Anti-ganglioside antibodies in multiple sclerosis

Anti-Glycolipid Antibody Examination in Five EAE Models and Theiler's Virus Model of Multiple Sclerosis: Detection of Anti-GM1, GM3, GM4, and Sulfatide Antibodies in Relapsing-Remitting EAE

Anti-glycolipid antibodies have been reported to play pathogenic roles in peripheral inflammatory neuropathies, such as Guillain-Barré syndrome. On the other hand, the role in multiple sclerosis (MS), inflammatory demyelinating disease in the central nervous system (CNS), is largely unknown, although the presence of anti-glycolipid antibodies was reported to differ among MS patients with relapsing-remitting (RR), primary progressive (PP), and secondary progressive (SP) disease courses. We investigated whether the induction of anti-glycolipid antibodies could differ among experimental MS models with distinct clinical courses, depending on induction methods. Using three mouse strains, SJL/J, C57BL/6, and A.SW mice, we induced five distinct experimental autoimmune encephalomyelitis (EAE) models with myelin oligodendrocyte glycoprotein (MOG)35-55, MOG92-106, or myelin proteolipid protein (PLP)139-151, with or without an additional adjuvant curdlan injection. We also induced a viral model of MS, using Theiler's murine encephalomyelitis virus (TMEV). Each MS model had an RR, SP, PP, hyperacute, or chronic clinical course. Using the sera from the MS models, we quantified antibodies against 11 glycolipids: GM1, GM2, GM3, GM4, GD3, galactocerebroside, GD1a, GD1b, GT1b, GQ1b, and sulfatide. Among the MS models, we detected significant increases in four anti-glycolipid antibodies, GM1, GM3, GM4, and sulfatide, in PLP139-151-induced EAE with an RR disease course. We also tested cellular immune responses to the glycolipids and found CD1d-independent lymphoproliferative responses only to sulfatide with decreased interleukin (IL)-10 production. Although these results implied that anti-glycolipid antibodies might play a role in remissions or relapses in RR-EAE, their functional roles need to be determined by mechanistic experiments, such as injections of monoclonal anti-glycolipid antibodies.

Anti-glycan antibodies: roles in human disease

Carbohydrate-binding antibodies play diverse and critical roles in human health. Endogenous carbohydrate-binding antibodies that recognize bacterial, fungal, and other microbial carbohydrates prevent systemic infections and help maintain microbiome homeostasis. Anti-glycan antibodies can have both beneficial and detrimental effects. For example, alloantibodies to ABO blood group carbohydrates can help reduce the spread of some infectious diseases, but they also impose limitations for blood transfusions. Antibodies that recognize self-glycans can contribute to autoimmune diseases, such as Guillain-Barre syndrome. In addition to endogenous antibodies that arise through natural processes, a variety of vaccines induce anti-glycan antibodies as a primary mechanism of protection. Some examples of approved carbohydrate-based vaccines that have had a major impact on human health are against pneumococcus, Haemophilus influeanza type b, and Neisseria meningitidis. Monoclonal antibodies specifically targeting pathogen associated or tumor associated carbohydrate antigens (TACAs) are used clinically for both diagnostic and therapeutic purposes. This review aims to highlight some of the well-studied and critically important applications of anti-carbohydrate antibodies.

The role of Sphingolipids in myelination and myelin stability and their involvement in childhood and adult demyelinating disorders

Multiple sclerosis (MS) represents the most common demyelinating disease affecting the central nervous system (CNS) in adults as well as in children. Furthermore, in children, in addition to acquired diseases such as MS, genetically inherited diseases significantly contribute to the incidence of demyelinating disorders. Some genetic defects lead to sphingolipid alterations that are able to elicit neurological symptoms. Sphingolipids are essential for brain development, and their aberrant functionality may thus contribute to demyelinating diseases such as MS. In particular, sphingolipidoses caused by deficits of sphingolipid-metabolizing enzymes, are often associated with demyelination. Sphingolipids are not only structural molecules but also bioactive molecules involved in the regulation of cellular events such as development of the nervous system, myelination and maintenance of myelin stability. Changes in the sphingolipid metabolism deeply affect plasma membrane organization. Thus, changes in myelin sphingolipid composition might crucially contribute to the phenotype of diseases characterized by demyelinalization. Here, we review key features of several sphingolipids such as ceramide/dihydroceramide, sphingosine/dihydrosphingosine, glucosylceramide and, galactosylceramide which act in myelin formation during rat brain development and in human brain demyelination during the pathogenesis of MS, suggesting that this knowledge could be useful in identifying targets for possible therapies.

Emergence and significance of carbohydrate-specific antibodies

Carbohydrate-specific antibodies are widespread among all classes of immunoglobulins. Despite their broad occurrence, little is known about their formation and biological significance. Carbohydrate-specific antibodies are often classified as natural antibodies under the assumption that they arise without prior exposure to exogenous antigens. On the other hand, various carbohydrate-specific antibodies, including antibodies to ABO blood group antigens, emerge after the contact of immune cells with the intestinal microbiota, which expresses a vast diversity of carbohydrate antigens. Here we explore the development of carbohydrate-specific antibodies in humans, addressing the definition of natural antibodies and the production of carbohydrate-specific antibodies upon antigen stimulation. We focus on the significance of the intestinal microbiota in shaping carbohydrate-specific antibodies not just in the gut, but also in the blood circulation. The structural similarity between bacterial carbohydrate antigens and surface glycoconjugates of protists, fungi and animals leads to the production of carbohydrate-specific antibodies protective against a broad range of pathogens. Mimicry between bacterial and human glycoconjugates, however, can also lead to the generation of carbohydrate-specific antibodies that cross-react with human antigens, thereby contributing to the development of autoimmune disorders.

