Ganglioside GM1, a molecular target for immunological and toxic attacks: similarity of neuropathological lesions induced by ganglioside-antiserum and cholera toxin

Hyper-reflexia in Guillain-Barré syndrome: systematic review

Areflexia or hyporeflexia is a mandatory clinical criterion for the diagnosis of Guillain-Barré syndrome (GBS). A systematic review of the literature from 1 January 1993 to 30 August 2019 revealed 44 sufficiently detailed patients with GBS and hyper-reflexia, along with one we describe. 73.3% of patients were from Japan, 6.7% from the USA, 6.7% from India, 4.4% from Italy, 4.4% from Turkey, 2.2% from Switzerland and 2.2% from Slovenia, suggesting a considerable geographical variation. Hyper-reflexia was more frequently associated with antecedent diarrhoea (56%) than upper respiratory tract infection (22.2%) and the electrodiagnosis of acute motor axonal neuropathy (56%) than acute inflammatory demyelinating polyneuropathy (4.4%). Antiganglioside antibodies were positive in 89.7% of patients. Hyper-reflexia was generalised in 90.7% of patients and associated with reflex spread in half; it was present from the early progressive phase in 86.7% and disappeared in a few weeks or persisted until 18 months. Ankle clonus or Babinski signs were rarely reported (6.7%); spasticity never developed. 53.3% of patients could walk unaided at nadir, none needed mechanical ventilation or died. 92.9% of patients with limb weakness were able to walk unaided within 6 months. Electrophysiological studies showed high soleus maximal H-reflex amplitude to maximal compound muscle action potential amplitude ratio, suggestive of spinal motoneuron hyperexcitability, and increased central conduction time, suggestive of corticospinal tract involvement, although a structural damage was never demonstrated by MRI. Hyper-reflexia is not inconsistent with the GBS diagnosis and should not delay treatment. All GBS variants and subtypes can present with hyper-reflexia, and this eventuality should be mentioned in future diagnostic criteria for GBS.

Guillain-Barré syndrome associated with normal or exaggerated tendon reflexes

Areflexia is part one of the clinical criteria required to make a diagnosis of Guillain-Barré syndrome (GBS). The diagnostic criteria were stringently developed to exclude non-GBS cases but there have been reports of patients with GBS following Campylobacter jejuni enteritis with normal and exaggerated deep tendon reflexes (DTRs). The aim of this study is to expand the existing diagnostic criteria to preserved DTRs. From the cohort of patients referred for anti-ganglioside antibody testing from hospitals throughout Japan, 48 GBS patients presented with preserved DTR at admission. Thirty-two patients had normal or exaggerated DTR throughout the course of illness whereas in 16 patients the DTR became absent or diminished during the course of the illness. IgG antibodies against GM1, GM1b, GD1a, or GalNAc-GD1a were frequently present in either group (84 vs. 94%), suggesting a close relationship between the two groups. We then investigated the clinical and laboratory findings of 213 GBS patients from three hospital cohorts. In 23 patients, eight presented with normal tendon reflexes throughout the clinical course of the illness. Twelve showed hyperreflexia, with at least one of the jerks experienced even at nadir, and exaggerated reflexes returning to normal at recovery. The other three had hyperreflexia throughout the disease course. Compared to 190 GBS patients with reduced or absent DTR, the 23 DTR-preserved patients more frequently presented with pure motor limb weakness (87 vs. 47%, p = 0.00026), could walk 5 m independently at the nadir (70 vs. 33%, p = 0.0012), more frequently had antibodies against GM1, GM1b, GD1a, or GalNAc-GD1a (74 vs. 47%, p = 0.014) and were more commonly diagnosed with acute motor axonal neuropathy (65 vs. 34%, p = 0.0075) than with acute inflammatory demyelinating polyneuropathy (13 vs. 43%, p = 0.0011). This study demonstrated that DTRs could be normal or hyperexcitable during the entire clinical course in approximately 10% of GBS patients. This possibility should be added in the diagnostic criteria for GBS to avoid delays in diagnosis and effective treatment to these patients.

