Localization of sulfated glucuronyl glycolipids in human dorsal root and sympathetic ganglia

Structural and immunological characterization of sulphatides: relevance of sulphate moieties in Trypanosoma cruzi glycoconjugates

Sulphoglycosphingolipids, present on the surface of diverse cells, participate in the regulation of various cellular events. However, little is known about the structure and the role of sulphoglycosphingolipids in trypanosomatids. Herein, sulphated dihexosylceramide structures - composed mainly of sphingosine as the long chain base acylated with stearic acid - have been determined for the first time in Trypanosoma cruzi epimastigotes by UV-MALDI-TOF-MS analysis. Interestingly, inhibition ELISA assays using cruzipain as antigen and polyclonal rabbit antibodies specific for cruzipain, the major cysteine proteinase of T. cruzi, or for its C-terminal domain, have demonstrated (i) that sulphate epitopes are shared between cruzipain and sulphatides of T. cruzi, (ii) that cross-reactivity maps to the C-terminal domain and (iii) the existence of other antigenic determinants in the glycolipidic structures. These features provide evidence that sulphate groups are antigenic in sulphate-containing parasite glycoconjugates. Furthermore, IgG2 antibody levels inversely correlate with disease severity in chronic Chagas disease patients, suggesting that IgG2 antibodies specific for sulphated epitopes might be associated with protective immunity and might be considered as potential surrogates of the course of chronic Chagas disease.

The role of sulfoglucuronosyl glycosphingolipids in the pathogenesis of monoclonal IgM paraproteinemia and peripheral neuropathy

In IgM paraproteinemia and peripheral neuropathy, IgM M-protein secretion by B cells leads to a T helper cell response, suggesting that it is antibody-mediated autoimmune disease involving carbohydrate epitopes in myelin sheaths. An immune response against sulfoglucuronosyl glycosphingolipids (SGGLs) is presumed to participate in demyelination or axonal degeneration in the peripheral nervous system (PNS). SGGLs contain a 3-sulfoglucuronic acid residue that interacts with anti-myelin-associated glycoprotein (MAG) and the monoclonal antibody anti-HNK-1. Immunization of animals with sulfoglucuronosyl paragloboside (SGPG) induced anti-SGPG antibodies and sensory neuropathy, which closely resembles the human disease. These animal models might help to understand the disease mechanism and lead to more specific therapeutic strategies. In an in vitro study, destruction or malfunction of the blood-nerve barrier (BNB) was found, resulting in the leakage of circulating antibodies into the PNS parenchyma, which may be considered as the initial key step for development of disease.

Glycosphingolipid antigens in neural tumor cell lines and anti-glycosphingolipid antibodies in sera of patients with neural tumors

To characterize biomarkers in neural tumors, we analyzed the acidic lipid fractions of 13 neural tumor cell lines using enzyme-linked immunoabsorbent assay (ELISA) and high-performance thin-layer chromatography (HPTLC) immunostaining. Sulfated glucuronosyl glycosphingolipids (SGGLs) are cell surface molecules that are endowed with the Human Natural Killer-1 (HNK-1) carbohydrate epitope. These glycosphingolipids (GSLs) were expressed in all cell lines with concentrations ranging from 210 to 330 ng per 2 x 10(6) cells. Sulfoglucuronosyl paragloboside (SGPG) was the prominent species with lesser amounts of sulfoglucuronosyl lactosaminyl paragloboside (SGLPG) in these tumor cell lines as assessed by quantitative HPTLC immunostaining. Among the gangliosides surveyed, GD3 and 9-O-acetylated GD3 (OAc-GD3) were expressed in all tumor cell lines. In contrast, fucosyl-GM1 was not found to restrict to small cell lung carcinoma cells. In addition, we have analyzed serum antibody titers against SGPG, GD3, and OAc-GD3 in patients with neural tumors by ELISA and HPTLC immunostaining. All sera had high titers of antibodies of the IgM isotype against SGPG (titers over 1:3,200), especially in tumors such as meningiomas, germinomas, orbital tumors, glioblastomas, medulloblastomas, and subependymomas. Serum in a patient with subependymomas also had a high anti-SGGL antibody titer of the IgG and IgA types (titers over 12,800). The titer of anti-GD3 antibody was also elevated in patients with subependymomas and medulloblastomas; the latter cases also had a high titer of antibody against OAc-GD3. Our data indicate that certain GSL antigens, especially SGGLs, GD3, and OAc-GD3, are expressed in neural tumor cells and may be considered as tumor-associated antigens that represent important biomarkers for neural tumors. Furthermore, antibody titers in sera of patients with these tumors may be of diagnostic value for monitoring the presence of tumor cells and tumor progression.

