Antibodies reacting with neighboring gangliosides

MOYANO AL; FUNES SC; NORES AL

Buenos Aires

Simposio; Primer Simposio Argentino de Glicobiología "GlycoAr2014"; 2014

The concept of ?density dependent? binding of antibodies wasproposed in the middle 80´s to explain the behavior of amelanoma-specific monoclonal antibody that recognized GM3,a ubiquitous ganglioside. More recently, antibodies recognizingtwo different gangliosides have been described in Guillain-Barré syndrome (GBS) patients. Although the nature of therecognized antigen is not identified, it has been proposed thatthe antibodies would bind a complex formed by differentgangliosides. Immunization of rabbits with bovine braingangliosides induced an experimental neuropathy, with clinicalsigns resembling GBS. All the immunized animals developedIgG-immunoreactivity to GM1 ganglioside. In a few (4 out of27) animals, an additional anti-ganglioside antibody populationshowing an unusual binding behavior was detected. Enzymelinkedimmunosorbent assay and TLC-immunostaininganalyses showed that binding of these unusual antibodiesrequired the presence of two co-localized gangliosides.Maximal interaction was observed to a mixture of GM1 andGD1b, but the antibodies also showed ?density-dependent?binding to GD1b, indicating that two molecules of GD1bsufficiently close together were also recognized. Theantibodies were purified by affinity chromatography, anddisplayed the ability to target antigens in biological membranes(rat synaptosomes).