in animals stressed before or after the immune challenge. The clinical signs of the disease were attenuated in animals stressed before but not after the immune challenge. Relationships were found in the modulation of the clinical severity related to the time of exposure to the CVS, the histological alterations and the proliferative results. Stressed animals with milder clinical signs presented an exacerbated humoral response against myelin antigens while stressed animals with more severe clinical symptoms exhibited a significantly diminished one. Besides, we detected the presence of specific IgG1 associated with the exposure to CVS before the induction of EAE. Our results show that, depending on the timing of the exposure of Wistar rats to the CVS, the neuroendocrine disbalance favors a more pronounced humoral or cellular profile of the response.

A conformational study of the human and rat encephalitogenic myelin oligodendrocyte glycoprotein peptides 35-55

Myelin oligodendrocyte glycoprotein (MOG), is considered an important central-nervous system-specific target autoantigen for primary demyelination in autoimmune diseases like multiple sclerosis. We have recently demonstrated that MOG or its derived peptide, MOG-(35-55)-peptide, are able to produce in animals, clinicopathologic signs that mimic multiple sclerosis. The rat MOG sequence spanning amino acids 35-55 [rMOG-(35-55)-peptide] differs from the human sequence [hMOG-(35-55)-peptide] by a single amino acid substitution, i.e. Pro42-->Ser. Mice injected with rMOG-(35-55)-peptide showed severe inflammation and demyelination throughout the central nervous system but, interestingly, mice injected with hMOG-(35 -55)-peptide showed only a few foci of mild inflammation with no demyelination. Circular dichroism and nuclear magnetic resonance spectroscopy have been used to structurally characterise the bioactive peptides hMOG-(35-55)-peptide and rMOG-(35-55)-peptide. In 0.1 M K2HPO4/KOH, 90% H2O/D2O solutions, these derived peptides have been shown, by NMR spectroscopy, to adopt detectable levels of short-range structure in equilibrium with unfolded conformers. On addition of 2,2,2-trifluoro-(2H3)ethanol, rMOG-(35-55)-peptide and hMOG-(35-55)-peptide adopt folded structures which have nuclear Overhauser enhancements characteristic of a poorly defined alpha-helix over residues 44-51. There are some indications of secondary structure also evident in the N-terminal region of rMOG-(35-55)-peptide. CD spectroscopy has revealed that in aqueous solution both peptides are unfolded but in 2.2.2-trifluoroethanol and, at micellar concentrations of sodium dodecyl sulfate, rMOG-(35-55)-peptide and, to a lesser extent, hMOG-(35-55)-peptide adopt helical conformations. In contrast, at non-micellar concentrations of SDS rMOG-(35-55)-peptide and hMOG-(35-55)-peptide adopt, according to CD spectroscopy, a beta-structure indicating that the peptides change conformation depending on the microenvironment of the amino acids.

Cop 1 as a candidate drug for multiple sclerosis

Copolymer 1 (Cop 1), a synthetic copolymer of amino acids, is very effective in suppression of experimental autoimmune encephalomyelitis (EAE), the animal model for multiple sclerosis (MS). Cop 1 was found incapable of inducing EAE, yet it suppressed EAE in a variety of animal species, including primates. The immunological cross-reaction between the myelin basic protein (MBP) and Cop 1 serves as the basis for the suppressive activity of Cop 1 in EAE, by the induction of antigen-specific suppressor cells and competition with MBP for binding to major histocompatibility complex (MHC) molecules. Clinical trials with Cop 1, both Phase II and Phase III, were performed in relapsing-remitting (E-R) patients. The latter, a two-year multicenter double blind trial with 251 participating patients was conducted at 11 leading medical centers in the USA. It demonstrated a significant beneficial effect of Cop 1 in both diminishing the rate of exacerbations and improving the clinical status. The side effects of Cop 1 were only minimal. The cumulative results indicate that Cop 1 is a promising candidate drug for multiple sclerosis.