Induction of experimental ataxic sensory neuronopathy in cats by immunization with purified SGPG

IgM paraproteins in about 50% of the patients with neuropathy associated with IgM gammopathy react with carbohydrate moieties in myelin-associated glycoprotein (MAG) and in sulfated glucuronic glycolipids (SGGLs) in human peripheral nerves. However, the role of anti-MAG/SGGL antibodies in the pathogenesis of neuropathy remains unclear. In order to induce an animal model of neuropathy associated with anti-MAG/SGGL antibodies, cats were immunized with sulfoglucuronyl paragloboside (SGPG). All four cats immunized with SGPG developed clinical signs of sensory neuronopathy within 11 months after initial immunization, characterized by unsteadiness, falling, hind limb weakness and ataxia. In two cats the ataxia and hind limb paralysis were so severe that the animals had to be euthanized. Pathological examination revealed sensory ganglionitis with inflammatory infiltrates in the dorsal root ganglia. No overt signs of pathology were noted in the examined roots or nerves. High titer anti-SGPG/MAG antibodies were detected in all 4 cats immunized with SGPG but not in 3 control cats. Our data demonstrate that immunization of cats with SGPG induced anti-SGPG antibodies and sensory neuronopathy clinically resembling the sensory ataxia of patients with monoclonal IgM anti-MAG/SGPG antibodies. This study suggests that these anti-MAG/SGPG antibodies play a role in the pathogenesis of this neuropathy.

Variability in immunohistochemistries of IgM M-proteins binding to sulfated glucuronyl paragloboside

Serum IgMs from 4 of 12 patients with polyneuropathy and IgM M-proteins that bind to sulfated glucuronyl paragloboside (SGPG) strongly immunostained the human peripheral nerve myelin (group A), whereas those from the other eight patients strongly immunostained the cytoplasm of the Schwann cells surrounding the myelin sheath with only weak staining of the myelin (group B). Strong immunostaining of peripheral myelin by IgMs from group A patients may be due to the strong cross-reactivities against P0 and peripheral myelin protein-22 (PMP-22), which are localized in compact myelin. Only three patients (all in group B) showed some response to the immunotherapies. Weak reactivities to P0 and and PMP-22 might indicate the possibility of improvement after the immunotherapies.

Sensory nerve conduction deficit in experimental monoclonal gammopathy of undetermined significance (MGUS) neuropathy

An emerging body of evidence from in vitro studies and in vivo animal models supports a pathogenic role of antibodies in the development of peripheral neuropathy associated with monoclonal gammopathy of undetermined significance (MGUS). Although the assessment of motor and sensory nerve fiber function is of clinical importance, it is seldom applied experimentally. We describe the application of an electrophysiologic method for the evaluation of motor and sensory nerve fiber function using an experimental model of MGUS neuropathy. Supramaximal stimulation of the tibial nerve elicited an early motor response (M-wave, 1.7 +/- 0.1 ms, n = 10) and a late sensory (H-reflex, 7.8 +/- 0.1 ms, n = 10) response that was recorded from the hind foot of anesthetized rats. Intraneural injection of serum antibodies from a MGUS patient with sensorimotor polyneuropathy, but not from an age-matched control subject, produced a marked attenuation of the H-reflex (P < 0.01, n = 10) without affecting the M-wave. Light and electron microscopy of affected nerve showed myelinoaxonal degeneration with sparing of the smaller unmyelinated nerve fibers. The combined electrophysiologic and morphologic findings presented in this study are consistent with a selective sensory conduction deficit in MGUS neuropathy. Selective injury of afferent nerve fibers by this patient's serum antibodies may result from reactivity to neural antigens uniquely expressed by sensory neurons.