Endocytosis of glycosylphosphatidylinositol-anchored proteins

Glycosylphosphatidylinositol-anchored proteins (GPI-APs) represent an interesting amalgamation of the three basic kinds of cellular macromolecules viz. proteins, carbohydrates and lipids. An unusually hybrid moiety, the GPI-anchor is expressed in a diverse range of organisms from parasites to mammalian cells and serves to anchor a large number of functionally diverse proteins and has been the center of attention in scientific debate for some time now. Membrane organization of GPI-APs into laterally-organized cholesterol-sphingolipid ordered membrane domains or "rafts" and endocytosis of GPI-APs has been intensely debated. Inclusion into or exclusion from these membrane domains seems to be the critical factor in determining the endocytic mechanisms and intracellular destinations of GPI-APs. The intracellular signaling as well as endocytic trafficking of GPI-APs is critically dependent upon the cell surface organization of GPI-APs, and the associations with these lipid rafts play a vital role during these processes. The mechanism of endocytosis for GPI-APs may differ from other cellular endocytic pathways, such as those mediated by clathrin-coated pits (caveolae), and is necessary for unique biological functions. Numerous intracellular factors are involved in and regulate the endocytosis of GPI-APs, and these may be variably dependent on cell-type. The central focus of this article is to describe the significance of the endocytosis of GPI-APs on a multitude of biological processes, ranging from nutrient-uptake to more complex immune responses. Ultimately, a thorough elucidation of GPI-AP mediated signaling pathways and their regulatory elements will enhance our understanding of essential biological processes and benefit as components of disease intervention strategies.

Schwann cells are removed from the spinal cord after effecting recovery from paraplegia

Remyelination of the CNS is necessary to restore neural function in a number of demyelinating conditions. Schwann cells, the myelinating cells of the periphery, are candidates for this purpose because they have more robust regenerative properties than their central homologs, the oligodendrocytes. Although the ability of Schwann cells to remyelinate the CNS has been demonstrated, their capacity to enter the adult spinal cord in large numbers and effect functional recovery remains uncertain. We used cholera toxin B-subunit conjugated to saporin to demyelinate the rat lumbar spinal cord, remove macroglia, and produce paraplegia. After the removal of oligodendrocyte and astrocyte debris by invading macrophages, there was a spontaneous entry of Schwann cells into the spinal cord, along with axonal remyelination and concomitant functional recovery from paraplegia occurring within 75 d. The Schwann cells appeared to enter the dorsal funiculi via the dorsal root entry zone and the lateral funiculi via rootlets that had become adherent to the lateral spinal cord after the inflammation. In the following weeks, Schwann cell myelin surrounding central axons was progressively replaced by oligodendrocyte myelin without lapse in motor function. Our results show that endogenous Schwann cells can reverse a severe neurological deficit caused by CNS demyelination and enable later oligodendrocyte remyelination.

Hyperreflexia in Guillain-Barré syndrome: relation with acute motor axonal neuropathy and anti-GM1 antibody

OBJECTIVES

To investigate the incidence of hyperreflexia in patients with Guillain-Barré syndrome (GBS), and its relation with electrodiagnosis of acute motor axonal neuropathy (AMAN), antiganglioside GM1 antibody, and Campylobacter jejuni infection. It was reported that patients with AMAN in northern China often had hyperreflexia in the recovery phase.

METHODS

In 54 consecutive Japanese patients with GBS, sequential findings of tendon reflexes were reviewed. By electrodiagnostic criteria, patients were classified as having AMAN or acute inflammatory demyelinating polyneuropathy (AIDP). Anti-GM1 and anti-C jejuni antibodies were measured by enzyme linked immunosorbent assays.

RESULTS

Seven (13%) patients developed hyperreflexia with the spread of the myotatic reflex to other segments in the early recovery phase, one of whom already had hyperreflexia in the acute progressive phase. Of the seven patients, six had AMAN and all seven had anti-GM1 antibodies, whereas only two had anti-C jejuni antibodies. Hyperreflexia was more often found in patients with AMAN than AIDP (6/23 v 1/18, p=0. 002), and in patients with anti-GM1 antibodies than without them (7/26 v 0/28, p=0.01). Hyperreflexic patients had milder peak disabilities than patients without hyperreflexia (p=0.03). Increased motor neuron excitability in the hyperreflexic patients was supported by increased soleus H-reflex amplitudes and the appearance of H-reflexes in the small hand or foot muscles.

CONCLUSIONS

Hyperreflexia often occurs in patients with GBS especially with AMAN, anti-GM1 antibodies, and milder disease. Increased motor neuron excitability further characterises the subgroup of patients with GBS with AMAN and anti-GM1 antibodies.