New insights into the mechanism of action of copolymer 1 in experimental allergic encephalomyelitis and multiple sclerosis

Copolymer 1 is a synthetic amino acid copolymer, effective in suppression of experimental allergic encephalomyelitis (EAE) induced in a variety of species. Copolymer 1 can suppress both acute and chronic relapsing EAE induced by either whole brain homogenate or the purified encephalitogens myelin basic protein (MBP) and proteolipid protein (PLP). Thus, the suppressive effect of copolymer 1 in EAE is a general phenomenon and is not restricted to a certain species, the disease type, or the encephalitogen used for EAE induction. The suppressive activity of copolymer 1 is, however, limited to EAE, and copolymer 1 has no nonspecific immunological activity. On the other hand, a marked degree of immunological cross-reactivity in both the cellular and humoral immune responses was demonstrated between MBP and copolymer 1. This cross-reactivity may be the underlying mechanism for the specific suppressive effect of copolymer 1 in EAE. In vivo and in vitro studies using both murine and human cell cultures suggest that the mechanism for copolymer 1 activity in EAE and multiple sclerosis involves, as an initial step, the binding of copolymer 1 to the major histocompatibility complex class II molecules on antigen-presenting cells. Following this step, two pathways may be activated: (1) induction of antigen-specific suppressor T cells by determinants shared between MBP and copolymer 1, or (2) competition with MBP and other myelin-associated antigens, PLP and myelin oligodendrocyte glycoprotein, for the activation of effector T cells. These two mechanisms can act either separately or in concert to interfere in the autoimmune processes that lead to the neurological damage in EAE and multiple sclerosis.

Functional and neurophysiological evidence of the efficacy of trophic pharmacotherapy using an adrenocorticotrophic hormone4-9 analog in experimental allergic encephalomyelitis, an animal model of multiple sclerosis

Chronic experimental allergic encephalomyelitis (CEAE) is a well-established animal model for the human syndrome, multiple sclerosis. CEAE has striking histological, electrophysiological and clinical analogies with multiple sclerosis and is a valuable animal model for the preclinical pharmacotherapeutical development of new putative therapeutic agents. In this paper, we describe a neurotrophic repair approach in Lewis rats suffering from CEAE. The neurotrophic peptide used is a degradation resistant adrenocorticotrophic hormone4-9 analog. The development of CEAE was examined using a combination of clinical, functional and electrophysiological parameters including somatosensory and motor evoked potentials. The latencies and amplitudes of the various evoked potentials can provide quantitative, objective data regarding the involvement of different nerve tracts in CEAE and the effectiveness of the neurotrophic peptide. Repeated subcutaneous injections of the neurotrophic peptide suppressed the development of CEAE-related clinical symptoms, markedly improved motor performance and reduced the reaction time upon thermal stimulation as compared to saline-treated CEAE animals during a 17 week follow-up study. Prolonged onset latencies of corticomotor evoked potentials and peak latencies of somatosensory evoked potentials due to the demyelination were normalized upon peptide treatment. In addition, peptide treatment substantially prevented total blocking of the corticomotor pathway in CEAE-animals and reduced the attenuation of sensory evoked potentials-related peak amplitudes as compared to saline-treated animals. The functional and electrophysiological improvements observed in CEAE-animals treated with the adrenocorticotrophic hormone4-9 analog, suggest that a neurotrophic repair approach could be of great value to promote the restoration of function in a disabling demyelinating disorder.

Copolymer 1 inhibits chronic relapsing experimental allergic encephalomyelitis induced by proteolipid protein (PLP) peptides in mice and interferes with PLP-specific T cell responses

Copolymer 1 (Cop 1) is a synthetic amino acid copolymer effective in suppression of experimental allergic encephalomyelitis (EAE) and developed as a candidate drug for multiple sclerosis (MS). In the present study, we induced chronic relapsing (CR)-EAE in (SJL/J X BALB/c)F1 mice by either whole spinal cord homogenate or two synthetic peptides of proteolipid protein (PLP), p139-151 and p178-191. When Cop 1 was added to the encephalitogenic inoculum, mice were almost completely resistant to disease induction. T cell lines to p139-151 and p178-191 were specific to these peptides. Their antigen-specific responses were inhibited by Cop 1 in a dose-dependent manner, while their polyclonal response to the superantigen staphylococcal enterotoxin A (SEA) was not affected by Cop 1. Using biotinylated PLP derivatives, we demonstrated that the two PLP peptides bound to I-A(s) molecules, and that their binding was completely inhibited by unlabelled Cop 1. Furthermore, Cop 1 could displace the PLP peptides from the MHC binding site. These results support the potential of Cop 1 as a broad-spectrum drug for MS.

