The
gangliosides GM1 and GD1b have recently been reported to be potential target
antigens in human
motor neuron disease (MND) or motor neuropathy. The mechanism for selective motoneuron and motor nerve impairment by the
antibodies directed against these
gangliosides, however, is not fully understood. We recently investigated the
ganglioside composition of isolated bovine spinal motoneurons and found that the
ganglioside pattern of the isolated motoneurons was extremely complex. GM1, GD1a, GD1b, and GT1b, which are major
ganglioside components of CNS tissues, were only minor species in motoneurons. Among the various
ganglioside species in motoneurons, several were immunoreactive to sera from patients with MND and motor neuropathy. One of these
gangliosides was purified from bovine spinal cord and characterized as
N-glycolylneuraminic acid-containing GM1 [GM1(NeuGc)] by compositional analysis, fast atom bombardment mass spectra, and the use of specific
antibodies. Among seven sera with anti-GM1 antibody activities, five sera reacted with GM1(NeuGc) and two did not. Two other
gangliosides, which were recognized by another patient's serum, appeared to be specific for motoneurons. We conclude that motoneurons contained, in addition to the known
ganglioside antigens GM1 and GD1b, other specific
ganglioside antigens that could be recognized by sera from patients with MND and motor neuropathy.