Antibodies against Gangliosides in Patients with SLE and Neurological Manifestations

Pathogenesis of neuropsychiatric manifestations of systemic lupus erythematosus (SLE) has not been clearly defined, and the search for pathogenic mechanisms has focused on the importance of several autoantibodies. There is increasing evidence that antibodies against gangliosides may have a pathogenic role in some neurological disorders. The aim of the present study was to examine the association between antibodies against gangliosides and neuropsychiatric SLE. We found anti-type II ganglioside antibodies in two out of 32 patients with multiple sclerosis (6.25%) and in 10 out of 60 patients with SLE (16.6%); five of 17 patients with neurological abnormalities also had high levels of these antibodies (29.4%). Five of the 10 patients with SLE and positive antiganglioside antibody assays had only IgM antibodies, three had IgG antibodies and two had both isotypes. By chi-square analysis, the incidence of anti-type II ganglioside antibodies was not significantly higher in patients with symptoms related to the nervous system than in SLE patients without neurological involvement (P > 0.2). No clear correlation was found between antibodies against gangliosides and cardiolipin.

Illuminating vitamin D effects on B cells--the multiple sclerosis perspective

Vitamin D is associated with many immune-mediated disorders. In multiple sclerosis (MS) a poor vitamin D status is a major environmental factor associated with disease incidence and severity. The inflammation in MS is primarily T-cell-mediated, but increasing evidence points to an important role for B cells. This has paved the way for investigating vitamin D effects on B cells. In this review we elaborate on vitamin D interactions with antibody production, T-cell-stimulating capacity and regulatory B cells. Although in vitro plasma cell generation and expression of co-stimulatory molecules are inhibited and the function of regulatory B cells is promoted, this is not supported by in vivo data. We speculate that differences might be explained by the B-cell-Epstein-Barr virus interaction in MS, the exquisite role of germinal centres in B-cell biology, and/or in vivo interactions with other hormones and vitamins that interfere with the vitamin D pathways. Further research is warranted to illuminate this tube-versus-body paradox.

Autoimmune T-cell reactivity to myelin proteolipids and glycolipids in multiple sclerosis

Central nervous system (CNS) myelin, the likely major target of autoimmune attack in multiple sclerosis (MS), contains a number of unique components that are potential targets of the attack. Two classes of molecules that are greatly enriched in CNS myelin compared to other parts of the body are certain types of proteolipids and glycolipids. Due to the hydrophobic nature of both of these classes of molecules, they present challenges for use in immunological assays and have therefore been somewhat neglected in studies of T-cell reactivity in MS compared to more soluble molecules such as the myelin basic proteins and the extracellular domain of myelin oligodendrocyte glycoprotein. This review firstly looks at the makeup of CNS myelin, with an emphasis on proteolipids and glycolipids. Next, a retrospective of what is known of T-cell reactivity directed against proteolipids and glycolipids in patients with MS is presented, and the implications of the findings are discussed. Finally, this review considers the question of what would be required to prove a definite role for autoreactivity against proteolipids and glycolipids in the pathogenesis of MS.

Myalgic encephalomyelitis/chronic fatigue syndrome and encephalomyelitis disseminata/multiple sclerosis show remarkable levels of similarity in phenomenology and neuroimmune characteristics

BACKGROUND

'Encephalomyelitis disseminata' (multiple sclerosis) and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) are both classified as diseases of the central nervous system by the World Health Organization. This review aims to compare the phenomenological and neuroimmune characteristics of MS with those of ME/CFS.

DISCUSSION

There are remarkable phenomenological and neuroimmune overlaps between both disorders. Patients with ME/CFS and MS both experience severe levels of disabling fatigue and a worsening of symptoms following exercise and resort to energy conservation strategies in an attempt to meet the energy demands of day-to-day living. Debilitating autonomic symptoms, diminished cardiac responses to exercise, orthostatic intolerance and postural hypotension are experienced by patients with both illnesses. Both disorders show a relapsing-remitting or progressive course, while infections and psychosocial stress play a large part in worsening of fatigue symptoms. Activated immunoinflammatory, oxidative and nitrosative (O+NS) pathways and autoimmunity occur in both illnesses. The consequences of O+NS damage to self-epitopes is evidenced by the almost bewildering and almost identical array of autoantibodies formed against damaged epitopes seen in both illnesses. Mitochondrial dysfunctions, including lowered levels of ATP, decreased phosphocreatine synthesis and impaired oxidative phosphorylation, are heavily involved in the pathophysiology of both MS and ME/CFS. The findings produced by neuroimaging techniques are quite similar in both illnesses and show decreased cerebral blood flow, atrophy, gray matter reduction, white matter hyperintensities, increased cerebral lactate and choline signaling and lowered acetyl-aspartate levels.

