Sulfated glucuronyl glycolipids reacting with anti-myelin-associated glycoprotein monoclonal antibodies including IgM paraproteins in neuropathy: species distribution and partial characterization of epitopes.

It was recently established that anti-myelin associated glycoprotein (MAG) IgM paraproteins associated with neuropathy and a substantial number of experimentally produced rat and mouse monoclonal antibodies that react with MAG (e.g. HNK-1) also bind to some sulfated glucuronic acid-containing sphingoglycolipids of human peripheral nerve.

Structure of sulfated glucuronyl glycolipids in the nervous system reacting with HNK-1 antibody and some IgM paraproteins in neuropathy.

Novel sulfated glucuronic acid-containing glycolipids have been identified in the nervous system. These glycolipids are highly antigenic and share antigenic determinants with several nervous system glycoproteins, such as neural cell adhesion molecules, myelin-associated glycoprotein, and ependymins. The structure of the major antigenic glycolipid from human peripheral nerve was determined by chemical and enzymatic degradation, incorporation studies, sugar analysis after permethylation, pertrimethylsilylation, and gas liquid chromatography-mass spectrometry techniques as well as fast atom bombardment-mass spectrometry of the native antigen.

Mouse monoclonal and rabbit polyclonal antibodies prepared to human myelin-associated glycoprotein also react with glycosphingolipids of peripheral nerve.

A panel of mouse monoclonal antibodies and rabbit polyclonal antisera that were raised to myelin-associated glycoprotein (MAG) were screened for reactivity with acidic glycolipids from brain and peripheral nerve by enzyme-linked immunosorbent assay (ELISA) and/or a thin-layer chromatogram overlay technique. Seven out of 7 mouse monoclonal antibodies that recognize carbohydrate epitopes in human MAG also reacted with acidic glycolipids from human and cat peripheral nerve, while monoclonal antibodies that react with polypeptide epitopes on MAG did not react with these glycolipids. Rabbit anti-human MAG antisera also strongly reacted with the glycolipids from peripheral nerve, while rabbit antisera raised to rat MAG did not.

Specificity of human IgM monoclonal antibodies from patients with peripheral neuropathy.

Some patients with peripheral neuropathy and gammopathy have IgM monoclonal antibodies that react with the myelin-associated glycoprotein (MAG), some 20-26 kDa glycoproteins present only in the peripheral nervous system (PNS), and some acidic glycolipids that are also PNS-specific. This communication describes an investigation of 18 patients with IgM paraproteinemia and neuropathy to test for the presence of antibodies that react with each of these components. Eleven patients had IgM that reacted with MAG, and in all cases the IgM also reacted with the lower Mr glycoproteins and the acidic glycolipids that are specific for the PNS.

Monoclonal IgM in a patient with paraproteinemic polyneuropathy binds to gangliosides containing disialosyl groups.

Monoclonal IgM kappa from a patient with polyneuropathy associated with paraproteinemia was found to bind to several polysialogangliosides. Binding of IgM to gangliosides was shown by enzyme-linked immunosorbent assay (ELISA) and by overlaying thin-layer chromatograms of human brain and peripheral nerve gangliosides with the patient's serum followed by radioiodinated goat antihuman IgM. The latter technique showed that the IgM paraprotein reacted with a number of gangliosides.

Polyneuropathy with monoclonal gammopathy: glycolipids are frequently antigens for IgM paraproteins.

Immunoglobulins from patients with paraproteinemic polyneuropathy were screened for reactivity with nerve and brain glycolipids by ELISA and/or a thin-layer-chromatogram-overlay technique. The myelin-associated glycoprotein (MAG) has been shown to be an antigen in many neuropathy patients with IgM gammopathy, but this study focused on seven neuropathy patients in which the IgM paraproteins had been shown not to react with this glycoprotein. Five of these seven had IgM that reacted with components in the acidic glycolipid fraction of human sciatic nerve, and three of these IgMs also reacted with components in the acidic glycolipid fraction of human brain.

Structure of a glycolipid reacting with monoclonal IgM in neuropathy and with HNK-1.

An acidic glycolipid antigen that reacts with monoclonal IgM in patients with demyelinating neuropathy and with the mouse monoclonal antibody, HNK-1, was purified from human peripheral nerves. This lipid sharing antigenic determinants with the myelin-associated glycoprotein was shown to be an unusual glucuronic acid-containing sulfated glycosphingolipid with five sugars, but without sialic acid. Mild acid methanolysis converted the GlcUA to its methyl ester, removed the acidic sulfate group and abolished the antigenicity.

The monoclonal antibody HNK-1 reacts with a human peripheral nerve ganglioside.

The monoclonal HNK-1 antibody, a marker for human natural killer cells, strongly reacted with human peripheral nerve gangliosides in the enzyme-linked immunosorbent assay. Autoradiography after the binding of HNK-1 to thin-layer chromatograms of peripheral nerve gangliosides followed by radioiodinated goat anti-mouse IgM revealed that HNK-1 was reacting with a minor ganglioside that chromatographed between GM1 and GD1a. The antigen was insensitive to digestion with neuraminidase and pronase.

IgM in a human neuropathy related to paraproteinemia binds to a carbohydrate determinant in the myelin-associated glycoprotein and to a ganglioside.

The IgM in three patients with paraproteinemia and peripheral neuropathy was shown to bind to human myelin-associated glycoprotein (MAG) that had been purified to homogeneity by gel filtration on Sepharose CL-6B. The antigenic determinant reacting with the IgM from all three patients was in the carbohydrate part of the MAG molecule. In addition, the IgM from the same three patients bound to a single ganglioside of human sciatic nerve.

Cellular hypersensitivity to gangliosides and myelin basic protein in multiple sclerosis.

Peripheral blood lymphocytes from patients with multiple sclerosis (MS), other neurological diseases and healthy controls were investigated for the presence of cell-mediated hypersensitivity to brain gangliosides and myelin basic protein using an active E-rosette assay. Sensitivity to myelin basic protein and gangliosides was found in MS patients in acute relapse and with progressive disease, whereas no sensitivity was found in MS patients in remission. Patients with other neurological diseases showed no response to gangliosides, but sensitization to myelin basic protein was found in a patient with leucoencephalopathy and in 4 of 6 stroke patients.

Cyclosporin A inhibits ganglioside-stimulated lymphocyte rosette formation in multiple sclerosis.

Brain gangliosides have been found to stimulate active lymphocyte rosette formation in patients with multiple sclerosis during an active phase of the illness. On antigenic stimulation, a soluble factor is released which enhances active rosette formation. These reactions do not occur in multiple sclerosis patients during remission, in other neurological diseases or in controls that we have tested.