Distinct immunoglobulin class and immunoglobulin G subclass patterns against ganglioside GQ1b in Miller Fisher syndrome following different types of infection

We studied serum antibodies against gangliosides GQ1b and GM1 in 13 patients with Miller Fisher syndrome (MFS) and in 18 patients with Guillain-Barré syndrome (GBS) with cranial nerve involvement. Anti-GQ1b titers were elevated in all patients with MFS cases (immunoglobulin G [IgG] > IgA, IgM), and in 8 of the 18 with GBS. Lower frequencies of increased anti-GM1 titers were observed in MFS patients (3 of 13), as well as in GBS patients (5 of 18). During the course of MFS, anti-GQ1b titers of all Ig classes decreased within 3 weeks after onset. By contrast, anti-GM1 titers (mainly IgM) transiently increased during the course of MFS in five of six patients, suggesting a nonspecific secondary immune response. In patients with MFS following respiratory infections, IgG was the major anti-GQ1b Ig class (six of six patients) and IgG3 was the major subclass (five of six). In contrast, four of five patients with MFS following gastrointestinal infections showed predominance of anti-GQ1b IgA or IgM over IgG and predominance of the IgG2 subclass; anti-GQ1b IgG (IgG3) prevailed in one patient only. These distinct Ig patterns strongly suggest that different infections may trigger different mechanisms of anti-GQ1b production, such as via T-cell-dependent as opposed to T-cell-independent pathways. Thus, the origin of antibodies against GQ1b in MFS may be determined by the type of infectious agent that precipitates the disease.

The pattern of antiganglioside antibody reactivities producing myelinated nerve conduction block in vitro

We studied the pattern of human antiganglioside antibody reactivities causing an acute conduction block in rat myelinated nerve fibers, using an in vitro preparation of the sciatic-tibial nerve. With the aid of complements, IgM antibodies reacting with the terminal disaccharide of galactose (beta1-3)N-acetylgalactosamine produced the block. These findings may help us to understand the mechanism in which the conduction block occurs in neuropathies associated with antiganglioside antibodies.

Ganglioside changes in brain in chronic relapsing experimental allergic encephalomyelitis induced in the Lewis rat

Chronic relapsing experimental allergic encephalomyelitis (CREAE) was induced in Lewis rats by inoculation with guinea-pig myelin and complete Freund's adjuvant followed by treatment with low-dose cyclosporin A. Rats were sacrificed at different phases of the disease (just before the onset of clinical signs, during the first clinical episode of CREAE and during the first recovery). Gangliosides were extracted from the brain, analysed after purification by HPTLC fractionation and quantified densitometrically. An increase of GM1, the main rat myelin ganglioside, and a decrease of GT1b, suggested to play a role in mediating the interactions between oligodendroglia and axons, were observed during the development of the CREAE. These findings indicating significant ganglioside changes in CREAE give further support to the concept concerning the involvement of gangliosides in autoimmune demyelination.

Association of IgM type anti-GM1 antibodies and muscle strength in chronic acquired demyelinating polyneuropathy

The pathogenetic role of anti-GM1 in chronic acquired demyelinating polyneuropathy (CADP) is uncertain. An association between antibodies and disease activity has not yet been established. In 8 patients with CADP followed longitudinally, anti-GM1 antibodies were monitored with a standardized enzyme-linked immunosorbent assay technique and muscle performance with isokinetic dynamometry. During a mean observation period of 24 months, strength improved in 6 of 8 patients by a median value of 54.5%, and anti-GM1 fell in all 6 patients; the reduction being 43%. In 2 patients, muscle performance deteriorated by 30 and 8%, whereas anti-GM1 titers increased by 10 and 9%, respectively. The relative change in anti-GM1 was inversely related to muscle performance. Clinical scoring of muscle performance according to the Medical Research Council scale failed to show an association with anti-GM1. It is concluded that anti-GM1 antibodies are closely related to disease activity, and that the close association indicates a role of anti-GM1 in the pathogenesis of CADP.

Ganglioside spinal cord changes in chronic relapsing experimental allergic encephalomyelitis induced in the Lewis rats

Chronic relapsing experimental allergic encephalomyelitis (CREAE) was induced in Lewis rats by inoculation with guinea-pig myelin and complete Freund's adjuvant followed by treatment with low-dose cyclosporin A. Rats were sacrified at different phases of the disease (just before the onset of clinical signs, during the first clinical episode of CREAE and during the first recovery). Gangliosides were extracted from the spinal cord, analysed after purification by two-dimensional chromatography and quantified densitometrically. An increase of GM 1, the main rat myelin ganglioside, and a decrease of GT1b, suggested to play a role in mediating the interactions between oligodendroglia and axons, were observed during the development of the CREAE. These findings indicating significant ganglioside changes in CREAE give further support to the concept concerning the involvement of gangliosides in autoimmune demyelination.

