Seiji Hitoshi

GM1b is a new member of antigen for serum antibody in Guillain-Barré syndrome.

Serum antibody from some patients with Guillain-Barre syndrome recognized an antigen of a minor component in human brain monosialoganglioside fraction. We purified that antigen, which migrated at a position slightly lower than that of GM1 on a thin-layer chromatogram (TLC), by using Iatrobeads column chromatography and preparative TLC. Structural analyses, including fast atom bombardment mass spectrometry, showed it to be GM1b. An enzyme-linked immunosorbent assay (ELISA) using purified GM1b showed that anti-GM1b antibody was present in 22 of 104 cases tested. No anti-GM1b antibody was present in the sera from control patients with other diseases or from the normal controls. Four sera recognized only GM1b among the 11 ganglioside antigens tested. The other 18 sera had antibodies to other antigens, most of which shared no terminal epitope with GM1b. Eight of nine sera samples with anti-GalNAc-GD1a antibody also had anti-GM1b antibody. Antibody to a minor monosialoganglioside, GM1b, was found to be a useful diagnostic marker for Guillain-Barre syndrome. Further study is needed to determine whether this antibody plays a role in the pathogenetic mechanism of the syndrome. NEUROLOGY 1996;47: 237-242

Monospecific anti-GD1b IgG is required to induce rabbit ataxic neuropathy

Of 22 rabbits sensitized with GD1b, 12 developed experimental sensory ataxic neuropathy. The affected rabbits had a higher level of serum IgG monospecific to GD1b than the unaffected ones. The GD1b‐positive neuronal cytoplasms of rabbit dorsal root ganglia had larger diameters than the negative ones. IgG antibody monospecific to GD1b may preferentially bind to large primary sensory neurons, causing sensory ataxic neuropathy. Ann Neurol 1999;45:400–403

Binding of antibodies against GM1 and GD1b in human peripheral nerve.

Human dorsal root ganglia (DRG), and ventral and dorsal roots were immunostained with rabbit antibodies recognizing GM1, GD1b, or both. Sera from rabbits immunized with GM1 or GD1b were separated in affinity columns into three fractions: Rab1, Rab2, and Rab3. Rab1 recognized only GM1, and Rab2 only GD1b; whereas Rab3 recognized both GM1 and GD1b, presumably by binding to the terminal galactosylβ1‐3N‐acetylgalactosaminyl residue. Rab2 and Rab3 immunostained most of the nerve cell bodies in the DRG and paranodal myelin of the ventral and dorsal roots, whereas Rab1 produced no significant immunostaining. These results show that GD1b is localized on the DRG neurons and the paranodal myelin of human peripheral nerve. These places may be the binding sites for anti‐GD1b antibodies, including those cross‐reactive with GM1, in the sera from patients with autoimmune neuropathies. GM1 may be dispersed in human DRG and dorsal and ventral roots.

Double mutations at codon 180 and codon 232 of the PRNP gene in an apparently sporadic case of Creutzfeldt-Jakob disease

Several polymorphisms of the prion protein gene are associated with the occurrence of familial Creutzfeldt-Jakob disease. We described a 84-year-old Japanese man with neuropathologically verified Creutzfeldt-Jakob disease of apparently sporadic type. His clinical presentation was atypical in point of a very late age at onset and absence of periodic synchronous discharge on electroencephalography. The patient carried double hitherto undescribed mutations of the prion protein gene; at codon 180 on one allele and at codon 232 on another. The mutation at codon 180 abolishes the Tth111I cutting site, which may be misunderstood to represent codon 178 mutation on routine restriction fragment length polymorphism study.

Molecular cloning and expression of a third type of rabbit GDP-L-fucose:beta-D-galactoside 2-alpha-L-fucosyltransferase.

Recent molecular investigation revealed that two closely related structural genes encode distinct GDP-L-fucose:β-D-galactoside 2-α-L-fucosyltransferases (α1,2-fucosyltransferases). Some human cancer cells or tissues may express an aberrant α1,2-fucosyltransferase other than H- and Secretor-type α1,2-fucosyltransferase. However, definite evidence of the existence of a third type of α1,2-fucosyltransferase has not been demonstrated. Here we report the molecular cloning of a third type of rabbit α1,2-fucosyltransferase (RFT-III) from a rabbit genomic DNA library. The DNA sequence included an open reading frame coding for 347 amino acids, and the deduced amino acid sequence of RFT-III showed 59 and 80% identity with those of the previously reported two types of rabbit α1,2-fucosyltransferase, RFT-I and RFT-II, respectively. COS-7 cells transfected with the RFT-III gene exhibited α1,2-fucosyltransferase activity toward phenyl-β-Gal as a substrate. Neuro2a (a murine neuroblastoma cell line) cells transfected with the RFT-III gene expressed fucosyl GM1 (type 3 H) but not Ulex europaeus agglutinin-1 lectin reactive antigens (type 2 H). Kinetic studies revealed that RFT-III exhibits higher affinity to types 1 (Galβ1, 3GlcNAc) and 3 (Galβ1, 3GalNAc) than to type 2 (Galβ1, 4GlcNAc) oligosaccharides, which suggests that RFT-III as well as RFT-II is a Secretor-type α1,2-fucosyltransferase. RFT-III was expressed in the adult gastrointestinal tract. The RFT-I, −II, and −III genes were assigned within 90 kilobases on pulsed field gel electrophoresis analysis. These results constitute direct evidence that, at least in one mammalian species, three active α1,2-fucosyltransferases exist.