SUMMARY

This review shows that there are neuroimmune similarities between MS and ME/CFS. This further substantiates the view that ME/CFS is a neuroimmune illness and that patients with MS are immunologically primed to develop symptoms of ME/CFS.

Is multiple sclerosis an autoimmune disease?

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS) with varied clinical presentations and heterogeneous histopathological features. The underlying immunological abnormalities in MS lead to various neurological and autoimmune manifestations. There is strong evidence that MS is, at least in part, an immune-mediated disease. There is less evidence that MS is a classical autoimmune disease, even though many authors state this in the description of the disease. We show the evidence that both supports and refutes the autoimmune hypothesis. In addition, we present an alternate hypothesis based on virus infection to explain the pathogenesis of MS.

Evidence for the role of B cells and immunoglobulins in the pathogenesis of multiple sclerosis

The pathogenesis of multiple sclerosis (MS) remains elusive. Recent reports advocate greater involvement of B cells and immunoglobulins in the initiation and propagation of MS lesions at different stages of their ontogeny. The key role of B cells and immunoglobulins in pathogenesis was initially identified by studies in which patients whose fulminant attacks of demyelination did not respond to steroids experienced remarkable functional improvement following plasma exchange. The positive response to Rituximab in Phase II clinical trials of relapsing-remitting MS confirms the role of B cells. The critical question is how B cells contribute to MS. In this paper, we discuss both the deleterious and the beneficial roles of B cells and immunoglobulins in MS lesions. We provide alternative hypotheses to explain both damaging and protective antibody responses.

CD1A and CD1E Gene Polymorphisms are Associated with Susceptibility to Multiple Sclerosis

Multiple sclerosis (MS) is thought to be an autoimmune T-cell-mediated disease directed at myelin antigens of the central nervous system. Besides myelin proteins, lipid components of CNS are supposed to play a role as antigens for T cells in MS. CD1 is a family of MHC-like glycoproteins specialized in capturing and presenting a variety of microbial and self lipids and glycolipids to antigen-specific T cells. CD1-restricted T cells specific for gangliosides and sulfatide have been isolated from subjects with MS and in mice with experimental allergic encephalopathy. We genotyped exon 2 of CD1A and CD1E in 205 MS patients and 223 unrelated healthy controls and determined their association with the presence of anti-ganglioside and anti-sulfatide antibodies. CD1E 01-01 is associated with a reduced risk of MS (OR 0.54, p=0.001); CD1A 02-02 (OR 1.99, p=0.012) or CD1E 02-02 (OR 2.45, p=0.000) with an increased risk. The combination of the genotypes CD1A 02-02 and CD1E 02-02 is present in 90.7% of patients but in only 9.4% controls (OR 94.16, p= 0.000). CD1A and CD1E polymorphisms contribute to the polygenic susceptibility to MS. The functional effects of CD1 polymorphisms are unknown, however changes in CD1 alleles may affect numerous immunological functions.

Molecular and immunogenic features of myelin lipids: incitants or modulators of multiple sclerosis?

Myelin lipids have long been thought to play intriguing roles in the pathogenesis of multiple sclerosis (MS). This review summarizes current understanding of the molecular basis of MS with emphasis on the: (i.) physico-chemical properties, organization and accessibility of the lipids and their distribution within the myelin multilayer; (ii.) characterization of myelin lipid structures, and structure-function relationships relevant to MS mechanisms, and; (iii.) immunogenic and other features of lipids in MS including molecular mimicry, lipid enzyme genetic knockouts, glycolipid-reactive NKT cells, and monoclonal antibody-induced remyelination. New findings associate anti-lipid antibodies with pathophysiological biomarkers and suggest clinical utility. The structure of CD1d-lipid complexed with the lipophilic invariant T cell receptor (iTCR) may be crucial to understanding MS pathogenesis, and design of lipid antigen-specific therapeutics. Novel immuno-modulatory tools for treatment of autoimmune diseases including MS in which there is both constraint of inflammation and stimulation of remyelination are now emerging.

Structure and Biology of Self Lipid Antigens

Self lipid antigens induce selection and expansion of autoreactive T cells which have a role in immunoregulation and disease pathogenesis. Here we review the important biological rules which determine lipid immunogenicity. The impact of lipid structure, synthesis, traffic, membrane distribution and CD1 loading are discussed.

Increased circulating T cell reactivity to GM3 and GQ1b gangliosides in primary progressive multiple sclerosis

We have previously shown that patients with primary progressive multiple sclerosis (MS) have significantly elevated plasma levels of antibody to GM3 ganglioside compared to patients with relapsing-remitting MS, healthy subjects and patients with other neurological diseases. Anti-GM3 antibody levels were elevated also in patients with secondary progressive MS but to a lesser extent than in primary progressive MS. As gangliosides are particularly enriched in the axonal membrane, these findings suggested that antiganglioside immune responses might contribute to the axonal damage in progressive forms of MS. The present study was performed to determine whether peripheral blood T cell responses to GM3 are also increased in progressive MS. Blood was collected from 98 untreated patients with MS (40 with relapsing-remitting, 27 with secondary progressive and 31 with primary progressive MS), 50 healthy subjects and 24 patients with other disorders of the CNS, and reactivity to GM1, GM3, GD1a, GD1b, GD3, GT1b, GQ1b and sulphatide was assessed by 6-day T cell proliferation assays. Increased T cell reactivity to GM3 and GQ1b occurred significantly more often in patients with primary progressive MS than in healthy subjects and patients with other CNS diseases. These findings suggest that ganglioside-specific T cells may contribute to the axonal damage in primary progressive MS.