IgM anti-GM1 antibodies in the Guillain-Barré syndrome: a serological predictor of the clinical course

It has been suggested that antibodies against GM1 are involved in the pathogenesis of the Guillain-Barré syndrome (GBS). Recently, we have developed a standardized ELISA assay for anti-GM1 antibodies of IgM type well-suited for longitudinal patient studies. The relationship between serum antibodies against GM1 and Campylobacter jejuni was investigated in patients with GBS and in patients with C. jejuni infection. Patients with a short-lasting anti-GM1 elevation had a fast recovery, whereas patients with slow recovery had a long-lasting anti-GM1 elevation. A linear relationship was found between significant clinical recovery and the time until the anti-GM1 peak was halved (R = 0.9, p < 0.01). The absolute level of anti-GM1 did not predict the length of the recovery nor was the level of anti-GM1 related to the clinical disability at its nadir. Our data indicate that monitoring of the IgM anti-GM1 level can predict clinical recovery in GBS patients.

Antibodies to GM1 and Gal(beta 1-3)GalNAc at the nodes of Ranvier in human and experimental autoimmune neuropathy

Autoantibodies to Gal(beta 1-3)GalNAc epitopes on glycolipids and glycoproteins are associated with motor neuron disease and motor or sensorimotor neuropathy. These epitopes are ubiquitously distributed on cell surfaces. In the nervous system they are present on axons and myelin, specifically also at the nodes of Ranvier. Binding of GM1 antibodies to the nodal area may contribute to disease development in some of these conditions.

A somatically mutated human antiganglioside IgM antibody that induces experimental neuropathy in mice is encoded by the variable region heavy chain gene, V1-18

IgM paraproteins associated with autoimmune peripheral neuropathy and anti-Pr cold agglutinins react with sialic acid epitopes present on disialylated gangliosides including GD1b, GT1b, GQ1b, and GD3. A causal relationship between the paraprotein and the neuropathy has never been proven experimentally. From peripheral blood B cells of an affected patient, we have cloned a human hybridoma secreting an antidisialosyl IgM mAb, termed Ha1, that shows identical structural and functional characteristics to its serum counterpart. Variable region analysis shows Ha1 is encoded by the same VH1 family heavy chain gene, V1-18, as the only other known anti-Pr antibody sequence and is somatically mutated, suggesting that it [correction of is] arose in vivo in response to antigenic stimulation. In the rodent peripheral nervous system, Ha1 immunolocalizes to dorsal root ganglia, motor nerve terminals, muscle spindles, myelinated axons, and nodes of Ranvier. After intraperitoneal injection of affinity-purified antibody into mice for 10 d, electrophysiological recordings from the phrenic nerve-hemidiaphragm preparation demonstrated impairment of nerve excitability and a reduction in quantal release of neurotransmitter. These data unequivocally establish that an antidisialosyl antibody can exert pathophysiological effects on the peripheral nervous system and strongly support the view that the antibody contributes to the associated human disease.

Experimental immunization with Borrelia burgdorferi induces development of antibodies to gangliosides

Patients with neuroborreliosis produce antibodies, mostly of the immunoglobulin M (IgM) class, to gangliosides, particularly to those with Gal(beta 1-3)GalNac terminal sequences. Lewis rats were immunized with a nonpathogenic strain of Borrelia burgdorferi and with a chloroform-methanol extract (nonprotein) of this organism (CM) to determine whether antibodies to B. burgdorferi also recognized gangliosides. Rats were also immunized with asialo-GM1 to determine whether the elicited antibodies recognized antigens in B. burgdorferi. Rats immunized with B. burgdorferi produced low levels of IgM antibodies that cross-reacted with asialo-GM1 and GM1. Rats immunized with CM had marked IgM reactivity to asialo-GM1 and GM1. Immunization with asialo-GM1 resulted in antibodies that cross-reacted with B. burgdorferi antigens. Although antibodies to B. burgdorferi were of both the IgM and IgG classes, those to CM and to asialo-GM1 and GM1 were predominantly in the IgM fraction. Reactivity of the IgM antibodies decreased after adsorption with the heterologous and the homologous antigens, indicating bidirectional cross-reactivity between CM, asialo-GM1, and GM1 and that immunization with one produces antibodies to the other. There was no in vivo deposition of Ig in peripheral nerves, nor was there nerve pathology as a result of immunizations, but IgM antibodies to asialo-GM1 and CM recognized homologous antigens in the nodes of Ranvier of peripheral nerves from nonimmunized rats. This immunization model suggests that antibodies to gangliosides in Lyme disease have a microbial origin and are potentially relevant in pathogenesis.