Degeneration of rabbit sensory neurons induced by passive transfer of anti-GD1b antiserum

Systemic infusion of high-titer anti-GD1b antiserum to two rabbits pre-inoculated with keyhole limpet hemocyanin and Freunds complete adjuvant was performed. The two rabbits had low-titer anti-GD1b antibody in sera. Although no apparent clinical signs were observed, pathological examinations showed vacuolar degeneration with macrophage infiltration in a few axons in the dorsal columns of the spinal cords from the two rabbits. No such pathological changes were observed in the other two pre-inoculated rabbits infused with normal rabbit sera. Anti-GD1b antibody therefore may cause degeneration in rabbit sensory neurons with central axons extending to the dorsal column.

Rabbit experimental sensory ataxic neuropathy: anti-GD1b antibody-mediated trkC downregulation of dorsal root ganglia neurons.

We previously reported experimental sensory neuropathy in rabbit induced by the immunization of ganglioside GD1b. The major pathological change in diseased rabbits was degeneration of primary sensory neurons with central axons extending to the dorsal column of the spinal cord. The loss of primary sensory neurons that mediate proprioceptive sensation prompted us to investigate the expression of trkC in dorsal root ganglia (DRG) because this type of neuron is thought depend mainly on neurotrophin-3-mediated trkC signaling. Northern blotting analysis revealed markedly reduced expression of trkC in DRG of diseased rabbits in acute phase. This result together with the absence of lymphocytic infiltration in DRG of diseased rabbits at any stage suggests the anti-GD1b antibody-mediated downregulation of trkC expression could be one of the pathogenesis of this experimental sensory ataxic neuropathy.

Cerebellar ataxia and polyneuropathy in a patient with IgM M-protein specific to the Gal(β1-3) GalNAc epitope

A 79-year-old man with sensory dominant polyneuropathy, cerebellar ataxia, and palatal myoclonus had serum IgM M-protein that specifically bound to GM1, GD1b, and asialo-GM1. IgM with the same specificity was detected in his cerebrospinal fluid. Results of immunohistochemical studies showed specific binding of this monoclonal IgM to the cerebellar granular layer, dentate nucleus, inferior olive, and gray matter of the cerebrum and spinal cord. Monoclonal antibody GGR12, monospecific to GD1b, had an immunostaining distribution similar to that of the patients IgM M-protein. The binding of M-protein may be associated with the development of cerebellar ataxia and palatal myoclonus in this patient.

Binding of immunoglobulin G antibodies in Guillain-Barré syndrome sera to a mixture of GM1 and a phospholipid: possible clinical implications.

Anti‐GM1 immunoglobulin G (IgG) antibodies are frequently present in sera from patients with Guillain–Barré syndrome (GBS). A previous report on a patient who had a neuropathy with immunoglobulin M (IgM) M‐protein binding to a conformational epitope formed by phosphatidic acid (PA) and gangliosides prompted us to investigate the binding of IgG antibodies in GBS sera to a mixture of GM1 and PA (GM1/PA). Of 121 GBS patients, 32 had anti‐GM1 IgG antibodies. All 32 also had antibody activity against GM1/PA. Twenty‐five (78%) of 32 patients had greater activity against GM1/PA than against GM1 alone. Twelve patients who had no anti‐GM1 IgG antibodies had IgG antibody activity against GM1/PA. No GBS patient had IgG antibody against PA alone. In contrast, two rabbit anti‐GM1 antisera had greater activity against GM1 alone than against GM1/PA. IgG antibody with greater binding activity against a mixture of GM1 and a phospholipid than against GM1 alone may have an important role in the pathogenesis of GBS and has implications for diagnosis. Muscle Nerve 27: 302–306, 2003

PET analysis of a case of cerebrotendinous xanthomatosis presenting hemiparkinsonism

We describe a 34-year-old Japanese woman presenting gait difficulty and Achilles tendon swelling. The patient was diagnosed as having cerebrotendinous xanthomatosis (CTX) based on the high serum cholestanol level and diminished enzymatic activity of 27-hydroxylase of fibroblasts from her skin. Her clinical presentation was atypical regarding the presence of hemiparkinsonism and absence of apparent cataract, dementia, and cerebellar ataxia. Although MRI studies could not detect any abnormality in the basal ganglia or midbrain, PET analysis using [18F]-6-fluoro-L-dopa revealed reduced uptake of dopamine into the putamen, suggesting the impairment of presynaptic dopaminergic neurons.