Human monoclonal immunoglobulin M antibodies to ganglioside GM₁ show diverse cross-reactivities with lipopolysaccharides of <i>Campylobacter jejuni</i> strains associated with Guillain-Barré syndrome.

We examined the reactivity of a panel of anti-GM1 immunoglobulin M monoclonal antibodies (MAbs) cloned from multifocal motor neuropathy patients with lipopolysaccharides (LPSs) of Campylobacter jejuni strains, including serotype O:41 strains associated with Guillain-Barré syndrome. The MAbs reacted with ganglioside GM1 to different degrees, and these differences in fine specificities for GM1 were reflected in the different degrees of reactivity with each of the C. jejuni LPSs tested. Antibodies could also be discriminated by the varying patterns of inhibition by cholera toxin (a GM1 ligand) in LPS binding studies. These results indicate that there is a substantial heterogeneity among C. jejuni O:41 strains in their expression of GM1-like epitopes and among the fine specificities of different neuropathy-associated anti-GM1 antibodies