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.

Chronic motor neuropathies: diagnosis, therapy, and pathogenesis

Pure motor neuropathy syndromes resemble amyotrophic lateral sclerosis variants with no upper motor neuron signs. Their identification is important, as, in contrast to amyotrophic lateral sclerosis, they are often immune mediated and treatable. Typically the immune-mediated motor neuropathy syndromes are distal and asymmetrical and progress slowly. The clinical features may help alert the clinician to the diagnosis, but other ancillary evidence such as abnormalities on electrophysiological testing and the presence of serum autoantibodies to neural antigens are helpful in making the diagnosis more secure. Electrophysiological abnormalities include not only motor conduction block but also other evidence of a demyelinative process such as prolonged distal latencies or F-wave abnormalities. High-titer anti-GM1 antibodies occur frequently but more specific patterns of reactivity may be especially helpful. Treatment of these motor neuropathy syndromes includes cyclophosphamide, which we use in combination with plasma exchange, and in some patients, human immune globulin. Clinical responses to therapy may occur within the first 2 to 4 months in patients with motor neuropathy syndromes with demyelinative features, but only become obvious 6 months or later after starting treatment in patients with predominantly axonal disorders.

Antibodies against GM1 ganglioside affect K+ and Na+ currents in isolated rat myelinated nerve fibers

High titers of anti-GM1 ganglioside antibodies (anti-GM1 antibodies) may be implicated in lower motor neuron disease. We studied the pathogenic role of anti-GM1 antibody using the petroleum jelly-gap voltage clamp technique on isolated single myelinated rat nerve fibers. Anti-GM1 antisera were obtained from rabbits immunized with GM1 ganglioside. Extracellularly applied anti-GM1 antisera without complement activity increased both the rate of rise and the amplitude of the K+ current elicited by step depolarization, with little effect on Na+ current. In the presence of active complement, however, anti-GM1 antibodies decreased the Na+ current, and caused a progressive increase of nonspecific leakage current. Neither complement alone nor complement-supplemented antisera from which anti-GM1 antibodies were depleted by affinity chromatography had any effect on ionic current. These observations indicate that anti-GM1 antibodies themselves can uncover K+ channels in the paranodal region, while anti-GM1 antibodies bound to the nodal membrane in the presence of complement may form antibody-complement complexes that block Na+ channels and disrupt the membrane at the node of Ranvier.

Antiglycolipid antibodies in peripheral neuropathy: fact or fiction?

Images

Pattern of nervous tissue immunostaining by human anti-glycolipid antibodies

Immunostaining of human, bovine and rodent unfixed nervous tissue sections was performed in order to characterize the structures recognized by anti-glycolipid antibodies. Four human sera from patients, two with M-IgM and motor neuron syndrome or motor neuropathy and two with motor neuropathy and polyclonal IgG antibody activity against gangliosides (GL; i.e. GM1, GD1b, GD1a), were utilized. Serum from a patient with sensory neuropathy and M-IgM immunoglobulins with antibody activity against sulfatide (SUL) was included in this series. This study shows that polyclonal and monoclonal anti-glycolipid antibodies give three different patterns of staining. The first is cholera toxin-like showing a more restricted neuronal pattern of staining. The second is peanut agglutinin-like, which includes the carbohydrate epitope shared by a group of glycoproteins in the gray and white matter. The third (anti-SUL) gives a preferential myelin staining. However, sera with anti-GM1 and anti-SUL antibodies recognize a number of closely situated determinants in the gray matter of the spinal cord and in the granule cells, while in peripheral nerves or in neuronal cells in culture their binding produces a different pattern (nodes of Ranvier for anti-GL; myelin for anti-SUL). These findings indicate that immunohistochemistry with anti-GL and anti-SUL antibodies may provide information regarding the glycolipid-bearing anatomical structures as target antigens and further substantiate the role of these molecules in the pathogenesis of autoimmune neurological disorders.