Prevention of experimental autoimmune encephalomyelitis in Lewis rats by a novel fungal source of gamma-linolenic acid

The effects of oral administration of linoleic- and gamma-linolenic-acid-rich oils on the clinical and histopathological manifestations of experimental autoimmune encephalomyelitis (EAE) were investigated in Lewis rats 7 d post-inoculation. gamma-Linolenic-acid-rich fungal (Mucor javanicus) oil at 500 mg/kg body weight abrogated clinical and histological signs of EAE although at doses of 200 and 1000 mg/kg body weight it was only effective in delaying the onset of clinical disease. Linoleic-acid-rich safflower-seed (Carthamus tinctorius) oil at 500, 750 and 1000 mg/kg body weight decreased the severity of clinical EAE disease in a dose-dependent manner. The effects in healthy animals of orally administered gamma-linolenic-acid-rich fungal oil (500 mg/kg body weight) and linoleic-acid-rich safflower-seed oil (1000 mg/kg body weight) on splenic lymphocyte proliferative responses to the T-cell mitogen concanavalin-A (Con A), membrane fatty acid composition and lymphocyte sub-sets were also studied. Both treatments enhanced the T-cell proliferative response to Con A. There was no significant effect on the proportion of splenic CD8+ or CD4+ lymphocytes. Compositional studies on splenic phosphoglyceride fatty acids of oil-treated animals suggest the above responses were associated with increases in spleen dihomo-gamma-linolenic and arachidonic acids.

Identification of murine loci associated with susceptibility to chronic experimental autoimmune encephalomyelitis

B10.RIII mice develop chronic and relapsing experimental autoimmune encephalomyelitis (EAE) after immunization with the myelin basic protein (MBP) peptide 89-101. The disease is associated with the major histocompatibility complex (MHC) (eae1). We have now investigated the importance of non-MHC regions for the EAE susceptibility in a cross between RIIIS/J and B10.RIII mice which share the MHC region but differ in disease susceptibility. Linkage analysis using microsatellite markers spanning the genome identified a region (eae2) on chromosome 15 which showed linkage to disease (P = 0.0002). Our data also suggest linkage to a second region (eae3) on chromosome 3 (P = 0.0024), and provide evidence for locus interactions between eae2 and eae3. These results provide clues to the genetic basis of multiple sclerosis.

T cell receptor gamma delta repertoire is skewed in cerebrospinal fluid of multiple sclerosis patients: molecular and functional analyses of antigen-reactive gamma delta clones

To study the relevance of gamma delta T cells in multiple sclerosis (MS) we analyzed the T cell receptor (TCR) gamma delta repertoire and the antigen reactivity of gamma delta clones isolated from cerebrospinal fluid (CSF). In T cell cultures derived from CSF we found an increased percentage of V delta 1+ cells as compared to peripheral blood of the same donors. Phenotypic analysis of cells from MS CSF with V gamma- and V delta-specific monoclonal antibodies (mAb) showed that the V delta 1 chain is most frequently associated with gamma chains belonging to the V gamma 1 family. Sequence analysis of TCR genes revealed heterogeneity of junctional regions in both delta and gamma genes indicating polyclonal expansion. gamma delta clones were established and some recognized glioblastoma, astrocytoma or monocytic cell lines. Stimulation with these targets induced serine esterase release and lymphokine expression characteristic of the TH0-like phenotype. Remarkably, these tumor-reactive gamma delta cells were not detected in the peripheral blood using PCR oligotyping, but were found in other CSF lines independently established from the same MS patient. Altogether, these results demonstrate that in the CSF there is a skewed TCR gamma delta repertoire and suggest that gamma delta cells reacting against brain-derived antigens might have been locally expanded.

High incidence of spontaneous autoimmune encephalomyelitis in immunodeficient anti-myelin basic protein T cell receptor transgenic mice

We have generated TCR transgenic mice (T/R+) specific for myelin basic protein (MBP) and crossed them to RAG-1-deficient mice to obtain mice (T/R-) that have T cells expressing the transgenic TCR but no other lymphocytes. Both T/R+ and T/R- mice carry, in the lymph nodes and spleen, large numbers of the potentially encephalitogenic CD4+ anti-MBP T cells. These cells respond to MBP in vitro but show no signs of activation in vivo. Nevertheless, approximately 14% of H-2u T/R+ and 100% of H-2u T/R- mice developed spontaneous experimental autoimmune encephalomyelitis (EAE) within 12 months. These data indicate that EAE can be mediated by CD4+ anti-MBP T cells in the absence of any other lymphocytes and that nontransgenic lymphocytes that are present in T/R+ but absent in T/R- mice have a protective effect. The data also suggest that spontaneous EAE may be triggered by an in situ activation of CD4+ anti-MBP cells in the nervous system.