Elevation of serum soluble E-selectin and antisulfoglucuronyl paragloboside antibodies in amyotrophic lateral sclerosis

Immunological abnormality is often found in amyotrophic lateral sclerosis (ALS). Antibodies to sulfoglucuronyl paragloboside (SGPG) were reported in ALS, although the pathogenetic significance of the antibodies is still unknown. We have already demonstrated that SGPG, a unique glycolipid, is present in both peripheral nerve and vascular endothelial cells. To investigate whether serum anti-SGPG antibodies would participate in activation and/or injury of endothelial cells in ALS, we examined serum anti-SGPG antibodies in association with serum soluble E- and P-selectins, which are markers of activated endothelial cells, in 25 patients with ALS and 14 age-matched patients with other neurological diseases (ONDs) using the microtiter-ELISA method. Seven out of 25 ALS patients had anti-SGPG antibodies. Levels of sE-selectin were significantly higher in patients with ALS (48.5 +/- 23.4 ng/ml) compared with ONDs (24.0 +/- 11.8 ng/ml) (P < 0.005). Four out of seven ALS patients with anti-SGPG antibodies had concomitantly high sE-selectin levels. The mean sE-selectin levels were higher in patients with anti-SGPG antibodies (61.9 +/- 25.2 ng/ml) than in those without anti-SGPG antibodies (43.3 +/- 21.1 ng/ml). Anti-SGPG antibodies may take part in the activation and/or injury of endothelial cells. The increased expression of E-selectin may be related to an immunological process in some ALS patients.

Heterogeneity of antibody specificity in Taiwanese patients with polyneuropathy and IgM paraproteinemia

About half of the Caucasian patients with chronic polyneuropathy and IgM paraproteinemia show serum anti-myelin-associated glycoprotein (MAG) and anti-sulfoglucuronosyl glycosphingolipid (SGGLs) activities. These antibody activities have been demonstrated to react with a carbohydrate epitope known as the HNK-1 or sulfoglucuronic acid (SGA) epitope. However, in Asian populations the occurrence of serum anti-SGA activities has been reported to be relatively rare. We investigated 5 cases of chronic polyneuropathy with IgM paraproteinemia from Taiwan and found that 3 of them had high-titer serum anti-SGA (SGGL/MAG) antibody activities. The clinical symptoms of these 3 patients were consistent with sensory dominant polyneuropathy with a severer involvement of the lower limbs than of the upper limbs. Electromyography and nerve conduction studies revealed severe sensory nerve involvement (no response in 3 cases) and moderate slowing of motor conduction velocity (MCV) without conduction block. The decrease in MCV correlated well with anti-SGA antibody titer (less than 30 m/s with the titration of 1:12, 800, normal 55-60 m/s). Pathological findings showed active demyelinating polyneuropathy with myelin ovoid and myelinated fiber loss. Our data suggest that anti-SGGL antibody activities may not be very rare among Asian populations. Additionally, there seems an intriguing possibility that the titer of this antibody correlates with the severity of peripheral nerve involvement in patients of demyelinating polyneuropathy with IgM paraproteinemia.

The role of glycosphingolipids in neurological disorders. Mechanisms of immune action

Specific criteria that are required for understanding the significance of glycosphingolipid (GSL) antibodies, as well as mechanisms that may underlie the immunopathogenesis of these disorders, are proposed. These criteria are illustrated by describing the role of a unique family of acidic GSLs, the sulfated glucuronosyl glycolipids (SGGLs), in the pathogenic mechanisms of peripheral neuropathy with IgM paraproteinemia. High anti-SGGL antibody titers are detected in patients suffering from this disorder. It is demonstrated that SGGLs, which possess a common carbohydrate epitope with myelin-associated glycoprotein (MAG), several low-molecular-weight glycoproteins in the PNS, and a number of cell adhesion molecules, are potential target antigens for the neuropathy. Evidence is provided that sensitization of laboratory animals with pure SGGLs elicits experimental peripheral neuropathies that exhibit remarkable similarities with respect to antibody specificity, and electrophysiological and pathological features to the human conditions. By intraneural injection of antibodies into the sciatic nerve of rats, it is demonstrated that pathological changes consisting of demyelination and axonal degeneration are mediated by an antibody- and complement-dependent process. To elucidate the mechanisms of antibody penetration from circulation into the endoneurial space, it is further shown that brain microvascular endothelial cells express SGGLs. Moreover it has been found that inflammatory cytokines are capable of upregulating the expression of SGGLs on the endothelial cell surface, resulting in a greater attachment of leukocytes. This latter observation suggests that SGGLs may also participate in cell-mediated responses in certain inflammatory neurological disorders.