Gangliosides and bacterial toxins in Guillain-Barré syndrome

Autoimmune factors are strongly favoured as mediating Guillain-Barré syndrome (GBS); however, the precise mechanisms by which this occurs remain unknown. Microbial infections in a susceptible host resulting in an idiosyncratic immune response which cross-reacts with nerve constituents still remains the most plausible working hypothesis on which much current research is based. Considerable recent evidence indicates that this humoral immune response is at least in part directed to gangliosides. Interestingly, many bacterial toxins, including botulinum and tetanus neurotoxins, also bind to gangliosides and induce diseases with some similarities to GBS. This article discusses the evidence in favour of a pathogenic role for anti-ganglioside antibodies in GBS in the context of our knowledge of the biology of gangliosides and the factors that determine their immunogenicity.

Serum and CSF anti-GM1 antibodies in patients with Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy

High titers of antibodies directed against gangliosides, especially GM1, are found in the serum of patients with a variety of polyneuropathies, including those of the inflammatory type. We assayed anti-GM1 IgG and IgM levels in the serum and cerebrospinal fluid (CSF) of 23 patients with Guillain-Barré syndrome (GBS) and 10 with chronic inflammatory demyelinating polyneuropathy (CIDP) to investigate whether this immune response may also be localized within the intrathecal compartment and correlate with clinical parameters such as time interval since disease onset, disability score, preceding infectious episodes, and GM1 therapy. When compared to the control group, anti-GM1 IgG was increased in the serum of 39% of GBS and 10% of CIDP patients, whereas anti-GM1 IgM was elevated in 17% of GBS and none of the CIDP patients. In both patient groups, however, anti-GM1 antibody levels were more frequently elevated in CSF than paired sera: they belonged to the IgG class in 48% of GBS and 50% of CIDP patients, and to the IgM class in 48% of GBS and 55% of CIDP patients. In the GBS group, anti-GM1 IgM serum levels inversely correlated with time elapsed between sample collection and onset of disease (P < 0.05), whereas serum anti-GM1 IgG levels positively correlated with the loss of functional ability (P < 0.005). Increased anti-GM1 antibodies in GBS serum were not associated with clinical or serological evidence of infectious antecedents nor with previous GM1 treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of gangliosides on experimental allergic neuritis

The development of myelin-induced experimental allergic neuritis (EAN) in Lewis rats can be depressed and delayed by adding a ganglioside mixture (GM1, GD1a, GD1b, GT1b) to the immunization compound; however, gangliosides may enhance the induction of adjuvant arthritis. Antibodies against multiple gangliosides are produced in rats after immunization with gangliosides after addition of myelin, but only low titers can be detected in animals immunized with myelin and complete Freund's adjuvant alone. We conclude that this antibody production is not the result of peripheral nerve inflammation but depends rather from external applied gangliosides.

Different patterns of glycolipid antibody reactivity: lower motor neuron syndromes vs. immunization

High titers of serum antibodies against GM1 ganglioside occur frequently in patients with lower motor neuron (LMN) syndromes. We compared the specificities of the antiganglioside antibody reactivities in LMN patients with those arising after immunization of Lewis rats with several ganglioside containing preparations including purified GM1, human central nervous system (CNS) grey matter and white matter. Serums with high titers of anti-GM1 antibodies from patients with LMN syndrome usually showed limited cross-reactivity to other glycolipids but often bound to a Gal(beta 1-3)GalNAc-containing neoglycoprotein. In contrast, serums with anti-GM1 antibody arising after immunization showed broad cross-reactivity with other glycolipids but did not bind to the neoglycoprotein. We conclude that the serum patterns of antiganglioside antibody reactivity secondary to immunization with gangliosides and CNS components are different from the natural autoantibodies found in LMN patients. The antiganglioside antibodies seen in LMN patients are unlikely to be a result of autoreactivity to gangliosides after nervous tissue damage.