Serum ganglioside patterns in multiple sclerosis

The relative distribution of gangliosides was determined in the serum of 37 patients with multiple sclerosis (MS) and of 30 healthy subjects. There was a significant increase of GM1 and GD1a, and a decrease of GM3 proportion in the serum of relapsing-remitting MS patients (RRMS) during their first MS attack. The RRMS patients in relapse with a long duration of the disease had a significant decrease of GM1 and an increase of GD1a portion in the serum. An increase of GD1a, one of the major brain neuron ganglioside fraction, suggested the neuron injury in the early and with a long duration RRMS. The finding of an increase of GM1, the main human myelin ganglioside, during the first MS attack in RRMS patients confirms previous evidence for the possible involvement of gangliosides in the early pathological course of demyelination in MS.

Multiple sclerosis is associated with enhanced B cell responses to the ganglioside GD1a

The occurrence and role of autoantibodies to gangliosides and other lipid-containing components of the central nervous system in Multiple Sclerosis (MS) are unsettled. Using sensitive ELISAs, we measured IgG and IgM antibody titers and absorbances to the three major gangliosides GD1a, GD1b and GM1, and to sulfatides, cardiolipin and myelin proteins in paired serum and cerebrospinal fluid (CSF) from patients with untreated MS, optic neuritis (ON), acute aseptic meningo-encephalitis (AM) and other neurological diseases (OND). Twenty-three per cent of 30 MS (P<0.04) and 18% of 32 ON patients (P<0.05) presented elevated IgG antibody titers to GD1a in serum compared to 9% of patients with OND. Six (40%) of the patients with malignant MS had elevated serum IgG antibody titers to GD1a compared to one (6%) of the patients with benign MS (P<0.04). In CSF, elevated IgG antibody titers to GD1a were measured in 13% of MS and 20% of ON patients compared to 4% of patients with OND (P<0. 03 and P<0.02, respectively). The augmented IgG response to GD1a in serum also separated MS from Guillain-Barré syndrome. Compared to OND increased IgM absorbances to sulfatides and cardiolipin were observed in CSF of patients with MS, but also in AM. Elevated IgG antibody titers to myelin proteins were found more often in MS patients' serum and MS, ON and AM patients' CSF compared to OND. The data implicate that among the multitude of enhanced B-cell responses occurring in MS and ON, that directed to GD1a is common and more discriminative, and should be evaluated in future MS treatment studies.

Increased circulating antiganglioside antibodies in primary and secondary progressive multiple sclerosis

Plasma samples from 70 patients with multiple sclerosis (MS), 41 patients with other neurological diseases (OND), and 38 healthy subjects were examined for antibodies against gangliosides GM1, GM3, GD1a, GD1b, and GD3 using enzyme-linked immunosorbent assays. The percentages of subjects with increased anti-GM3 responses were significantly higher in the primary progressive MS (56.3%) and secondary progressive MS (42.9%) groups than in the relapsing-remitting MS (2.9%), healthy subject (2.6%), and OND (14.6%) groups. Elevated antiganglioside antibodies may be secondary to axonal damage or may be a cause of axonal damage and accumulating disability in progressive MS. In either case, they may serve as a marker of axonal damage in MS.

Gangliosides do not elicit experimental autoimmune encephalomyelitis in Lewis rats and SJL mice

We have studied the ability of gangliosides to induce or ameliorate experimental autoimmune encephalomyelitis (EAE) in Lewis rat and SJL mice. None of the animals immunized with gangliosides with or without methylated bovine serum albumin (MBSA) developed EAE. Gangliosides were also administered simultaneously with PLP, but they did not alter the incidence or severity of EAE. However, high doses of MBSA could ameliorate or prevent EAE in a dose-dependent manner. T-cell responses towards gangliosides and antiganglioside antibodies were also studied. In conclusion, in these experimental models gangliosides have no encephalitogenic activity and do not alter the course of EAE.

Different antiganglioside antibody pattern between relapsing-remitting and progressive multiple sclerosis

INTRODUCTION

Multiple sclerosis (MS) is an autoimmune disorder, but an unique antigen has not been found. Antiganglioside antibodies (AGA) have been reported in MS, nevertheless, a clinical significance of AGA in MS has not been established. The aims of this study were to study AGA in sera of MS patients and to investigate relationships between AGA and clinical course of MS.

MATERIAL AND METHODS

42 patients with MS who fulfilled the criteria of clinically definite disease (59% RRMS, 21% SPMS, 20% PPMS), 89 patients with systemic lupus erythematosus and 36 healthy controls were studied. A modification of previously described ELISA techniques was used to estimate serum IgG and IgM anti-GM1, asialoGM1 and anti-GD1a antibodies.

RESULTS

47.6% of the patients showed AGA reactivity. Anti-GM1 was found in 38% of MS patients, anti-asialoGM1 in 23.8% and anti-GD1a in 33.3%. IgG was the isotype more commonly found. A correlation between presence of AGA and progressive disease and between anti-GD1a and PPMS was found.