Sulfoglucuronosyl glycolipids as putative antigens for autoimmune inner ear disease

Autoimmune inner ear disease is diagnosed based on clinical history of fluctuating but progressive sensorineural hearing loss (SNHL) with or without vestibular symptoms occurring over weeks to months. An initial response to steroids or immunosuppressive drugs usually reverses the hearing loss. In search of specific diagnostic and therapeutic markers for autoimmune inner ear diseases, we investigated serum anti-glycolipid antibody activities in these patients by two different methods, HPTLC-immunoblotting and ELISA. We found that 37 out of 74 patients of clinically diagnosed autoimmune inner ear disease (30 of sensorineural hearing loss (SNHL) (group I), 14 of vestibular symptoms only (group II), 30 of Menieres symptoms (with both hearing loss and vestibular symptoms) (group III)) showed positive anti-sulfoglucuronosyl lactosaminyl paragloboside (SGLPG) antibody titers (p < 0.001). On the other hand, anti-sulfoglucuronosyl paragloboside (SGPG) titers were not elevated in these conditions. In contrast, only 3 out of 56 pathological control and 2 out of 28 healthy volunteers had measurable anti-SGLPG antibody titers. We further analyzed the localization of SGLPG in the auditory pathway and found that the antigens existed exclusively in inner ear and the eighth nerve, but not in pons, cerebellum, nor cerebrum. We conclude that the anti-SGLPG antibody represents a novel diagnostic marker for autoimmune inner ear disease and may participate in the pathogenesis of this disease.

Morphological changes at paranodes in IgM paraproteinaemic neuropathy

The paranode is one of a number of sites of a specific myelin sheath abnormality found in cases of IgM paraproteinaemic neuropathy. The gammopathy may be malignant or, more frequently, benign, and is often associated with a predominantly demyelinating neuropathy. The circulating paraprotein IgM antibody, usually with kappa light chains, was found in many cases to recognise an antigenic determinant in myelin, identified as myelin-associated glycoprotein (MAG). Other glycoconjugates expressed by Schwann cells may also be recognised by the antibody. MAG is localized to regions of the myelin sheath in which the membranes are uncompacted. The paranode is one such region, and there is evidence that IgM is deposited specifically on the membranes of the terminal loops of the myelin sheath in addition to other MAG-associated regions of the sheath. In many cases the presence of the paraprotein appears not to otherwise affect paranodal organization; in a few it is associated with changes to the termination of the loops on the axolemma and to the associated Schwann cell cytoplasm. These findings do not provide unambiguous evidence that binding of anti-MAG IgM antibodies at the paranode is a direct cause of demyelination. Whilst localization of the paraprotein closely matches that of MAG, proof is still lacking that the relevant antigen is MAG itself.

Generation and characterization of anti-sulfoglucuronosyl paragloboside monoclonal antibody NGR50 and its immunoreactivity with peripheral nerve

Sulfoglucuronosyl paragloboside (SGPG) is a member of the sulfated glucuronic acid-containing glycolipid (SGGL) family found primarily in peripheral nerves. These glycolipids contain the HNK-1 carbohydrate epitope and are recognized by monoclonal IgM from patients with chronic demyelinating neuropathy and paraproteinemia. Recent studies indicate that SGGLs may serve as ligands for selectins, amphoterin, and laminin, suggesting that these glycolipids may play an important role in cellular adhesion. To elucidate the biological function of these glycolipids, we produced a murine monoclonal antibody (mAb) and studied its antigenic specificity. Using an enzyme-linked immunosorbent assay (ELISA), we found that the mAb designated as NGR50 belonged to the IgG2a subclass, and that the minimal titer (2 SD above the mean optical density value of control) of this mAb was 1:640, with 20 ng of purified SGPG as the antigen. Thin-layer chromatography (TLC) immunoblotting revealed that this mAb reacted specifically with SGPG and sulfoglucuronosyl lactosaminyl paragloboside (SGLPG), which is a structural analogue of the former, but not with other glycolipids. Desulfated derivates of SGPG and SGLPG did not react with mAb NGR50. Western blot analysis showed crossreactivity with human myelin-associated glycoprotein (MAG), but not with rat MAG or rat glycoprotein P0. Unlike anti-HNK-1 monoclonal antibody, however, NGR50 reacted only weakly with several proteins in the 20-30-kD regions, including human P0, suggesting that mAb50 has a different fine specificity as an anti-HNK-1 antibody. Immunocytochemical study of rat sciatic nerve using mAb NGR50 revealed positive staining at the outer surface of the myelin sheath and Schwann cells, as well as in the intervening connective tissues. Faint staining was also visible at the axolemmal-myelin interface; however, compact myelin was not stained.