Antibodies to acidic glycolipids in Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy

Using an enzyme-linked immunosorbent assay and a thin-layer chromatography-immunostaining procedure, we detected serum antibodies against acidic glycolipids in 36 of 53 patients with Guillain-Barré syndrome (GBS) and 8 of 16 patients with chronic inflammatory demyelinating polyneuropathy (CIDP). Although we also found anti-acidic glycolipid antibodies in 4 of 13 patients with other neurological diseases; 2 of 10 patients with multiple sclerosis; 8 of 33 patients with inflammatory, infectious, allergic or autoimmune disorders and 3 of 32 healthy subjects, the levels of antibodies in these controls were much lower than in GBS patients. There were several patterns of reactivity of GBS sera including antibodies to LM1 and HexLM1, GM1 or GD1b or both, various other gangliosides, sulfated glycolipids, and as yet unidentified glycolipids. Sera from 30% of GBS patients had antibodies against two or more antigenically distinct acidic glycolipid antigens. Levels of anti-acidic glycolipid antibodies correlated with clinical symptoms in 9 of 11 GBS patients. While the increased incidence of antibodies to acidic glycolipids in patients with GBS (P less than 0.001) and CIDP (P less than 0.025) compared to controls could be an epiphenomenon, anti-acidic glycolipid antibodies may play a role in nerve injury in some GBS and CIDP patients.

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.

Experimental autoimmune neuropathy with anti-GM1 antibodies and immunoglobulin deposits at the nodes of Ranvier

Antibodies to GM1 or Gal(beta 1-3)GalNAc are associated with motor or sensorimotor neuropathy and with motor neuron disease. To investigate the role of these antibodies in the neurological disorder, rabbits were immunized with GM1 or with Gal(beta 1-3)GalNAc-BSA, and studied serologically, electrophysiologically and pathologically. Development of antibodies to the immunizing antigens was associated with a fall in the ratio of the amplitudes of the compound muscle action potential evoked by proximal versus distal stimulation of the sciatic nerve. Pathological studies revealed mild axonal degeneration and immunoglobulin deposits at the nodes of Ranvier in peripheral nerve, resembling those reported in a patient with motor neuropathy, motor conduction block and anti-GM1 antibodies. These studies provide evidence that anti-GM1 or anti-Gal(beta 1-3)GalNAc antibodies cause conduction abnormalities and indicate that the antibodies may exert their effect, in part, by binding at the nodes of Ranvier in peripheral nerve.

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.

Neuropathy and anti-GM1 antibodies

Increased titers of IgM antibodies that react with carbohydrate epitopes on GM1 are present in some patients with lower motor neuron disease, sensorimotor neuropathy, or motor neuropathy with or without conduction block. Therapeutic reduction of antibody concentrations can result in clinical improvement, suggesting that the antibodies may be pathogenic. The anti-GM1 antibodies react with carbohydrate epitopes, which are shared by several other glycolipids and glycoproteins in the central and peripheral nervous system. The antibodies might exert their effects at a number of sites, depending on the topographical distribution of the target antigens and on their accessibility. B-cells that express anti-GM1 antibodies are present at birth and are normally suppressed or rendered anergic. Under some circumstances, however, they might be activated to secrete autoantibodies that cause autoimmune neuropathy.

Anti-GM1 ganglioside antibodies with differing fine specificities in patients with multifocal motor neuropathy

Antibodies to gangliosides were detected in sera from three of 19 patients with chronic inflammatory polyneuropathy (CIP) by a thin-layer chromatogram overlay technique. All three of the patients fell into a clinical subset of the group that had multifocal motor neuropathy, and in all three patients the antibodies reacted with GM1 ganglioside. However, the fine specificities of the antibodies differed as demonstrated by cross-reactivity with different gangliosides in each of the three patients. The antibodies in patient 1 reacted with GM1, GD1b, and asialo-GM1 suggesting that the terminal Gal(beta 1-3)GalNAc moiety that is common to these three glycolipids is an important part of the epitope(s). This was confirmed by showing reactivity of the antibodies with Gal(beta 1-3)GalNAc conjugated to bovine serum albumin. Patient 2 had antibodies that did not react with GD1b, but cross-reacted with GM2 ganglioside suggesting that the epitope(s) involved the inner portion of the oligosaccharide moiety that is shared between GM1 and GM2. Patient 3 had antibodies that reacted with GM1 and asialo-GM1, but they did not cross-react with either GD1b or GM2. These results provide further evidence for a relationship between motor nerve syndromes and anti-GM1 antibodies and also suggest that GM1 could be a principal target antigen since other reactive gangliosides differed among the patients. However, the possible pathogenic effects of anti-GM1 antibodies on motor nerves remain to be established.