CONCLUSIONS

The presence of AGA in MS patients is elevated. In contrast with the results of others authors, a strong correlation between AGA and progressive disease is showed in our study.

Cerebrospinal fluid antiganglioside antibodies in patients with AIDS

In this study the presence of brain antiganglioside antibodies in the cerebrospinal fluid (CSF) of patients with HIV infection was analysed. CSF samples were collected from 45 patients with AIDS and from 45 anti-HIV negative subjects, 15 of whom presented aseptic meningitis. Nineteen AIDS patients had clinically well-documented encephalopathy. Thirteen of these patients had white matter lesions shown by magnetic resonance imaging (MRI). Both IgG and IgM antiganglioside antibodies were detected by immunostaining on thin layer chromatography plates in three CSF samples from AIDS patients with progressive encephalopathy with signs of a diffuse demyelination, as revealed by MRI. Two of these CSF samples reacted specifically with GM3, GM1 and GD1a and one with GD1a. In none of the HIV infected patients without demyelinating encephalopathy, but with opportunistic infections or cerebral lymphoma, nor in the anti-HIV negative control subjects were antiganglioside antibodies detected. No association with JCV DNA, CMV DNA, EBV DNA, detected by nested PCR, nor HIV antigen p24 was found. These findings show the presence of brain antiganglioside antibodies in the CSF of AIDS patients for the first time. However, the findings do not suggest relating the presence of these antibodies to HIV encephalopathy or particular viral agents, but indicate that the antibodies are detectable in subjects with progressive encephalopathy with a diffuse demyelination.

The pathogenesis of multiple sclerosis. Additional considerations

Multiple sclerosis (MS) is acquired as a systemic "trait" by individuals who are genetically susceptible. This condition does not involve the central nervous system (CNS) and is characterized by a state of hyperactive immunocompetent responsiveness. It develops as the result of an antigenic challenge by a viral protein, either from a viral infection or a vaccination. In order for MS to become a disease affecting the CNS, it is necessary for the blood-brain barrier's (BBB) impermeability to be altered. This is now a fully recognized fact. As a result of this change, the MS lesion, which consists of edema and inflammation occurs. It may but need not lead to demyelination. Several mechanisms can cause this increased permeability of the BBB. The role of the immune system, and in particular of T lymphocytes in initiating and continuing the process of lesion formation remains extremely controversial. In fact, there are unanswered questions regarding the actual target of MS: is it the myelin sheath itself or its forming cell, the oligodendrocyte, or is it the BBB itself leading to bystander demyelination? The role of mild, concussional trauma to the CNS in producing the alteration of the BBB and therefore acting as a trigger or facilitator in the development or enlargement of MS lesions in the CNS, is based on considerable clinical, neuropathological and experimental evidence. Along with another viral infection, it must be one of the commonest causes of progression of MS, and quite often leads to the onset of the clinical manifestations of an hitherto asymptomatic condition.

CSF and serum ganglioside antibody patterns in MS

The authors determined CSF and serum IgG and IgM antibodies to seven gangliosides in 48 patients with multiple sclerosis. Differing ganglioside antibody patterns in CSF but not serum allowed to reclassify 93% of MS patients correctly when compared to patients with Guillain-Barré syndrome or neuroborreliosis. This suggest that the antibody patterns are neither random nor alike in inflammatory diseases of the nervous system. CSF ganglioside antibody titres were found to be different for patients with relapsing remitting (RRMS; n = 35) and chronic progressive (CPMS; n = 13) multiple sclerosis. Our study reveals characteristic ganglioside antibody patterns in MS and confirms previous evidence of disturbed immunoregulation in MS.

Autoantibodies against Forssman glycolipids in Graves' disease and Hashimoto's thyroiditis

Sera from patients with Graves' disease and Hashimoto's thyroiditis have been shown to react with the Forssman glycolipid antigen (Gb5) using the techniques of high performance thin-layer chromatography (HPTLC) immunostaining and ELISA. Human monoclonal antibodies (MoAbs) have been prepared by fusion of human myeloma with peripheral lymphocytes from patients with Graves' disease. A MoAb, TRMo-4, reacted strongly and specifically with Gb5. These results suggest that anti-Forssman antibody may be involved in the pathogenesis of these autoimmune diseases. The detection of anti-Forssman glycolipid antibody may provide a useful means for clinical diagnosis and therapy.

Induction of demyelination by intraneural injection of antibodies against sulfoglucuronyl paragloboside

Sulfoglucuronyl glycolipids (SGGLs) carry the glucuronyl 3-sulfate (HNK-1) epitope which is recognized by monoclonal IgM paraproteins from patients with demyelinating polyneuropathy. We report that intraneural injections of rat anti-SGGL antibodies induce demyelination in rat sciatic nerve, along with mild to moderate clinical symptoms. Morphologically, vesiculation and loosening of the myelin sheath were observed 3 h postinjection, followed by extensive demyelination and macrophage infiltration after 4 days. Since the anti-SGGL antibodies showed no cross-reactivity with other components in rat sciatic nerve, these results indicate that SGGLs alone can serve as the target antigens in demyelinating neuropathy.