T-cell-mediated ganglionitis associated with acute sensory neuronopathy

A 67-year-old man presented with acute painful sensory loss, areflexia, ataxia, urinary retention, and severe constipation and became unable to walk within 2 weeks. He died suddenly 5 weeks after the onset of symptoms. Autopsy revealed widespread inflammation of sensory and autonomic ganglia with immunocytochemical evidence of a CD8+ T cell-mediated cytotoxic attack against ganglion neurons. This observation suggests a novel pathogenetic mechanism of immune-mediated human ganglion cell damage comparable to mechanisms operating in polymyositis.

Sensitization of Lewis rats with sulfoglucuronosyl paragloboside: electrophysiological and immunological studies of an animal model of peripheral neuropathy

Antibodies against sulfoglucuronosyl glycosphingolipids (SGGLs) are known to be present in sera of patients with chronic polyneuropathy associated with IgM paraproteinemia. We recently studied rats sensitized with sulfoglucuronosyl paragloboside (SGPG), a major SGGL species, emulsified with keyhold limpet hemocyanin and Freund's adjuvant. The titer of the IgM class antibodies against SGPG increased up to 1:1,600, while that of the IgG class increased up to 1:800 2 weeks after sensitization. The antibodies showed a high degree of antigenic specificity; no cross-reactivity with other brain glycolipids could be detected. They, however, reacted with human myelin-associated glycoprotein (MAG) by Western blot analysis, but not with rat MAG. These animal models showed minor but clear clinical signs of neuropathy, consisting of mild tail muscle tone loss and walking disabilities. Electrophysiological examination of the sciatic nerves revealed nerve conduction abnormalities which consisted of conduction block and mild decrease in conduction velocity. Thus, our results support the concept that anti-SGPG antibodies may play an important pathogenetic role in this type of chronic neuropathy.

Antibody to silicone and native macromolecules in women with silicone breast implants

Silicone implants have been associated with the development of multiple organ system abnormalities, including rheumatic disorders, nervous system, pulmonary dysfunction associated with autoantibodies and abnormalities of cellular immunity. In this regards a number of case reports and series of articles have been described. We hypothesized that an immune reaction to silicone breast implants would include the host reactivity against silicone and the macromolecules within the microenvironment of the implant, and these autoantibodies may react with other tissue antigens far from the site of the implant. To test this hypothesis 520 Symptomatic women with Silicone Implants which have developed Silicone related Immunological disorders and have typically complained of breast pain, Myalgia-Arthralgia, fatigue, or generalized pain, were examined by their physician. Blood samples were obtained and examined for the presence of Silicone antibodies, Myelin Basic Protein and human serum albumin antibodies. These samples were then compared to 520 matched controls without implants. At least at the level of two standard deviation silicone specific antibodies, IgG, IgA IgM, IgE and IgG+IgA+IgM antibodies were detected above the mean of normal controls. When these antibodies were classified based on the specialty of the examining physician, the % of patients with Silicone Antibodies were varied; general practice 51.6, Rheumatology 58.7, and Plastic Surgery 83.3, which may relate to the severeness of the disease. Being that a large % of patients demonstrated very high levels of Myelin Basic Protein Antibodies, possible cross reactive antibodies were sought. However, absorption of highly positive sera for Silicone Antibodies with MBP did not change the levels of Silicone Antibodies. On the other hand, Silicone-HSA was able to reduce the antibody values significantly. This reduction in antibody levels by Silicone is the best indication for the specificity of these antibodies. Moreover when data for silicone antibodies and MBP antibodies was analyzed in patients some with high and others with medium or low levels of silicone antibodies, MBP antibodies did not correspond to the silicone antibody levels. Similarly human serum albumin antibodies which was significantly higher in patients with silicone implants did not correlate with levels of silicone antibodies. These results indicate that immune reaction to silicone and different tissue antigens do occur and they are initiated through different mechanisms. And since predominant antibody class against silicone, MBP and HSA was IgM, clonal activation of IgM is possible which certainly warrants further investigation.