In vivo CNS demyelination mediated by anti-galactocerebroside antibody

The mechanism of antibody-mediated central nervous system (CNS) demyelination in vivo was studied using rabbit eyes. Injection of anti-galactocerebroside (Gal C) antiserum alone into the normal rabbit vitreous body induced demyelination in the epiretinal myelinated fibers. This activity of the antiserum disappeared after heat treatment at 56 degrees C for 30 min and was restored by supplement of normal fresh serum, suggesting the complement dependency of the activity. Heated anti-Gal C antiserum could induce demyelination, however, when macrophages were introduced by injecting lymphocyte supernatants together with antiserum. Electron microscopic study revealed penetration of macrophage process between the myelin lamella. These findings suggest that the cooperation of anti-Gal C antibody and macrophage can result in the antibody-dependent cell-mediated demyelination in the absence of complement. Because oligodendrocyte generally appeared normal, myelin, not oligodendrocyte is suspected to be the primary target by anti-Gal C antiserum. In contrast, neither anti-MBP nor anti-gangliosides antiserum had the in vivo-demyelinating activity. In CNS demyelination by anti-Gal C antibody, complement-mediated and macrophage-mediated mechanisms may cooperate in varying degrees.

Identification and characterization of gangliosides reacting with IgM paraproteins in three patients with neuropathy associated with biclonal gammopathy

IgM monoclonal antibodies from three patients with polyneuropathy associated with biclonal gammopathy reacted with monosialoganglioside GM1 on thin-layer chromatograms. An IgM paraprotein in one of the patients with a predominantly motor neuropathy also reacted strongly with the ganglioside GD1b and asialo-GM1. All three of these antigenic lipids have a Gal(beta 1-3)GalNAc moiety in common which would appear to be the antigenic determinant. However, this IgM also cross-reacted weakly with paragloboside which has an N-acetyllactosaminyl [Gal(beta 1-4)GlcNAc] terminal structure. The specificity of the other paraprotein in this patient is not known. The IgM paraproteins reacting with GM1 in both of the other patients exhibited different specificity because they did not react with GD1b and asialo-GM1, but reacted strongly with GM2 ganglioside. The data suggest that the epitope for both of these IgMs is in the GalNAc(beta 1-4)(NeuAc alpha 2-3)Gal(beta 1-4)Glc region of the gangliosides that is common to both GM2 and GM1. The second IgM paraproteins in both of these latter patients react with the myelin-associated glycoprotein (MAG) and two 3-sulfoglucuronyl glycolipids that share antigenic determinants with MAG.

A treatable multifocal motor neuropathy with antibodies to GM1 ganglioside

We report 2 patients with a treatable, immune-mediated motor polyneuropathy associated with antibodies to defined neural antigens. In these patients asymmetrical weakness developed in one arm and progressed over 2 to 3 years to involve the other arm, legs, and trunk. Both patients were initially diagnosed as having lower motor neuron forms of amyotrophic lateral sclerosis. However, repeated electrophysiological testing eventually showed multifocal conduction blocks in motor but not sensory fibers compatible with patchy selective demyelination. Serum testing by thin-layer chromatography and enzyme-linked immunosorbent assay revealed that both patients had high titers of antibody directed against GM1 and other gangliosides. Initial therapeutic trials of prednisone (100 mg daily for 4 to 6 months) and plasmapheresis were unsuccessful. Treatment with cyclophosphamide, however, was followed by marked improvement in strength in both patients.

Experimental allergic encephalomyelitis: the balance between encephalitogenic T lymphocytes and demyelinating antibodies determines size and structure of demyelinated lesions

The effect of a circulating monoclonal antibody recognizing an antigen located on the surface of myelin sheaths (myelin/oligodendroglia glycoprotein, MOG) on clinical and histopathological expression of experimental allergic encephalomyelitis (EAE) was tested in a model of EAE passively transferred by monospecific T lymphocytes. Intravenous injection of anti-MOG antibody at the onset of the disease massively augmented clinical impairment as well as primary demyelination. The structure of the CNS lesions depended on the balance between encephalitogenic T cells and anti-MOG antibody: when EAE was induced with high numbers of T cells, circulating anti-MOG antibody resulted in ubiquitous perivenous demyelination in the spinal cord and medulla oblongata. On the contrary, focal confluent demyelinated lesions were observed in animals injected with low numbers of T cells (even as few as 10(4] and anti-MOG antibody. Our studies, thus, indicate that the formation of inflammatory demyelinating lesions may be due to a synergistic action of cellular and humoral immune mechanisms.