Gangliosides: the relevance of current research to neurosurgery

Gangliosides are complex glycolipids found on the outer surface of most cell membranes: they are particularly concentrated in tissues of the nervous system. Gangliosides form part of the immunological identity of mammalian cells and are involved in a variety of cell-surface phenomena such as cell-substrate binding and receptor functions. In tumorous tissue, the ganglioside composition is altered, sometimes in direct proportion to the degree of malignancy. The literature on the glycosphingolipid composition and immunology of intracranial tumors is reviewed. Some gangliosides induce neuritogenesis and exhibit a trophic effect on nerve cells grown in vitro. In vivo, a particular ganglioside, GM1, reduces cerebral edema and accelerates recovery from injury (traumatic and ischemic) to the peripheral and central nervous systems of laboratory animals. Preliminary clinical studies have shown that treatment with gangliosides may have corresponding effects on lesions of the human peripheral nervous system. Gangliosides have not been tested in human subjects with brain injury.

Neuropsychiatric manifestations of systemic lupus erythematosus: the value of anticardiolipin, antigangliosides and antigalactocerebrosides antibodies

In an attempt to find a serological marker for neuropsychiatric manifestations (NPM) of SLE, sera from 66 patients (classified in three groups, according to their NPM-defined, probable and without NPM) were analysed by ELISA for IgG and IgM anticardiolipin, antigangliosides and antigalactocerebrosides antibodies. A strong correlation was found between IgM antigangliosides and antigalactocerebrosides antibodies and NPM, but not with IgG class. IgM and IgG antibodies anticardiolipin were not correlated with NPM in this study. Both IgM antigangliosides and antigalactocerebrosides antibodies disappeared in seven patients with definite but clinically inactive NPM. The analysis of these autoantibodies showed an important role predictive for NPM in SLE; the negative test decreases the chance of the NPM.

Cerebrospinal fluid and serum antiphospholipid antibodies in multiple sclerosis, Guillain-Barré syndrome and systemic lupus erythematosus

Immunoglobulins isotypes (IgG and IgM) for myelin basic protein (MBP), cerebrosides (CER), gangliosides (GANG) and cardiolipin (CARD) were detected in the cerebrospinal fluid (CSF) from 33 patients with multiple sclerosis (MS), 18 with Guillain-Barré syndrome (GBS) and 30 with systemic lupus erythematosus (SLE). In MS patients occurred positive and significant levels of IgG-MBP in 51.5% (p less than 0.05) and IgM-MBP in only 18.2%, IgG-CARD in 46.2%, as long as CER and GANG were detected in almost 20%. From serum samples of MS patients 20.6% presented IgG-MBP, while 53% showed positive levels for IgM-MBP. The CSF analysis of patients with GBS showed that 56.3% revealed IgG-MBP (p less than 0.05), 53% for IgM-MBP, 38.5% for IgG-CER and 23% for IgM-CER, while 50% of patients had IgG-CARD, as long as 31% also had IgG-GANG. The serum evaluation from 14 patients showed that 18.8% had positive concentrations of IgG-MBP and 56.3% presented IgM-MBP (p less than 0.05). Except for 50% of patients with SLE who presented positive CSF levels of IgG-CARD, only 24.1% had positive levels of IgG-MBP. We believe that the presence of antiphospholipid antibodies in CSF of the above mentioned diseases occurred as immune epiphenomena, but their appearance would permit the maintenance of and perpetuate the immune event.

Immunoelectron microscopical labelling of a glycolipid in the envelopes of brain cell-derived budding viruses, Semliki Forest, influenza and measles, using a monoclonal antibody directed chiefly against galactocerebroside resulting from Semliki Forest virus infection

Neurotropic RNA budding viruses such as Semliki Forest virus (SFV), influenza and measles were each grown in identical mouse brain cell cultures. Positive immunoelectron microscopical labelling with gold was seen in the envelope of these viruses using an anti-SFV derived glycolipid monoclonal antibody (MAb), 373 shown to be directed chiefly against galactocerebroside. The results indicate that each enveloped virus grown from the same cell type contains the same glycolipid in its envelope. The presence of common glycolipids derived from the host cell in the envelopes of various enveloped budding viruses may play a significant role in the pathogenesis of virus induced, immune mediated CNS autoimmunity and demyelination, particularly in multiple sclerosis (MS).

Multiple sclerosis: cell-mediated immunity to human brain gangliosides

Cell-mediated immunity (CMI) to myelin components has been implicated in Multiple Sclerosis (MS) pathogenesis: two targets were suggested, Myelin Basic Protein with controversial results and, more recently, gangliosides. In order to investigate their possible involvement, we have performed Leukocyte Migration inhibition (LMI) tests in the presence of human brain gangliosides. Thirty nine MS patients (twenty four being "definite", according to McDonald and Halliday's classification), twenty nine patients with Other Neurological Diseases (OND), thirty six patients with Inflammatory diseases (ID) and forty healthy controls were tested. MS patients were divided into two groups, depending on the clinical stage of the disease. The mean migration inhibition percentage of the MS-attack group was found to be significantly different from the four others (p less than 0.01) (24.4 +/- 16.2 versus 10.9 +/- 8.5 in MS without attack, 4.4 +/- 12.9 in OND, 3.9 +/- 13.9 in ID and 11.1 +/- 12.1 in healthy subjects). LMI to gangliosides is therefore significantly increased during the attack stage in MS. These results support the notion of a Delayed Type Hypersensitivity to these glycolipids during the active stage of the disease.