Expression and biological functions of sulfoglucuronyl glycolipids (SGGLs) in the nervous system--a review

Sulfoglucuronyl carbohydrate linked to neolactotetraose reacts with HNK-1 antibody. The HNK-1 carbohydrate epitope is found in two major glycolipids, several glycoproteins and in some proteoglycans of the nervous system. Most of the HNK-1 reactive glycoproteins so far identified are neural cell adhesion molecules and/or are involved in cell-cell interactions. HNK-1 carbohydrate is highly immunogenic. Several HNK-1-like antibodies, including IgM of some patients with plasma cell abnormalities and having peripheral neuropathy, have been described. This article summarizes published work mainly on sulfoglucuronyl glycolipids, SGGLs and covers: structural requirements of the carbohydrate epitope for binding to HNK-1 and human antibodies, expression of the lipids in various neural areas, stage and region specific developmental expression in CNS and PNS, immunocytochemical localization, loss of expression in Purkinje cell abnormality murine mutations, biosynthetic regulation of expression by a single enzyme N-acetylglucosaminyl transferase, identification of receptor-like carbohydrate binding neural proteins (lectins), and perceived role of the carbohydrate in physiological functions. The latter includes role in: pathogenesis of certain peripheral neuropathies, in migration of neural crest cells, as a ligand in cell-cell adhesion/interaction and as a promoter of neurite outgrowth for motor neurons. Multiple expression of HNK-1 carbohydrate in several molecules and in various neural cell types at specific stages of nervous system development has puzzled investigators as to its specific biological function, but this may also suggest its importance in multiple systems during cell differentiation and migration processes.

Glycosphingolipid antigens in cultured bovine brain microvascular endothelial cells: sulfoglucuronosyl paragloboside as a target of monoclonal IgM in demyelinative neuropathy [corrected]

Since a number of anti-glycosphingolipid (GSL) antibody activities have been demonstrated in patients with various neurological disorders, the presence of common antigens between brain microvascular endothelial cells (BMECs) and the nervous tissues presents a potential mechanism for the penetration of macromolecules from the circulation to the nervous system parenchyma. We first investigated GSL composition of cultured bovine BMECs. Bovine BMECs express GM3(NeuAc) and GM3(NeuGc) as the major gangliosides, and GM1, GD1a, GD1b, GT1b, as well as sialyl paragloboside and sialyl lactosaminylparagloboside as the minor species. Sulfoglucuronosyl paragloboside was also found to be a component of the BMEC acidic GSL fraction, but its concentration was lower in older cultures. On the other hand, the amounts of neutral GSLs were extremely low, consisting primarily of glucosylceramide. In addition, we analyzed the effect of anti-SGPG IgM antibody obtained from a patient of demyelinative polyneuropathy with macroglobulinemia against cultured BMECs. Permeability studies utilizing cocultured BMEC monolayers and rat astrocytes revealed that the antibody facilitated the leakage of [carboxy-14C]-inulin and 125I-labeled human IgM through BMEC monolayers. A direct cytotoxicity of this antibody against BMECs was also shown by a leakage study using [51Cr]-incorporated BMECs. This cytotoxicity depended on the concentration of the IgM antibody, and was almost completely blocked by preincubation with the pure antigen, sulfoglucuronosyl paragloboside. Our present study strongly supports the concept that immunological insults against BMECs induce the destruction or malfunction of the blood-nerve barrier, resulting in the penetration of the immunoglobulin molecule to attach peripheral nerve parenchyma.

