Factors defining target specificity in antibody-mediated neuropathy: Density-dependent binding of anti-GD1a polyclonal IgG from a neurological patient

IgM and IgG antibodies reacting with components of human brain gangliosides were detected in a patient bearing severe sensory ataxy. Using different chemical and immunological methods, the antigen was identified as the GD_1a ganglioside. The antibodies showed antigen “density-dependent” binding, a property only observed in tumor-specific monoclonal antibodies. The relevance of this result in regard with target specificity of neuropathy-associated antibodies directed to ubiquitous glycolipids is discussed. J. Neurosci. Res. 47: 636–641, 1997. © 1997 Wiley-Liss, Inc.