Monoclonal IgMs with anti-Gal(beta 1-3) GalNAc activity in lower motor neuron disease; identification of glycoprotein antigens in neural tissue and cross-reactivity with serum immunoglobulins

IgM monoclonal antibodies (M-proteins) with anti-Gal(beta 1-3)GalNAc and anti-Gal(beta 1-3)GlcNAc activity that bind to gangliosides GD1b and GM1, from two patients with lower motor neuron disease were tested for binding to neural glycoproteins. The M-proteins bound to several glycoproteins in the central and peripheral nervous system including to some in the non-myelin or axonal fraction only. Peanut agglutinin (PNA) which is specific for Gal(beta 1-3)GalNAc, bound to the same protein bands. Since serological studies revealed that the M-proteins were complexed to IgG, serum immunoglobulins were tested for presence of Gal(beta 1-3)GalNAc epitopes. Both PNA and the M-proteins bound to immunoglobulin heavy and light chains, suggesting that the circulating M-proteins bind to Gal(beta 1-3)GalNAc on other immunoglobulins. These studies indicate that in addition to gangliosides the M-proteins might bind to Gal(beta 1-3)GalNAc bearing glycoproteins in vivo and that carbohydrate epitopes on immunoglobulins might have a role in the development and regulation of autoantibodies which cross-react with neural antigens and may cause neurological disease.

Identification and characterization of anti-conjugated azelaic acid antibodies in multiple sclerosis

Human sera from patients with multiple sclerosis (MS) were tested using an enzyme-linked immunosorbent assay (ELISA) method on well plates coated with various dicarboxylic acid (C4 to C10) protein conjugates. Specific immunological binding was found with an azelaic acid (AzeA, C9) conjugate. The antibody titer was higher in the sera from the patients in acute relapse than with the progressive form, and higher than that from sera of patients with other neurological diseases and healthy subjects. Modifications of coating concentrations and of antibody dilutions, and experiments with preadsorption enabled determination of binding specificity. Competition experiments with related conjugates demonstrated that the AzeA residue was 167 times better recognized by antibodies from MS patients in acute relapse than those from controls. The suberic and sebasic acid conjugates which only differ from the AzeA conjugate by one methylene group were less well-recognized by MS sera (11 and 47 times, respectively) than the conjugate AzeA-BSA.

The role of the thymus in multiple sclerosis

The presence of numerous changes in T lymphocyte activity found in MS patients points to the involvement of the thymus in multiple sclerosis. The etiophathogenetic mechanism of MS is probably an autoimmune reaction that is triggered by a viral infection caused by one or more viruses and that perpetuates itself, causing the disease to progress. It has been proved that the thymus maintains its immunocompetence even in adulthood and that it has a role in the pathogenesis in several autoimmune diseases. In exacerbations of MS there is a decrease in T suppressor lymphocytes while histological and lymphocyte subset changes have been demonstrated in the thymus of MS patients. The lymphocyte response to mitogens is also depressed in MS. The clinical results of thymectomy in MS are not uniform and are on the whole inconclusive, probably through the lack of criteria of selection of patients for surgical treatment. We consider that the morphological and functional study of the thymus biopsy specimen should supply the appropriate criteria of suitability for surgical treatment.

Antisera to the ganglioside GM1 do not have anti-myelin or anti-axon activities in vitro

Four antisera to the ganglioside GM1 were tested for effects on myelin and axons when applied to mouse spinal cord-dorsal root ganglia explant cultures. None of the antisera to GM1 caused myelination inhibition or demyelination, while an antiserum to galactocerebroside caused both. Antisera to GM1 did not inhibit axonal outgrowth or destroy mature outgrowth zone axons, while an antiserum to a rat brain axolemma-enriched fraction did both. These results suggest that antibodies to GM1 do not have significant anti-myelin or anti-axon activity.

Combined features of myasthenia gravis and Eaton-Lambert syndrome: anti-ganglioside antibodies in serum

We studied 2 patients with Eaton-Lambert syndrome showing some features of myasthenia gravis. Among 9 different glycolipid antigens examined, serum titers of IgG antibodies to GT1b, GD1a, and sialylparagloboside were increased. Those antibodies may be involved in the pathogenesis of the presynaptic neuromuscular block that was presumed to be present in these patients.

Induction of experimental autoimmune encephalomyelitis in guinea pigs using myelin basic protein and myelin glycolipids

Strain 13 guinea pigs were immunized with galactocerebroside, asialo-GM1 (GA1) or GM4 ganglioside in association with myelin basic protein (MBP) in complete Freund's adjuvant (CFA) to produce experimental autoimmune encephalomyelitis (EAE). The clinical and pathological features, serum antibodies, and lipid compositions of affected brains and spinal cords were compared with those of guinea pigs immunized with MBP, in CFA, alone. Perivascular demyelination was seen in brains from all guinea pigs immunized with GA1/MBP. The incidence and degree of demyelination in this group were significantly higher than in the group immunized with only MBP. The onset of EAE was slightly, but significantly, retarded in groups of animals immunized with GM4/MBP and there was no detectable demyelination. Otherwise, no significant differences were detected between groups. Augmentation of EAE by myelin glycolipids may provide some important clues in understanding the mechanism of demyelinating diseases.