Subcellular Distribution of Sulfated Glucuronyl Glycolipids in Human Peripheral Motor and Sensory Nerves

Sulfated glucuronyl glycolipids (SGGL) have been implicated as important target antigens in patients with demyelinating polyneuropathy and IgM paraproteinemia. Sulfated glucuronyl paragloboside (SGPG), a major species of SGGL, was identified in the subcellular fractions of human peripheral motor and sensory nerves using a simple and quantitative method. SGPG was found to be concentrated in the myelin-enriched fractions of both motor and sensory nerves (1.3 +/- 0.3 and 1.5 +/- 0.4 &mgr;g/mg protein, respectively), whereas its concentration was 0.9 +/- 0.2 and 1.8 +/- 0.6 &mgr;g/mg protein in the axolemma-enriched fractions of motor and sensory nerves, respectively. Our finding that SGPG is more abundant in the human sensory nerve axolemma-enriched fraction may account for the clinical and pathological observations that the lesions are more heavily concentrated in the sensory nerve than in other parts of the nerve tissues in this disorder. Copyright 1994 S. Karger AG, Basel

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.

Antibodies to sulfatide and to chondroitin sulfate C in patients with chronic sensory neuropathy

Sera from eight of 25 patients with chronic sensory neuropathy had high titers of antibodies to sulfatide and chondroitin sulfate C or both. Preclearing of patients' sera with either sulfatide or chondroitin sulfate C revealed that in four patients the antisulfatide antibodies crossreacted with chondroitin sulfate C. By indirect immunohistochemistry sera reactive to sulfatide only had a different staining pattern from those reactive to both sulfatide and chondroitin sulfate C. By direct immunohistochemistry we found immunoglobulins bound to nerve fibers only in patients with serum antibodies against both sulfatide and chondroitin sulfate C. Our study provides evidence that antibodies to sulfatide and to chondroitin sulfate C differ in their fine specificity and are present in 30% of patients with chronic sensory neuropathy.

Anti-sulfatide antibodies in neurological disease: binding to rat dorsal root ganglia neurons

Increased titers of anti-sulfatide antibodies were detected by ELISA in 5 of 200 patients and control subjects. All 5 patients had sensory impairment; 4 had neuropathy, and one had multiple sclerosis. Of the patients with neuropathy, 2 had a clinical syndrome of small fiber sensory neuropathy with normal electrophysiological or nerve biopsy studies, 1 had a sensorimotor axonal neuropathy associated with IgM monoclonal gammopathy, and 1 had sensorimotor neuropathy with multifocal motor conduction block and anti-GM1 antibodies. The anti-sulfatide antibodies bound to the surface of unfixed rat dorsal root ganglia neurons and human neuroblastoma cells, and to fixed sections of central and peripheral myelin. No binding was detected following intraneural injection into rat sciatic nerves. Pre-absorption with sulfatide but not with galactocerebroside eliminated the tissue binding activity. These findings indicate that increased titers of anti-sulfatide antibodies are found in patients with sensory impairment but are not restricted to a particular neurological syndrome or type of neuropathy. The significance of anti-sulfatide antibodies is uncertain although sulfatide on dorsal root ganglia neurons may be a target antigen.

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.

Preliminary studies on sensitization of Lewis rats with sulfated glucuronyl paragloboside

A large number of patients with peripheral neuropathy and IgM paraproteinemia have IgM monoclonal antibodies which recognize a carbohydrate determinant shared by myelin-associated glycoprotein (MAG) and sulfated glucuronyl glycolipids (SGGLs). There is considerable evidence that these IgM monoclonal antibodies are responsible for demyelination in this disorder. To study the pathogenic role of SGGLs in this type of neuropathy, we sensitized Lewis rats with sulfated glucuronyl paragloboside (SGPG), a major SGGL. Fifty percent of the animals (8/16) developed neurological symptoms such as mild to moderate distal tail tone loss, with or without abnormal posture, along with development of anti-SGPG antibodies. These antibodies reacted with SGGLs, but not with rat MAG. Morphological studies showed: (1) axonal change in the lateral aspects of the dorsal columns in the spinal cord; and (2) damage to the endothelial cells in the spinal cord which suggested a breakdown of the blood-brain barrier. There was no obvious change in the peripheral nerve. Since no marked cellular infiltration was detected in these lesions, the clinicopathological findings observed could be induced by humoral mechanism, most likely anti-SGPG antibodies.