Analysis of humoral immune responses to LM1 ganglioside in guinea pigs.

Guillain-Barré syndrome (GBS) is an autoimmune-mediated disease triggered by a preceding infection. A substantial body of evidence implicates antibodies to various gangliosides in subtypes of GBS. A significant proportion of patients with acute demyelinating subset of GBS have IgG antibodies against peripheral nervous system myelin specific neolactogangliosides such as LM1 and Hex-LM1. Although anti-neolactoganglioside antibodies in GBS were described more than two decades ago, their pathogenic role in neuropathy remains unknown due to the lack of suitable experimental models. In this study, we immunized ten guinea pigs with purified LM1 ganglioside mixed with keyhole limpet hemocyanin (KLH) and emulsified in complete Freund's adjuvant (CFA). Control guinea pigs were injected with KLH emulsified in CFA only. The animals were bled every four week intervals. The animals were boosted 3 times every four weeks. Experiments were terminated four months after initial immunization. Nine of 10 guinea pigs immunized with LM1 exhibited antibody responses to LM1. Anti-LM1 IgG titers in nine guinea pigs ranged from 1:400 to 1:12,800 at 16-weeks after initial immunization. Anti-LM1 antibodies were predominantly of IgG2 subclass. One guinea pig with the highest levels of IgG antibodies exhibited mild signs of neuropathy. There was no evidence of demyelination or inflammation in the sciatic nerves of LM1-immunized guinea pigs. Anti-LM1 antibodies bound to rat sciatic nerve myelin and to isolated rat Schwann cells. In summary, our findings suggest that relatively high levels of anti-LM1 IgG antibodies can be induced in guinea pigs and that LM1 is localized in peripheral nerve myelin and in Schwann cells. Further studies are needed to determine the pathogenic potential of anti-neolactoganglioside antibodies in neuropathy.

Elevated anti-sulfatide antibodies in Guillain-Barré syndrome in T cell depleted at end-stage AIDS.

A 38-year-old man developed the Guillain-Barré syndrome (GBS) associated with untreated end-stage AIDS and CD4+ lymphocyte count of 3 cells/mm(3). The patient had serum high titer anti-sulfatide antibodies and responded well to infusion of immunoglobulin. The data suggest that elevated levels of anti-sulfatide antibodies may play a role in the pathogenesis of GBS in this patient, although a direct neurotropic effect of HIV virus cannot be excluded.

Lewis rats immunized with GM1 ganglioside do not develop peripheral neuropathy.

Elevated levels of anti-GM1 antibodies are associated with motor nerve syndromes. Although there is a lot of circumstantial evidence that anti-GM1 antibodies may be causing the disease, their precise role remains unclear. In order to study the role of anti-GM1 antibodies in the pathogenesis of peripheral neuropathy, eight Lewis rats were injected with GM1 ganglioside mixed with keyhole limpet hemocyanin (KLH) and emulsified with Freund's adjuvant and three rats were immunized with GM1 in liposomes. Although IgM class anti-GM1 antibodies were detected in all animals immunized with GM1, none of the animals exhibited overt signs of neuropathy during 6 months after initial immunization. IgG antibody to GM1 was not produced in any of the animals. There was no pathological evidence of nerve damage. These studies suggest that elevated levels of IgM anti-GM1 antibodies by themselves do not cause nerve damage in rats.

Antibodies to sulfatide in cerebrospinal fluid of patients with multiple sclerosis.

The identity of target antigen(s) in multiple sclerosis (MS) remains elusive despite much effort to identify it. We analyzed cerebrospinal fluid (CSF) from patients with MS, other neurological diseases (OND), other diseases (OD) and healthy controls for antibodies against purified sulfatide, a major glycosphingolipid of human myelin, by an enzyme-linked immunosorbent assay (ELISA) and a thin-layer chromatogram (TLC)-immunostaining technique. Elevated anti-sulfatide antibodies were significantly higher in MS patients as compared with the OND group (p<0.05) and all controls combined (P<0.025). Binding of high titer antibodies to sulfatide was confirmed with TLC-immunostaining. Anti-sulfatide antibodies were detected in all subtypes of MS although the frequency was higher in patients with secondary progressive MS (SPMS) than in patients with primary progressive (PPMS) and relapsing-remitting MS (RRMS). The data demonstrate a humoral response to sulfatide in the CSF of patients with MS.

Generation and characterization of antibodies to sulfated glucuronyl glycolipids in Lewis rats.

Antibodies to sulfated glucuronyl glycolipids (SGGLs) have been reported in sera of patients with peripheral neuropathies including patients with IgM gammopathy. However, the role of anti-SGGL antibodies in the pathogenesis of neuropathy remains unclear. In order to study the role of antibodies to SGGLs in the pathogenesis of neuropathy, Lewis female rats were injected with purified SGPG mixed with keyhole limpet hemocyanin (KLH) and emulsified with equal amount of complete Freund's adjuvant. High titer anti-SGPG antibodies were detected by ELISA in sera of all rats inoculated with SGPG. All anti-SGPG antibodies cross-reacted with human myelin-associated glycoprotein (MAG). None of the sensitized rats exhibited clinical signs of neuropathy. Histological examination showed that there was no demyelination or axonal damage in peripheral nerves. Our data demonstrate that SGPG is a highly immunogenic glycolipid but high titer antibodies against it do not produce an experimental autoimmune neuropathy in Lewis rats.