A calorimetric study of the thermotropic behaviour of mixtures of brain cerebrosides with other brain lipids

We have used a computer-controlled differential scanning calorimeter to determine the phases present in mixtures of the brain galactocerebrosides with other representative brain lipids. There are two types of brain galactocerebroside, those which possess an alpha-hydroxy substituent on the acyl chain (HFA) and those that do not (NFA). In the liquid crystalline state both cerebrosides were miscible with all the lipids studied, but in the gel state they were immiscible with cholesterol and the brain phosphatidylcholines. However, cholesterol mixtures in which the cholesterol mole fraction exceeded one third formed homogeneous metastable gel states on cooling from above the melting point of the cerebroside. Relaxation to the stable two phase state took place slowly over several hours. The solubilities of the galactocerebrosides in the other main brain sphingolipid, sphingomyelin, were much higher. Only in the case of the NFA galactocerebroside and at low mole fractions of sphingomyelin was immiscibility detected. Ternary mixtures of the two cerebrosides with sphingomyelin/cholesterol and phosphatidylcholine/cholesterol (PC/Chol) showed different miscibility characteristics. On cooling from 80 degrees C all mixtures formed homogeneous gel states. However, on standing the cerebrosides separated into discrete gel phases in all mixtures but one, that in which HFA galactocerebrosides were mixed with sphingomyelin and cholesterol. The cerebroside in the mixture with the composition closest to that of myelin, HFA/PC/Chol, melted at 38 degrees C. On scanning guinea pig CNS myelin which had been equilibrated at 5 degrees C a transition was detected with Tmax 33 degrees C. On the basis of comparison with the HFA/PC/Chol mixture we propose that the transition in myelin at this temperature is due to the melting of a galactocerebroside gel phase.

The properties of brain galactocerebroside monolayers

Using a Langmuir film balance we have compared the properties of films of the brain galactocerebrosides at 37 degrees C. There are two types of cerebroside in brain, those with an alpha-hydroxy substituent on the acyl chain (HFA) and those without (NFA). At equivalent pressures the areas of both cerebroside films are significantly less than the areas of films of the brain glycerolipids, the choline and ethanolamine phosphatides. The isotherm of NFA galactocerebrosides has two discontinuities, one at low and one at high film pressure, while the isotherm of HFA galactocerebrosides is a smooth curve at all film pressures. Below the high-pressure transition the area of the NFA film is significantly larger than the area of the HFA film. When compressed beyond the high-pressure transition there is a marked hysteresis between compression and expansion isotherms of the NFA galactocerebrosides. The pressures of both films continue to rise steeply when they are compressed into areas which are too small for them to exist as simple monolayers. We conclude that under compression cerebroside films form bilayer structures; that bilayer formation starts at low pressure and occurs progressively as the HFA cerebroside monolayer is compressed, but occurs more abruptly in the NFA cerebroside monolayer at the high-pressure-transition region of the isotherm. A study of pure cerebrosides with a single defined acyl chain shows that there is a correlation between the relative volumes of the hydrophobic and hydrophilic parts of the molecule and the ease of bilayer formation. The larger the relative volume of the hydrophilic group the more readily the cerebroside forms a bilayer film. Other brain lipids added to cerebroside monolayers have sharply differing effects on their areas. The areas of films containing cholesterol are less than the areas calculated by adding the areas of the pure components multiplied by their mole fractions. On the other hand, the area of phosphatidylcholine-containing films is much larger than calculated.

Antibody responses in chronic relapsing experimental allergic encephalomyelitis: correlation of serum demyelinating activity with antibody titre to the myelin/oligodendrocyte glycoprotein (MOG)

Antibody responses to the myelin/oligodendrocyte glycoprotein (MOG) and myelin basic protein (MBP) were determined in the sera of Hartley guinea pigs with chronic relapsing experimental allergic encephalomyelitis (CREAE) using an enzyme-linked immunoassay. The sera were also tested for in vivo demyelinating activity by infusion into the subarachnoid space of normal rats. In contrast to the MBP titres, the anti-MOG antibody titres showed good correlation with the in vivo demyelinating activity of the sera (r = 0.91, P less than 0.001). This result suggests that antibodies directed against MOG may be involved in the pathogenesis of demyelination in CREAE.

Natural seric anti-fatty acid antibodies in multiple sclerosis

Naturally occurring anti-oleic acid conjugate antibodies were detected in human sera using an adapted direct immunoenzymatic assay. They were present to a higher level in the sera of patients with multiple sclerosis in acute relapse compared to patients with other neurological diseases or healthy subjects and even patients with multiple sclerosis in progressive form.

Do human T-lymphotrophic viruses (HTLVs) and other enveloped viruses induce autoimmunity in multiple sclerosis?

A virally induced autoimmune reaction may be important in the pathogenesis of multiple sclerosis. The role that glycolipids and myelin basic protein presented to the virus may play in this process is considered. The most likely cells to be the source of autoantigens are neurons, myelin and oligodendrocytes. Viral infection of class II-expressing cells and association of the viral envelope autoantigens and the class II molecules could trigger an autoimmune reaction. It is suggested that for MS to develop following a virus infection the virus will need to cause expression of class II antigens on brain cells as well as fulfill the same role as an antigen presenting cell. The part which T-lymphotrophic viruses (HTLVs) and other enveloped viruses may play in this phenomenon is discussed.